JP2018067888A - Antenna and radar - Google Patents

Abstract

An antenna capable of improving the gain of an antenna and thereby improving the detection performance of a radar equipped with the antenna. A substrate, one or more cavities provided inside the substrate and functioning as a waveguide, and the substrate penetrating from the one or more cavities to the substrate surface as a slot antenna. One or more slot elements for functioning, and a first hollow of the one or more hollows, in the vicinity of the slot surface, which is a surface on which the hollow is projected on the substrate surface, An antenna in which one or more grooves extending parallel to the longitudinal direction of the first hollow tube are formed. [Selection] Figure 3

Description

  The present invention relates to an antenna and a radar.

  For example, as described in Japanese Patent Laid-Open No. 5-22025 (Patent Document 1), a conventional waveguide slot antenna generally employs a method in which a large number of waveguides are arranged in parallel in order to increase antenna gain. Is.

Japanese Patent Laid-Open No. 5-22025

  However, when the number of waveguides is increased, there is a problem that the structure becomes complicated and the whole antenna is increased in size.

An antenna according to the present invention functions as a slot antenna, which is provided inside a substrate, one or more hollows to function as a waveguide, and penetrates from one or more hollows to the substrate surface. One or more slot elements for extending the first hollow of the one or more cavities in the vicinity of the slot surface defined below and extending parallel to the longitudinal direction of the first hollow tube One or more grooves are formed.
Slot surface: The surface where a hollow is projected on the substrate surface

  The radar according to the present invention is equipped with the antenna described above.

  According to the present invention, the gain of the antenna can be improved. Thereby, the detection performance of the radar equipped with the antenna can be improved.

It is a figure for demonstrating the definition of the direction in an antenna. It is the figure which represented typically an example of the structure of the radar carrying the antenna concerning 1st Embodiment. It is the figure which represented typically an example of the structure of the antenna concerning 1st Embodiment. It is a figure for demonstrating the size common to the antenna model used for the simulation by inventors. It is the schematic of the cross section of the antenna model of the conditions 2 of 1st simulation. It is the schematic of the cross section of the antenna model of the conditions 3 of 1st simulation. It is the schematic of the cross section of the antenna model of the conditions 4 of 1st simulation. It is the schematic of the cross section of the antenna model of the conditions 5 of 1st simulation. It is a list showing the result of the 1st simulation. It is the schematic of the cross section of the antenna model of the conditions 6 and 7 of 2nd simulation. It is the schematic of the cross section of the antenna model of the conditions 8 of 2nd simulation. It is the schematic of the cross section of the antenna model of the conditions 9 and 10 of 2nd simulation. It is the list showing the result in condition 6 (A) and condition 7 (B) of the 2nd simulation. It is the list showing the result in condition 8 of the 2nd simulation. It is the list showing the result in condition 9 (A) and condition 10 (B) of the 2nd simulation. It is the schematic of the cross section of the antenna model of the conditions 11 of 3rd simulation. It is the schematic of the cross section of the antenna model of the conditions 12 of 3rd simulation. It is a list showing the result of the 3rd simulation. It is the schematic of the cross section of the antenna model of the conditions 15 of 4th simulation. It is the schematic of the cross section of the antenna model of the conditions 16 of 4th simulation. It is the schematic of the cross section of the antenna model of the conditions 17 of 4th simulation. It is the schematic of the cross section of the antenna model of the conditions 18 of 4th simulation. It is the schematic of the cross section of the antenna model of the conditions 19 of 4th simulation. It is the schematic of the cross section of the antenna model of the conditions 20 of 4th simulation. It is the schematic of the cross section of the antenna model of the conditions 21 of 4th simulation. It is the schematic of the cross section of the antenna model of the conditions 22 of 4th simulation. It is the schematic of the cross section of the antenna model of the conditions 23 of 4th simulation. It is the schematic of the cross section of the antenna model of the conditions 24 of 4th simulation. It is the list showing the result for every slot antenna of the 4th simulation. It is a list showing the result of the 4th simulation. It is the schematic of the cross section of the antenna model of the conditions 25 of 5th simulation. It is the schematic of the cross section of the antenna model of the conditions 26 of 5th simulation. It is a list showing the result of the 5th simulation. It is the figure which represented typically an example of the structure of the antenna concerning 2nd Embodiment. It is the schematic of the cross section of the antenna model of the conditions 28 of 6th simulation. It is the schematic of the cross section of the antenna model of the conditions 29 of 6th simulation. It is the schematic of the cross section of the antenna model of the conditions 30 of 6th simulation. It is a list showing the result of the 6th simulation. It is a figure for demonstrating an example of the manufacturing method of an antenna. It is a figure for demonstrating the other example of the groove | channel provided between adjacent slot antennas. It is a figure for demonstrating an example of the attachment method to the board | substrate of a board member.

[Description of Embodiment]
This embodiment includes at least the following.
That is, according to one embodiment, an antenna is provided on a substrate, one or more cavities for functioning as a waveguide, and one or more cavities penetrating from the one or more cavities to the substrate surface. One or more slot elements for functioning as a slot antenna, the first hollow tube length in the vicinity of the first hollow of the one or more hollow, the slot surface defined below One or more grooves extending parallel to the direction are formed.
Slot surface: plane in which a hollow is projected on the substrate surface The inventors have verified through simulation that the antenna gain can be improved by the above configuration. As a result, the gain of the antenna can be improved without increasing the number of slot antennas, so that the detection accuracy can be improved while suppressing the complexity and enlargement of the configuration of the radar equipped with the antenna. .

Preferably, the one or more grooves are formed on the substrate surface at a position sandwiching the surface of the first hollow slot, and each include two grooves extending in parallel to the longitudinal direction of the first hollow tube.
The inventors have verified through simulation that the antenna gain can be further improved by the above configuration. As a result, the gain of the antenna can be improved without increasing the number of slot antennas, so that the detection accuracy can be improved while suppressing the complexity and enlargement of the configuration of the radar equipped with the antenna. .

Preferably, the one or more hollows further include a second hollow provided so that a longitudinal direction of the tube is parallel to the first hollow, and the first hollow of the one or more grooves is included. The grooves formed in the substrate surface between the slot surface and the second hollow slot surface are equally spaced from the first hollow and the second hollow.
According to said structure, the influence of the said groove | channel with respect to each of the 1st slot antenna and 2nd slot antenna which are adjacent on both sides of a groove | channel can be made equal.

Preferably, the first hollow and the second hollow are connected to a common feeder line.
The inventors verified by simulation that the gain of the antenna can be improved even with the above configuration. As a result, the gain of the antenna can be improved without increasing the number of slot antennas, so that the detection accuracy can be improved while suppressing the complexity and enlargement of the configuration of the radar equipped with the antenna. .

Preferably, the one or more hollows further include a second hollow provided so that a longitudinal direction of the tube is parallel to the first hollow, and the one or more grooves are formed on the first surface of the substrate. The first hollow slot surface and the second hollow slot are formed so as to sandwich the hollow and second hollow slot surfaces and each include two grooves extending parallel to the longitudinal direction of the first hollow tube. No groove is formed between the surface.
The inventors have verified by simulation that the antenna gain can be further improved by the above-described configuration. As a result, the gain of the antenna can be improved without increasing the number of slot antennas, so that the detection accuracy can be improved while suppressing the complexity and enlargement of the configuration of the radar equipped with the antenna. .

Preferably, the one or more slot elements include a plurality of slot elements arranged along the longitudinal direction of the hollow tube, and the one or more grooves are adjacent to each other in the longitudinal direction of the tube through the partition wall, It includes two grooves extending in the hand direction, and the partition wall portion is located at a position where at least one of the first hollow slot elements is provided in a direction orthogonal to the traveling direction of the electromagnetic wave as viewed from the partition wall portion. Is not formed, and is formed at a position where none of the first plurality of hollow slot elements is provided in a direction orthogonal to the traveling direction of the electromagnetic wave as viewed from the partition wall.
According to said structure, since a groove | channel is located between adjacent slot elements, the influence on the other of each signal of these two slot elements is suppressed effectively.

Preferably, the wall thickness which is the distance from the wall facing the first hollow of the groove closest to the first hollow of the one or more grooves to the wall facing the first hollow of the closest groove is 0. It is 27λ (λ: wavelength of the frequency used by the antenna) or less.
The inventors verified by simulation that the gain of the antenna can be improved by the above configuration. As a result, the gain of the antenna can be improved without increasing the number of slot antennas, so that the detection accuracy can be improved while suppressing the complexity and enlargement of the configuration of the radar equipped with the antenna. .

Preferably, the depth of the one or more grooves is 0.51λ or less.
The inventors verified by simulation that the gain of the antenna can be improved by the above configuration. As a result, the gain of the antenna can be improved without increasing the number of slot antennas, so that the detection accuracy can be improved while suppressing the complexity and enlargement of the configuration of the radar equipped with the antenna. .

Preferably, the one or more grooves are a first groove formed in the vicinity of the first hollow slot surface on the substrate surface, and a first groove adjacent to the first groove far from the first hollow. Includes two grooves.
The inventors verified by simulation that the gain of the antenna can be improved by the above configuration. As a result, the gain of the antenna can be improved without increasing the number of slot antennas, so that the detection accuracy can be improved while suppressing the complexity and enlargement of the configuration of the radar equipped with the antenna. .

Preferably, the substrate has a stacked structure in which a plurality of plates are stacked, and the plurality of plates includes a first plate having a first surface and a second plate disposed on the back side of the first surface. The first plate has a first through hole that forms one or more grooves, and a second through hole that forms a slot element, and the second plate It has a region that closes the through hole.
According to said structure, formation of an antenna can be made easy. In particular, when the wavelength of the frequency used by the antenna is a small wavelength such as a millimeter wave, the antenna can be formed more easily.

Preferably, the antenna is provided with a conductor member in front of the first surface of the substrate and in front of a region where one or more grooves are formed.
The inventors verified by simulation that the gain of the antenna can be improved by the above configuration. As a result, the gain of the antenna can be improved without increasing the number of slot antennas, so that the detection accuracy can be improved while suppressing the complexity and enlargement of the configuration of the radar equipped with the antenna. .

According to another embodiment, the radar is equipped with the antenna described above.
As a result, it is possible to improve the detection accuracy while preventing the configuration from becoming complicated and large.

[Details of the embodiment]
Hereinafter, preferred embodiments will be described with reference to the drawings. In the following description, the same parts and components are denoted by the same reference numerals. Their names and functions are also the same. Therefore, these descriptions will not be repeated.

[First Embodiment]
<Definition of antenna>
The radar according to the present embodiment is equipped with an antenna including a slot antenna that is an antenna for wireless communication. First, the antenna is defined. The slot antenna includes a single waveguide having a circular or square cross-section hollow used for radio wave transmission. One waveguide is provided with one or a plurality of slot elements which are through holes from the hollow of the waveguide toward the outside. The waveguide here does not mean a tubular member composed of one hollow and the outer circumference of the hollow having a circular or square cross section, but a hollow of a circular or rectangular cross section serving as an electromagnetic wave transmission path. Refers to itself.

  One antenna includes one or more slot antennas. When the antenna includes a plurality of slot antennas, the plurality of slot antennas are arranged so that the longitudinal directions of the tubes are parallel to each other. The direction in which the waveguides are arranged, that is, the direction orthogonal to the longitudinal direction of the tube is also called the width direction of the antenna.

  The antenna system is composed of one or more slot antennas that share a feed line connected to each waveguide. When used as a receiving antenna, when the same antenna system is composed of a plurality of slot antennas, a combined radio wave from the plurality of slot antennas is output as a received radio wave to the feeder line. The angle of the object to be detected with respect to the antenna is calculated based on the phase difference of the radio waves between the plurality of antenna systems received simultaneously. Also, when used as a transmission antenna, when the same antenna system is composed of a plurality of slot antennas, the transmission wave input from the feeder is distributed to the plurality of slot antennas and the radio waves radiated from the respective slot antennas. Are combined into a radiated radio wave.

  Of the surface of the waveguide, the surface on which the slot element is provided is defined as the surface (slot surface) of the slot antenna. The slot surfaces of all the one or more slot antennas included in one antenna are included in one plane. Note that this includes not only the case where all the slot surfaces completely coincide with one plane, but also the case where, for example, the slot surfaces are somewhat uneven with respect to the one plane. A member having this plane as a surface is referred to as a substrate. In other words, the slot surface is a surface obtained by projecting the hollow of the waveguide onto the substrate surface. In the antenna, one or more cavities for functioning as a waveguide are provided inside the substrate, and the slot element is provided from the hollow to the surface of the substrate provided to function the substrate as a slot antenna. It is a through hole.

  The substrate surface is the front of the antenna. The front from the front of the antenna (a position having a positive distance from the front) is the front direction of the antenna, and the rear from the front of the antenna is the back direction of the antenna. The direction from the front of the antenna to the rear indicates the direction from the front of the antenna toward the inside of the antenna. The front from the front of the antenna is the reverse of the rear, and refers to the direction far from the antenna with the front of the antenna as a base point.

  The slot antenna is designed based on the wavelength of the radar wave to be transmitted / received by the antenna. The frequency of the radar wave to be transmitted / received by the antenna is also called an antenna use frequency. When the operating frequency is 76.5 GHz, which is a general operating frequency of a radar using a millimeter wave band called a millimeter wave radar, the design wavelength λ of the slot antenna is 3.92 mm.

<Definition of direction>
The antenna is generally installed such that the longitudinal direction of the tubes of the plurality of arrayed slot antennas is vertical, such as an antenna in a vehicle-mounted radar. The horizontal plane of the antenna refers to the horizontal plane when the antenna is installed in this way. The direction of the antenna is defined as shown in FIG. Referring to FIG. 1, the direction of arrow A is defined as an angle in the + direction in the horizontal direction. That is, in the horizontal plane, the angle in the front direction of the antenna is 0 °, and 90 ° counterclockwise from the front of the antenna is the angle in the + direction. The arrow B direction is defined as an angle in the minus direction in the horizontal direction. That is, in the horizontal plane, an angle of 90 ° clockwise from the front of the antenna is defined as an angle in the − direction. The arrow C direction is the angle in the + direction in the vertical direction. That is, in the vertical plane, the angle in the front direction of the antenna is 0 °, and the angle from the front of the antenna to 90 ° downward is the angle in the + direction. The arrow D direction is defined as an angle in the − direction in the vertical direction. That is, in the vertical plane, an angle of 90 ° upward from the front of the antenna is defined as an angle in the − direction. When the antenna is thus installed, the radar detection angle generally refers to an angle that can be detected on the horizontal plane of the antenna. The detection angle may be expressed in both positive and negative directions in the horizontal plane with respect to the front surface of the antenna.

<Antenna configuration>
In order to obtain a high gain with a slot antenna, it is generally considered that the number of slot antennas included in the antenna is increased. The antenna gain refers to the intensity of energy at the radiation angle at which radiation is maximized, and specifically refers to the ratio of received power when the target antenna and the reference antenna receive signals in the same electric field. Raising the gain improves the radar detection accuracy. However, as the number of slot antennas increases, the antenna structure becomes complicated. In addition, the antenna size becomes large. Therefore, the inventors designed an antenna that improves the gain regardless of the increase in the number of slot antennas.

  FIG. 2 is a diagram schematically illustrating an example of the configuration of the radar 300 on which the antenna 100 according to the first embodiment is mounted. FIG. 2 is a view of the antenna 100 as viewed from the front. In FIG. 2, a metal plate 50 described later is omitted. FIG. 3 is a diagram schematically illustrating an example of the configuration of the antenna 100. FIG. 3 is a cross-sectional view taken along the line AA in FIG.

  2 and 3, an antenna 100 according to the first embodiment includes a plurality of slot antennas 20A to 20E. The slot antennas 20A to 20E are collectively referred to as a slot antenna 20. In FIG. 2, the width direction of the antenna 100 is the x direction, and the longitudinal direction of the waveguide is the y direction. As defined in FIG. 2, one direction in the x direction is + x direction, the opposite direction is −x direction, one direction in y direction is + y direction, and the opposite direction is −y direction. To do. Further, in FIG. 3, the direction orthogonal to the surface 10a of the substrate 10 is defined as the z direction. As defined in FIG. 3, the direction away from the substrate surface 10a, that is, the front direction of the antenna 100 is the + z direction, and the direction toward the inside of the substrate 10, that is, the rear direction of the antenna is the −z direction.

  Specifically, referring to FIG. 2 and FIG. 3, the slot antennas 20A to 20E include one waveguide 11A to 11E and one longitudinal direction (second direction) of each of the waveguides 11A to 11E. And a plurality of slot elements 12 arranged along the line. The waveguides 11A to 11E are collectively referred to as the waveguide 11. The waveguides 11A to 11E all correspond to the first hollow. That is, the waveguide 11 is the first hollow. Providing each slot antenna 20 with a plurality of slot elements 12 can improve the detection accuracy of the radar 300 on which the antenna 100 is mounted.

  The substrate 10 is a plate member having a thickness formed of a conductor such as metal. The waveguides 11 of the plurality of slot antennas 20 are all arranged in the substrate 10 so that the longitudinal direction of the tubes is parallel so that the slot surface 11a coincides with or substantially coincides with the surface 10a of the substrate 10. . That is, the hollows of the plurality of waveguides 11 are drilled in the substrate 10 in parallel. The term “substantially coincidence” here refers not only to the case where all the slot surfaces 11a of the plurality of slot antennas 20 are completely coincident with the surface 10a of the substrate 10, but also, for example, the slot surface 11a relative to the substrate surface 10a This includes the case where is slightly uneven. FIG. 3 shows an example in which the back surface side of the substrate 10 is also a flat surface. However, the substrate 10 may be a flat surface including at least the front surface 10a including the slot surface 11a, and the waveguide 11 on the back surface side exists. Except for the portion to be formed, the conductor may not exist and may be a depression.

  From the waveguide 11 to the substrate surface 10a, slot elements for causing the substrate 10 to function as a slot antenna are perforated along the traveling direction (longitudinal direction) of the electromagnetic wave in each waveguide 11. As described above, by forming the plurality of slot antennas 20 using the substrate 10, the antenna 100 can be easily manufactured. In addition, the antenna 100 can be easily handled.

  Since FIG. 2 is a view of the antenna 100 as seen from the front, the waveguide 11 is indicated by a dotted line from the substrate surface 10a. In other words, the range indicated by the dotted line as the waveguide 11 in FIG. 2 is the range where the hollow of the waveguide 11 is projected onto the substrate 10, that is, the slot surface 11a.

Referring to FIG. 2, as an example, a plurality of slot elements 12 included in one slot antenna 20 are arranged in two rows along two straight lines C _SL and C _SR in the longitudinal direction of one waveguide 11. Arranged. The plurality of slot elements 12 need only be generally arranged along two straight lines C _SL and C _SR , and their centers are not necessarily directly above one of the two straight lines C _SL and C _SR. May be. The two straight lines C _SL and C _SR are located at equal distances across the center line Cw of the waveguide 11 in the longitudinal direction of the tube. The center line Cw is also the center line in the width direction of the slot antenna 20. The plurality of slot elements 12 are arranged at equal intervals in the longitudinal direction of the pipe along the straight lines C _SL and C _SR . Widthwise position of a plurality of slot elements 12 and a plurality of slot elements 12 along the line C _SR along the line C _SL do not match, are arranged alternately. The plurality of slot elements may all have the same shape, or may have a slight size difference. In the following description, all the shapes of a plurality of slot elements 12 and the same as, linear C _SL of the center are two, C _SR located either directly above two straight lines C _SL, along the C _SR Shall be arranged.

  The plurality of slot antennas 20A to 20E are separated into slot antennas 20A to 20D and a slot antenna 20E. The slot antennas 20A to 20D and the slot antenna 20E are arranged in parallel in the y direction. The arrangement of the slot antennas 20A to 20D and the slot antenna 20E is not limited to the example in FIG. As another example, the slot antennas 20A to 20D and the slot antenna 20E may be separated and arranged in parallel in the x direction. In the slot antenna 20A, the slot antenna 20B is arranged on one side of both sides in the width direction, and no other slot antenna is arranged on the other side. Further, in the slot antenna 20D, the slot antenna 20C is arranged on one side of both sides in the width direction, and no other slot antenna is arranged on the other side. None of the slot antennas are arranged on both sides in the width direction of the slot antenna 20E. The configuration of the plurality of slot antennas 20A to 20E may be a configuration other than that described in FIG. 2 and above. That is, FIG. 2 shows an example of a configuration divided into four slot antennas and one slot antenna. For example, as a receiving antenna system, seven slot antennas and transmission antennas are used. The system may be configured with two slot antennas, the reception antenna system with one slot antenna, or the transmission antenna system with one slot antenna.

  In the antenna 100 according to the first embodiment, each of the slot antennas 20A to 20D constitutes a receiving antenna system. That is, the antenna 100 according to the first embodiment includes the first receiving antenna system configured by the slot antenna 20A, the second receiving antenna system configured by the slot antenna 20B, and the slot antenna 20C. It includes a third receiving antenna system configured and a fourth receiving antenna system configured by the slot antenna 20D. Each receiving antenna system is connected to the receiver 170 by an independent feeder line. That is, each of the slot antennas 20A to 20D is connected to the receiver 170 by an independent feeder line. In the antenna 100 according to the first embodiment, the slot antenna 20E constitutes a transmission antenna system. The slot antenna 20E is connected to the transmitter 150.

  In the slot antennas 20A to 20D, the interval L1 between the adjacent slot antennas 20 is, for example, about 2.0λ. Preferably, the interval L1 is 1.5λ or less. More preferably, the interval L1 is 1.2λ or less, for example, 1.0λ or less. The interval L1 between adjacent slot antennas 20 refers to the distance between the center line Cw extending in the tube longitudinal direction of the slot antenna 20 and the center line Cw of the slot antenna 20 adjacent to the slot antenna 20 with reference to FIG. It is. This is because the detection angle in the radar 300 can be made wider by making the interval L1 between adjacent slot antennas 20 as narrow as possible. Further, the antenna 100 can be downsized.

  Further, the gap L2 between adjacent slot antennas 20 is set to 0.05 (1/20) λ or more, for example. The gap L <b> 2 between the adjacent slot antennas 20 is a gap between the waveguides 11 of the adjacent slot antennas 20, in other words, an interval between the slot surfaces of the adjacent slot antennas 20. Specifically, referring to FIG. 2, the gap between adjacent slot antennas 20 is a distance L <b> 2 between end portions of waveguide 11 on the side close to adjacent slot antennas 20. By narrowing the gap L2 between the slot antennas 20 while the interval L1 between the adjacent slot antennas 20 is narrowed as described above, a groove 40 and a metal plate 50 which will be described later are easily arranged. In the case of λ = 3.92 mm, if L2 becomes smaller than 0.05λ (= 0.20 mm), the manufacture is difficult.

  The transmitter 150 generates a transmission wave having a wavelength λ of the frequency used by the antenna. When the radar 300 is a millimeter wave radar, the transmitter 150 generates a transmission wave in the millimeter wave band of 20 GHz or more. A transmission wave generated in the transmitter 150 reaches the plurality of slot elements 12 provided in the slot antenna 20E through the waveguide 11E. Then, the transmission wave is emitted from each slot element 12 in a predetermined direction.

  The radio wave having the wavelength of the use frequency of the antenna reaching the antenna 100 is received by the plurality of slot elements 12 provided in each of the slot antennas 20A to 20D. The received wave is sent from the slot element 12 to the receiver 150 through each waveguide 11. When the radar 300 is a millimeter wave radar, an electromagnetic wave in the millimeter wave band of 20 GHz or higher is sent to the receiver 150. The receiver 150 performs a prescribed process on the radio waves received by the slot antennas 20A to 20D. When a detection target exists in the detection range of the radar 300, the radio wave emitted from the slot antenna 20E is reflected by the detection target. The reflected radio waves are received by the slot antennas 20A to 20D.

  Based on the time from when the radio wave is emitted to when it is received, the distance of the detection target from the antenna 100 is calculated. The angle of the detection target with respect to the antenna 100 is calculated based on the phase difference of the received radio waves in the first to fourth receiving antenna systems configured by the slot antennas 20A to 20D.

  One or more recesses are formed in the vicinity of the slot surface 11a of the substrate surface 10a in the x direction. For example, one or more recesses are formed in the vicinity of the −x side with respect to the slot surface 11a of the slot antenna 20A. One or more recesses are also formed near the + x side with respect to the slot surface 11a of the slot antenna 20A. The vicinity on the + x side with respect to the slot surface 11a of the slot antenna 20A is also the vicinity on the −x side with respect to the slot surface 11a of the slot antenna 20B. The one or more recesses formed at this position can be said to be a recess formed on the substrate surface 10a between the slot antenna 20A and the slot antenna 20B. The vicinity here refers to a range of distance in which the gain of the slot antenna is improved by forming the recess. When the neighborhood is represented by the wall thickness m between the slot antenna and the nearest concave portion, the wall thickness m that can be said to be the neighborhood is a range of distance up to about 1.5λ, for example. As described above, when the interval L1 between the slot antennas 20 is about 2.0λ, the wall thickness m that can be said to be in the vicinity is, for example, in the range of 1.0λ or less.

  The recesses are formed in the vicinity of the slot antenna 20 and at least in the vicinity of all the slot elements 12 provided in the slot antenna 20 in the x direction. As an example, the concave portion is a groove provided in parallel with the slot antenna 20 and extending in the longitudinal direction of the tube, that is, in the y direction. By forming the recesses into grooves, the recesses can be formed in the vicinity of all the slot elements 12 of the slot antenna 20 and can be easily formed. Specifically, in the antenna 100, as shown in FIGS. 2 and 3, grooves 40B extending in the y direction are formed on the substrate surface 10a between the slot antennas 20A and 20B, 20B and 20C, and 20C and 20D, respectively. , 40C, 40D are formed. The grooves..., 40B, 40C, 40D,.

  Specifically, referring to FIG. 2, the groove 40 which is a recess extends along a center line Cg parallel to the y direction, that is, the tube longitudinal direction of the waveguide 11. Preferably, the recesses are provided at equal intervals from the two adjacent slot antennas 20. That is, the distance between the center line Cg and the center line Cw of each of the two adjacent slot antennas 20 is a distance l (el). The distance l (el) has a relationship of L = 2 × l (el) with respect to the distance L1 between the center lines Cw. By providing the groove 40 at such a position, the influence of the groove 40 on each of the two adjacent slot antennas 20 with the groove 40 interposed therebetween can be made uniform. Moreover, when an example of the manufacturing method mentioned later is employ | adopted for the manufacturing method of the antenna 100, formation of the antenna 100 can be made easy. The wall thickness m between the slot antenna 20 and the groove 40 closest to the slot antenna 20 is the distance between the groove 40 and the hollow of the waveguide 11 of the slot antenna 20, and the slot antenna 20 in the groove 40. The distance from the wall surface facing toward the wall surface toward the hollow groove 40 of the waveguide 11 of the slot antenna 20.

  The depth (length in the z direction) of the groove 40 is a depth exceeding the depth from the slot surface 11 a to the waveguide 11. Alternatively, the depth of the groove 40 may be shallower than the depth from the slot surface 11 a to the waveguide 11. The width (the length in the x direction) of the groove 40 is smaller than the interval between the slot surfaces 11 a of the adjacent slot antennas 20. Preferably, the width of the groove 40 is 0.05λ to 0.26λ. The wall thickness m between the groove 40 closest to the slot antenna 20 and the slot antenna 20 is preferably 0.27λ or less. The depth of the groove 40 is preferably 0.51λ or less. More preferably, the depth of the groove 40 is around 0.3λ.

  Referring to FIG. 3, a conductor member is preferably provided at a position on the + z side from slot surface 11 a of slot antenna 20 and on the + z side from groove 40. The conductor is a metal, for example. By forming the conductor member as a metal plate, it can be easily formed.

  The length of this member in the width direction of the antenna 100 is shorter than the gap L <b> 2 between the waveguides 11 of the two adjacent slot antennas 20. This member is a plate member (metal plate) such as a metal extending in the y direction, for example. That is, as shown in FIG. 3, the metal plates 50A, 50B, extending in the tube longitudinal direction of the waveguide 11 from the + x side substrate surface 10a of the slot antennas 20A, 20B, 20C, respectively, to the + z side position. 50C is formed. The metal plates 50A,... Are collectively referred to as the metal plate 50.

  Note that both the groove 40 and the member such as the metal plate 50 may be provided in the antenna 100, or only one of them may be provided.

  The inventors who designed the antenna 100 described above have the strength of the slot antenna 20 under various conditions in which the groove 40 and the metal plate 50 as the member are changed using a part of the antenna 100 according to the first embodiment. The design directivity of the antenna 100 was verified.

  FIG. 4 is a diagram for explaining a size common to the antenna models used in the simulation. Each antenna model is designed with a use frequency of 76.5 GHz, which is a general use frequency of millimeter wave radar, and a wavelength of millimeter wave radar as a design wavelength λ (λ = 3.92 mm). Referring to FIG. 4, the slot antenna 20 included in each antenna model has a length in the longitudinal direction (y direction) of 18.86 mm (≈4.81λ) and a width (length in the x direction) of 2.54 mm ( The groove 40 provided in the vicinity (side) has a length in the tube longitudinal direction (y direction) of 20.86 mm (≈5.32λ). The cross-sectional views of the antenna model under the following conditions are cross-sectional views at the BB position in FIG.

<< First simulation >>
The first simulation is a simulation for confirming the presence / absence of a groove on the side of the slot antenna 20 by using an antenna model having only one slot antenna 20 (one system) as a receiving antenna system.

<First simulation condition>
In the first simulation, the following conditions 1 to 5 were applied.
Condition 1) A simulation using an antenna model of only the slot antenna 20 without providing a groove or the like.
Condition 2) A simulation using an antenna model in which one groove 40 is provided in the vicinity of the −x side of the slot antenna 20.
Condition 3) A simulation using an antenna model in which one groove 40 is provided in the vicinity of the slot antenna 20 on the + x side.
Condition 4) A simulation using an antenna model in which two grooves 40 are provided in the vicinity of the −x side of the slot antenna 20.
Condition 5) A simulation using an antenna model in which two grooves 40 are provided in the vicinity of the + x side of the slot antenna 20.

  5 to 8 are schematic views of a cross section of the antenna model used in the simulations of conditions 2 to 5. FIG. Referring to FIG. 5, the antenna model used in the simulation of condition 2 is provided with a single groove 40 that is 0.21 mm (≈0.05λ≈1 / 20λ) apart from the slot antenna 20 in the −x direction. Yes. The groove 40 has a width (length in the x direction) of 0.3 mm (≈0.08λ) and a depth (length in the z direction) of 1 mm (≈0.26λ≈1 / 4λ). With reference to FIG. 6, the antenna model used in the simulation of condition 3 is obtained by inverting the antenna model of condition 2 in the x direction.

  Referring to FIG. 7, the antenna model used in the simulation of condition 4 is provided with a first groove 40 that is 0.21 mm (≈0.05λ≈1 / 20λ) apart from the slot antenna 20 in the −x direction. Further, a second groove 40 is provided at a distance of 0.3 mm (≈0.08λ). The width and depth of the groove 40 are the same as those in the conditions 2 and 3. Referring to FIG. 8, the antenna model used in the simulation of condition 5 is obtained by inverting the antenna model used in the simulation of condition 4 in the x direction.

<First simulation result>
FIG. 9 is a list showing gains obtained from the simulation results of conditions 1 to 5 respectively. When the gain is high, the radio wave emitted from the antenna 100 reaches a long distance. For this reason, the distance that can be detected by the radar 300 on which the antenna 100 is mounted becomes longer. Therefore, it can be said that the detection performance of the radar 300 equipped with the antenna 100 is higher as the gain is higher. In this verification, the gain in the direction in which the horizontal plane is the front of the antenna (in the direction of 0 °) and the maximum gain (peak) in the vertical plane is used as the gain of the antenna to evaluate the gain improvement effect. That is, the value of 0 [°] of the simulation result obtained under each condition is used as the evaluation target. The same applies to the subsequent verification. However, the gain of the antenna is not limited to the directivity of the front intensity, and may be obtained from the directivity of any position (angle). That is, gains may be obtained from other angle values of the same simulation result, and the gains may be compared and used to evaluate the gain improvement effect.

<Consideration of the first simulation>
Comparing condition 1 (without grooves) with conditions 2 and 3 (with grooves), conditions 2 and 3 (with grooves) have a higher gain. Further, when the conditions 2 and 3 (one groove) and the conditions 4 and 5 (two grooves) are compared, the conditions 4 and 5 have a higher gain. Even if the conditions 2 and 3 and the conditions 4 and 5 are compared, the gain is almost the same.

  From the first simulation result, providing the groove 40 on the side of the slot antenna 20 (near the surface of the slot) is effective in improving the gain, and two grooves 40 are more than one. It turns out that an effect is high. It has been found that there is no difference in gain improvement effect even if the groove 40 is formed on the + x side or the −x side of the slot antenna 20.

<< Second simulation >>
The second simulation is a simulation for confirming a shape effective for improving the gain of the groove 40 provided on the side of the slot antenna 20 in response to the first simulation result. That is, from the first simulation, it was verified that providing the groove 40 on the side of the slot antenna 20 has an effect of improving the gain. Therefore, the positional relationship and shape of the groove 40 with the slot antenna 20 were further studied by focusing on a specific antenna model.

<Second simulation condition>
In the second simulation, the following conditions 6 to 10 were applied. Conditions 6 and 7 and conditions 8 and 10 are a condition in which the position is changed using the same antenna model and a condition in which the depth of the groove 40 is changed. Condition 9 is a condition in which the depth of the groove 40 of the antenna model used in the simulations of conditions 2 and 3 is changed.
Condition 6) This is a simulation in which the position of the groove 40 is variously changed using an antenna model in which two grooves 40 are provided on both sides of the slot antenna 20 in the x direction.
Condition 7) This is a simulation in which the depth of the groove 40 is changed variously using an antenna model in which two grooves 40 are provided on both sides of the slot antenna 20 in the x direction.
Conditions 8 and 10) This is a simulation in which the depth of the groove 40 is variously changed using an antenna model in which one groove 40 is provided on each side of the slot antenna 20 in the x direction.
Condition 9) This is a simulation in which the position of the groove 40 is changed variously using an antenna model in which one groove 40 is provided on each side of the slot antenna 20 in the x direction.

  In the antenna models used in the simulations of conditions 4 and 5, when two grooves are installed on both sides (conditions 6 and 7), the distance and depth from the slot antenna are changed. The antenna model used in the simulation of condition 8 is obtained by changing the depth of the groove 40 of the antenna model of conditions 2 and 3. In the antenna model used in the simulations of the conditions 9 and 10, the distance and depth from the slot antenna of the groove 40 of the antenna model in which the width of the groove 40 of the antenna model in the conditions 2 and 3 is changed (widened) are changed. It is a thing.

  10 to 12 are schematic views of the antenna model used in the simulation of conditions 6 and 7, the antenna model used in the simulation of condition 8, and the cross section of the antenna model used in the simulation of conditions 9 and 10. Referring to FIG. 10, in the antenna model used in the simulations of conditions 6 and 7, two grooves 40 with an interval of 0.3 mm (≈0.08λ) are provided on both sides of the slot antenna 20 in the x direction. Yes. The center line M1 of the two grooves 40 is separated from the center line C of the slot antenna 20 by a distance X. The distance X corresponds to the distance indicated by the distance l (ie, L1 / 2) in FIG. 2, which is an example in the case where a plurality of slot antennas 20 are included, for example, and two waveguides adjacent to the distance X. The distance L1 between the 11 center lines Cw in the longitudinal direction of the tube satisfies L1 = 2X. Each of the grooves 40 has a width of 0.3 mm (≈0.08λ) and a depth Y. In condition 6, the depth Y is fixed to 1 mm (≈0.26λ≈1 / 4λ), which is deeper than the depth from the slot surface to the hollow of the waveguide 11, and the distance X is a variable (two grooves Simulations were performed at various distances X (with 40 intervals maintained).

  Under condition 7, the distance X was fixed at 1.93 mm (≈0.49λ), and the simulation was performed at various depths Y with the depth Y as a variable. The wall thickness m between the groove 40 on the side close to the waveguide 11 and the hollow of the waveguide 11 of the antenna model in which the distance X is fixed to 1.93 mm is 0.21 mm (≈0.05λ). .

  Referring to FIG. 11, the antenna model used in the simulation of condition 8 is 0.21 mm (= ≈0.05λ≈1 / 20λ) apart from the hollow of waveguide 11 on both sides in the x direction of slot antenna 20. One groove 40 is provided. Each of the grooves 40 has a width of 0.3 mm (≈0.08λ) and a depth Y. In condition 8, the simulation was performed at various depths Y with the depth Y as a variable.

  Referring to FIG. 12, the antenna model used in the simulations of conditions 9 and 10 is provided with one groove 40 on both sides of the slot antenna 20 in the x direction. The center line M2 of the groove 40 is separated from the center line C of the slot antenna 20 by a distance X. Each of the grooves 40 has a width of 1 mm (≈0.26λ≈1 / 4λ) and a depth Y. In condition 9, the depth Y is fixed at 1 mm (≈0.26λ≈1 / 4λ), which is deeper than the depth from the slot surface to the hollow of the waveguide 11, and the distance X is a variable. A simulation was performed.

  Under condition 10, the distance X was fixed to 1.93 mm (≈0.49λ), and the simulation was performed at various depths Y with the depth Y as a variable. In the antenna model in which the distance X is fixed to 1.93 mm, the wall thickness m between the groove 40 on the side close to the waveguide 11 and the hollow of the waveguide 11 is 0.16 mm (≈0.04λ). .

  <Second simulation result>

  In FIG. 13A, the distance X, which is a variable under condition 6 (changing the groove position), is 0.49λ (≈1.92 mm), 0.50λ (= 1.96 mm), 0.60λ (≈2.35 mm). ), 0.70λ (≈2.74 mm), and a list showing the gains obtained from the respective simulation results. In the antenna model having a distance X of 0.49λ (≈1.92 mm), the wall thickness m between the groove 40 near the waveguide 11 and the hollow of the waveguide 11 is 0.20 mm (≈0. 05λ). The wall thickness m between the groove 40 on the side close to the waveguide 11 and the hollow of the waveguide 11 of the antenna model with the distance X of 0.50λ (= 1.96 mm) is 0.24 mm (≈0. 06λ). The wall thickness m between the groove 40 on the side close to the waveguide 11 and the hollow of the waveguide 11 of the antenna model with the distance X of 0.60λ (≈2.35 mm) is 0.63 mm (≈0. 16λ). The wall thickness m between the groove 40 on the side close to the waveguide 11 and the hollow of the waveguide 11 of the antenna model having the distance X of 0.70λ (≈2.74 mm) is 1.02 mm (≈0. 26λ).

  In condition 6, the distance X is added to the above value, and further changed to 1.30λ (≈5.10 mm) and 1.80λ (≈7.06 mm), and the gain obtained from the simulation result is changed. This is also shown in FIG. The wall thickness m between the groove 40 on the side close to the waveguide 11 and the hollow of the waveguide 11 of the antenna model with the distance X of 1.30λ (≈5.10 mm) is 3.38 mm (≈0. 86λ). In the antenna model with the distance X of 1.80λ (≈7.06 mm), the wall thickness m between the groove 40 near the waveguide 11 and the hollow of the waveguide 11 is 5.34 mm (≈1. 36λ). In the first row of the table in FIG. 13A, the gain obtained from the simulation result under the condition (condition 1) in which no groove is provided is entered as a reference. The same applies to the simulation results thereafter.

  FIG. 13B shows the depth Y as a variable in condition 7 (changing the groove depth), 0.20λ (≈0.78 mm), 0.26λ (≈1.02 mm), 0.31λ (≈1). .22 mm), 0.36λ (≈1.41 mm), 0.41λ (≈1.61 mm), 0.46λ (≈1.80 mm), 0.51λ (≈2.00 mm), It is the list showing the gain obtained from each simulation result.

  FIG. 14 shows the depth Y as a variable under condition 8 (change of groove depth), 0.20λ (≈0.78 mm), 0.26λ (≈1.02 mm), 0.31λ (≈1.22 mm). , 0.36λ (≈1.41 mm), 0.41λ (≈1.61 mm), 0.46λ (≈1.80 mm), 0.51λ (≈2.00 mm) It is the list showing the gain obtained from.

  In FIG. 15A, the distance X, which is a variable in condition 9 (changes the groove position), is 0.52λ (≈2.034 mm), 0.62λ (≈2.43 mm), 0.72λ (≈2.82 mm). ) Is a list showing gains obtained from the respective simulation results. The wall thickness m between the groove 40 and the hollow of the waveguide 11 of the antenna model with the distance X of 0.52λ (≈2.034 mm) is 0.27 mm (≈0.07λ). The wall thickness m between the groove 40 and the hollow of the waveguide 11 of the antenna model with the distance X of 0.62λ (≈2.43 mm) is 0.66 mm (≈0.17λ). The wall thickness m between the groove 40 and the hollow of the waveguide 11 of the antenna model with the distance X of 0.72λ (≈2.82 mm) is 1.05 mm (≈0.27λ).

  In condition 9, the distance X is added to the above value and further changed to 1.32λ (≈5.17 mm) and 1.82λ (≈7.13 mm), and the gain obtained from the simulation result is changed. This is also shown in FIG. The wall thickness m between the groove 40 and the hollow of the waveguide 11 of the antenna model with the distance X of 1.32λ (≈5.17 mm) is 3.40 mm (≈0.87λ). The wall thickness m between the groove 40 and the hollow of the waveguide 11 of the antenna model with the distance X of 1.82λ (≈7.13 mm) is 5.36 mm (≈1.37λ).

  In FIG. 15B, the depth Y, which is a variable under condition 10 (changing the groove depth), is 0.15λ (≈0.59 mm), 0.20λ (≈0.78 mm), 0.26λ (≈1). .02mm), 0.31λ (≈1.22mm), 0.36λ (≈1.41mm), 0.41λ (≈1.61mm), 0.46λ (≈1.80mm), 0.51λ (≈2) .00 mm) is a list showing gains obtained from the respective simulation results.

<Consideration of second simulation>
Here, it considers from a viewpoint of the occupation width (required area) of an antenna. The antenna occupation width refers to the width including the slot surface 11a and the groove 40 portion. For example, in the case of the antenna model of FIG. 12, the antenna occupation width is the width of a region including the waveguide 11 and a total of two grooves 40 respectively arranged on both sides thereof. Specifically, the width in the + x direction from the center line C of the waveguide 11 is the distance X and half the length of the groove 40 (1 mm / 2 = 0.5 mm in the figure), and this width is from the center line C. It is also required for the -x direction. Therefore, the occupied width of the antenna in this antenna model can be considered as occupied width = 2 × distance X + width of the groove 40. As shown in FIG. 10, the antenna occupation width in the case of the antenna model in which the plurality of grooves 40 are arranged on both sides of the waveguide 11 is a width including the slot surface 11a and all the groove 40 portions. That is, the occupied width may be considered in the same manner as the antenna model of FIG. 12 with the groove 40 farthest from the waveguide 11 as a target.

  In the antenna model used in the simulations of conditions 4 and 5, when two grooves are installed on both sides (conditions 6 and 7), the position of the groove 40 is the value simulated for the above-mentioned distance X in the vicinity of the waveguide 11. It can be seen that there is an effect of gain improvement. In particular, in the range of the distance X ≦ 0.7λ, in other words, in the range where the wall thickness m is 1.02 mm (≈0.26λ) or less, the antenna occupation width is not increased, and the gain improvement effect is also high. It was confirmed that it was preferable. In particular, it was confirmed that the effect of gain improvement is maximized at X = 0.6λ. In other words, it was confirmed that the effect of gain improvement is maximized when the wall thickness m between the groove 40 near the waveguide 11 and the hollow of the waveguide 11 is 0.63 mm (≈0.16λ). .

  Under condition 7, it was confirmed that there is an effect of improving the gain when the depth Y of the groove 40 is in the range of Y ≦ 0.51λ. In particular, it has been confirmed that the gain improvement effect is maximized at Y = 0.26λ.

  In the antenna model used in the simulations of conditions 2 and 3, when one groove is provided on both sides (condition 8), the gain improvement effect is obtained when the depth Y of the groove 40 is in the range of Y ≦ 0.51λ. Was confirmed. In particular, it has been confirmed that the gain improvement effect is maximized at Y = 0.26λ.

  In the case of an antenna model (one groove) in which the width of the groove 40 of the antenna model used in the simulations of conditions 2 and 3 is wide (conditions 9 and 10), each value simulated with the position of the groove 40 being in the vicinity of the waveguide 11 It can be seen that there is an effect of improving the gain. In particular, in the range of the distance X ≦ 0.72λ, in other words, in the range where the wall thickness m is 1.05 mm (≈0.27λ) or less, the antenna occupation width is not increased, and the gain improvement effect is also high. It was confirmed that it was preferable. In particular, it was confirmed that the effect of gain improvement is maximized when X = 0.52λ. That is, it has been confirmed that the effect of gain improvement is maximized particularly when the wall thickness m between the groove 40 and the hollow of the waveguide 11 is 0.27 mm (≈0.07λ).

  Under condition 10, it was confirmed that there is an effect of improving the gain when the depth Y of the groove 40 is in the range of Y ≦ 0.51λ. In particular, it has been confirmed that the gain improvement effect is maximized at Y = 0.26λ.

  Therefore, with respect to the wall thickness m between the slot antenna 20 and the groove 40, it is preferable that m ≦ 0.27λ is set in order to improve the gain based on the simulation results of the conditions 6 and 9. Based on the simulation result, the gap L1 between the adjacent slot antennas 20 is about 2.0λ as described above, preferably 1.5λ or less, more preferably 1.2λ or less, for example, 1.0λ or less, and gain. It is because it is thought that it improves. Thereby, both improvement in gain and ease of manufacture can be achieved.

  Further, regarding the depth Y of the slot antenna 20, it is preferable that the depth Y is about Y ≦ 0.51λ from the simulation results of the conditions 8 and 10. Preferably, the depth Y is about 0.15λ ≦ Y ≦ 0.51λ. This is because, based on the simulation result, it is considered that the gain is improved more effectively by providing the groove 40 having this depth.

  Further, when the condition 8 and the condition 10 are compared, the condition 10 generally has a larger gain value. Therefore, when one groove 40 is provided on the side of the slot antenna 20, it can be understood that the wider one has the effect of improving the gain.

<< Third simulation >>
The third simulation is a simulation for confirming the effect when the metal plate 50 is provided in addition to the groove 40 on the side of the slot antenna 20 in response to the first and second simulation results. That is, it is verified by the first simulation that the groove 40 is provided on the side of the slot antenna 20 to improve the gain, and the second simulation confirms the position and shape of the groove 40 having a high gain improvement effect. It was done. Therefore, the effect of further providing the metal plate 50 was simulated.

<Third simulation condition>
In the third simulation, the same antenna model as that used in the simulations in conditions 2 and 3 was used, and the simulation was performed by applying the conditions 11 and 12 in which the positions and shapes of the metal plates 50 were changed.

  FIG. 16 is a schematic diagram of a cross section of the antenna model used in the simulation of condition 11. FIG. 17 is a schematic diagram of a cross section of the antenna model used in the simulation of condition 12. With reference to FIG. 16 and FIG. 17, the metal plate 50 is provided above the groove 40 provided on the side of the slot antenna 20 in both the antenna models of the conditions 11 and 12. Referring to FIG. 16, in the antenna model used in the simulation of condition 11, the metal plate 50 has a width of 0.5 mm (≈0.13λ) and a height (length in the front-rear direction) of 0.98 mm (≈ 0.25λ) (vertically long shape), and the center line M4 is spaced from the center line M3 of the groove 40 by 0.3 mm (≈0.08λ). Referring to FIG. 17, in the antenna model used in the simulation of condition 12, the shape of the metal plate 50 is 1 mm in width (≈ (1/4) λ) and 0.2 mm in height (≈0.05λ). (Horizontal shape), the center line M5 is spaced from the center line M3 of the groove 40 by 0.3 mm (≈0.08λ).

<Third simulation result>
FIG. 18 is a list showing gains obtained from the simulation results of the conditions 11 and 12.

<Consideration of third simulation>
There is no great difference in the gains obtained from the simulation results of the conditions 11 and 12, and both gains are larger than those in the case where only the groove 40 is provided (conditions 2 and 3). Therefore, it can be seen from this simulation result that providing the metal plate 50 in addition to the groove 40 on the side of the slot antenna 20 has an effect of improving the gain.

<< 4th simulation >>
From the first to third simulations, it was confirmed that the gain is improved by disposing the groove 40 on at least one side of the slot antenna 20. Therefore, by combining this antenna model, it is presumed that the effect of improving the gain can be obtained in the antenna in which the plurality of slot antennas 20 are arranged in parallel and the groove 40 is provided between the slot antennas 20. Therefore, a fourth simulation was performed using an antenna model in which a plurality of (for example, two or four) slot antennas 20 are included, and one or more recesses such as a groove 40 are provided therebetween.

<Fourth simulation condition>
In the fourth simulation, the following conditions 13 to 24 were applied for the simulation.
Condition 13) An antenna model in which two slot antennas 20A and 20B are provided in parallel without a groove 40, with their respective centers C separated by 3.85 mm (≈λ) (with an interval of 1.31 mm (≈0.33λ)). It is the simulation used.
Condition 14) The four slot antennas 20A, 20B, 20C, and 20D without the groove 40 are parallel to each other with the center C separated by 3.85 mm (≈λ) (with an interval of 1.31 mm (≈0.33λ)). This is a simulation using the antenna model.
Condition 15) This is a simulation using an antenna model in which two grooves 40 and a metal plate 50 are provided between two parallel slot antennas 20A and 20B.
Condition 16) A simulation using an antenna model in which two grooves 40 are provided between two parallel slot antennas 20A and 20B and on the side where no other slot antenna is adjacent in the x direction.
Conditions 17 and 23) A simulation using an antenna model in which two grooves 40 are provided between two parallel slot antennas 20A and 20B.
Condition 18) Antenna model in which two grooves 40 and two metal plates 50 are provided between each of the four parallel slot antennas 20A, 20B, 20C, and 20D and on the side where no other slot antenna is adjacent in the x direction. This is a simulation using
Conditions 19 to 22) A simulation using an antenna model in which one groove 40 is provided between two parallel slot antennas 20A and 20B.
Condition 24) An antenna model in which a metal plate 50 is provided without a groove 40 between each of the four slot antennas 20A, 20B, 20C, and 20D arranged in parallel and on the side where no other slot antenna is adjacent in the x direction. It is the simulation used.

  19 to 28 are schematic views of cross sections of the antenna model used in the simulations of conditions 15 to 24. FIG. Referring to FIG. 19, the antenna model used in the simulation of condition 15 is provided with a first groove 40 spaced 0.26 mm (≈0.07λ) in the + x direction from slot antenna 20A, and further 0.4 mm ( A second groove 40 is provided at a distance of ≈0.10λ. Each of the grooves 40 has a width of 0.2 mm (≈0.05λ) and a depth of 1.2 mm (≈0.31λ). Further, a metal plate 50 is provided immediately above the two grooves 40 at a position spaced 0.5 mm (≈0.13λ) in the front direction from the surface of the substrate 10. The metal plate 50 has a length in the front direction of 0.98 mm (≈0.25λ) and a length in the width direction of 0.5 mm (≈0.13λ).

  Referring to FIG. 20, the antenna model used in the simulation of condition 16 is based on the slot antennas 20A and 20B between the two slot antennas 20A and 20B and on the side where no other slot antenna is adjacent in the x direction. A groove 40 having the same positional relationship as the antenna model used in the simulation of condition 4 is provided. The width and depth of the groove 40 are the same as those in the conditions 2 and 3.

  Referring to FIG. 21, the antenna model used in the simulation of condition 17 is the antenna model used in the simulation of condition 16 except for the two grooves 40 on both sides of the two slot antennas 20A and 20B. It is. That is, in the antenna model used in the simulation of condition 17, two grooves 40 are provided between the slot antennas 20A and 20B. The positional relationship of the groove 40 with respect to the slot antennas 20A and 20B, and the width and depth are both common to the condition 16.

  Referring to FIG. 22, the antenna model used in the simulation of condition 18 is for each of the four slot antennas 20A to 20D and to the slot antennas 20A to 20D on the side where no other slot antenna is adjacent in the x direction. The groove 40 having the same positional relationship as that of the antenna model used in the simulation of the condition 4 is provided. The width and depth of the groove 40 are the same as those in the conditions 2 and 3. Further, the metal plates 50 are respectively provided immediately above the two grooves 40. The position and size of the metal plate 50 are the same as those in the condition 15.

  23 to 26, in each of the antenna models used in the simulations of the conditions 19 to 22, one groove 40 is provided between the two slot antennas 20A and 20B. Condition 19 and condition 20 have the same width of the groove 40 of 1 mm (≈ (1/4) λ), and the depth is 1.2 mm (≈ (3/10) λ), 1 mm (≈ (1/4) λ ) Is different. Conditions 20 to 22 have a common groove depth of 1 mm (≈ (1/4) λ), a width of 1 mm (≈ (1/4) λ), 0.3 mm (≈0.08λ), 0 .5 mm (≈0.13λ). In any condition, the center line of the groove 40 coincides with the center of the slot antennas 20A and 20B.

  The antenna model used in the simulation of condition 23 shown in FIG. 27 is obtained by removing the metal plate 50 provided between the two slot antennas 20A and 20B from the antenna model used in the simulation of condition 15. . That is, in the antenna model used in the simulation of condition 23, two grooves 40 are provided between the slot antennas 20A and 20B. The positional relationship of the groove 40 with respect to the slot antennas 20A and 20B, and the width and depth are the same as those in the condition 15.

  Referring to FIG. 28, the antenna model used in the simulation of condition 24 is a front view from the surface of substrate 10 between each of the four slot antennas 20A to 20D and on the side where no other slot antenna is adjacent in the x direction. A metal plate 50 is provided separated in the direction.

  Referring to FIG. 28, in the antenna model used in the simulation of condition 24, metal plate 50 is provided at a position spaced 0.3 mm (≈0.08λ) in the front direction from the surface of substrate 10. The length of the metal plate 50 in the front direction is 0.2 mm (≈0.05λ), and the length in the width direction is 1 mm (≈ (¼) λ). The center line of the metal plate 50 coincides with the center of the adjacent slot antenna 20.

<Fourth simulation result>
FIG. 29 is a list showing the maximum value of the gain for each slot antenna under each condition of the gains obtained from the simulation results of the above conditions 13 to 24. FIG. 30 is a list showing gains obtained from simulation results under conditions 13 to 26.

<Consideration of the fourth simulation>
In the case of an antenna model in which a plurality of slot antennas 20 are arranged in parallel, it is more effective to improve gain when the groove 40 is provided between the slot antennas 20 than when the slot antenna 20 is not provided (conditions 13 and 14). I understand that. In addition, the groove 40 is provided only between the slot antennas 20 (condition 17), and the groove 40 is provided between the slot antennas 20 and both sides of the plurality of slot antennas 20 (condition 16). Is high. In addition, when the metal plate 50 is combined with the groove 40 (conditions 15 and 18), it can be seen that there is an effect of improving the gain.

<< Fifth simulation >>
In the fourth simulation, for the antenna model having a plurality of slot antennas 20 arranged in parallel, the grooves 40 are provided between the slot antennas 20, but the fifth simulation is performed for other variations of the grooves 40. went. Specifically, a fifth antenna for confirming gain improvement using an antenna model in which a plurality of slot antennas 20 each provided with a groove 40 on each side is arranged without sandwiching the groove 40 therebetween. A simulation was performed.

<Fifth simulation condition>
In the fifth simulation, the following conditions 25 and 26 were applied for the simulation.
Condition 25) The two slot antennas 20A and 20B are arranged in parallel with their respective centers C separated by 3.85 mm (≈0.98λ), and no groove 40 is provided between them, so that they are not adjacent to the other slot antenna in the x direction. This is a simulation using an antenna model in which two grooves 40 are provided on each side.
Condition 26) Four slot antennas 20A, 20B, 20C, and 20D are arranged in parallel with their respective centers C separated by 3.85 mm (≈0.98λ), and between the slot antennas 20A and 20B and between the slot antennas 20C and 20D. An antenna model in which two grooves 40 are provided between the slot antennas 20B and 20C and the slot antennas 20A and 20D on the side not adjacent to the other slot antenna in the x direction and the slot antennas 20B and 20C is used. It is a simulation.

  31 and 32 are schematic views of the cross section of the antenna model used in the simulations of conditions 25 and 26. FIG. Referring to FIG. 31, the antenna model used in the simulation of the strip 27 is provided with a first groove 40 separated from the slot antenna 20A by 0.21 mm (≈0.05λ≈1 / 20λ) in the −x direction. Further, a second groove 40 is provided at a distance of 0.3 mm (≈0.08λ). Further, a first groove 40 is provided 0.21 mm (≈0.05λ≈1 / 20λ) apart from the slot antenna 20B in the positive direction, and a second groove 40 is further separated by 0.3 mm (≈0.08λ). Is provided. The width and depth of the groove 40 are the same as those in the conditions 2 and 3. Referring to FIG. 32, the antenna model used in the simulation of condition 26 has a shape in which two antenna models used in the simulation of condition 25 are arranged in the x direction.

<Fifth simulation result>
FIG. 33 is a list showing gains obtained from the simulation results of the conditions 25 and 26, respectively.

<Consideration of fifth simulation>
It was confirmed that there was no significant difference in the gain improvement effect under both conditions 25 and 26. In both conditions 25 and 26, it was confirmed that the gain was larger than in the case where two grooves 40 were provided on each side of each slot antenna 20 (conditions 4 and 5). Also, the gain improvement effect is higher than when two slot antennas 20 are arranged in parallel without providing the groove 40 (condition 13) and when four slot antennas 20 are arranged in parallel without providing the groove 40 (condition 14). It was confirmed. Therefore, it can be seen from this simulation result that the groove 40 is not provided on both sides of the slot antenna 20 but is provided on at least one side, and thus it is effective in improving the gain.

[Second Embodiment]
As defined above, the antenna system is composed of one or more groups of arranged slot antennas. In the first embodiment, one antenna system is composed of one slot antenna. An example is shown. Therefore, in the case of a receiving antenna system, the angle of the object to be detected with respect to the antenna 100 is calculated based on the phase difference of the received radio wave for each slot antenna as the phase difference of the radio wave received for each antenna system. Is done.

  As another example, one antenna system may be configured by a plurality of slot antennas. As an example of the antenna 100 according to the second embodiment, FIG. 34 is an example of the antenna system for transmission of the antenna 100, and an example of the configuration of the antenna system for transmission composed of three slot antennas. FIG. In the example of FIG. 34, one antenna system for transmission is composed of three slot antennas 20E, 20F, and 20G. The three slot antennas 20E, 20F, and 20G have waveguides 11E, 11F, and 11G, respectively, and are arranged so that the longitudinal directions of the waveguides 11E, 11F, and 11G are parallel to each other. The three slot antennas 20E, 20F, and 20G constituting one transmission antenna system share one feed line extending from the transmitter 150.

  The inventors simulate the intensity directivity of the slot antenna 20 under various conditions in which the groove 40 that is the recess is changed using a part of the antenna 100 according to the second embodiment, and thereby design the antenna 100. The effect of was verified.

<< Sixth simulation >>
The sixth simulation is a simulation for confirming the presence or absence of a groove on the side of the slot antenna 20 by using a transmission antenna system composed of three slot antennas 20.

<Sixth simulation condition>
In the sixth simulation, the following conditions 27 to 30 were applied for the simulation.
Condition 27) A simulation using an antenna model that is one antenna system in which the three slot antennas 20E, 20F, and 20G are arranged in parallel with the center C separated by 3.85 mm (≈0.92λ) without providing the groove 40. It is.
Condition 28) An antenna model in which two grooves 40 are provided between three parallel slot antennas 20E, 20F, and 20G, and one groove is provided on the side where no other slot antenna is adjacent in the x direction. This is a simulation using
Condition 29) This is a simulation using an antenna model in which two grooves 40 are provided between three parallel slot antennas 20E, 20F, and 20G.
Condition 30) This is a simulation using an antenna model in which one groove is provided on the side of the three slot antennas 20E, 20F, 20G arranged in parallel in the x direction where no other slot antenna is adjacent.

  35 to 37 are schematic views of the cross section of the antenna model used in the simulations of conditions 28 to 30. FIG. Referring to FIG. 35, in the antenna model used in the simulation of condition 28, the first groove 40 is provided in the + x direction by 0.23 mm (≈0.06λ) from slot antenna 20E, and 0.2 mm ( A second groove 40 is provided with a distance of approximately 0.05λ. Similarly, two grooves 40 are provided in a region adjacent to the slot antenna 20F in the + x direction. Further, one groove 40 is provided at a distance of 0.23 mm (≈0.06λ) from the slot antenna 20E in the −x direction and from the slot antenna 20G in the + x direction. Each of the grooves 40 has a width of 0.2 mm and a depth of 1.2 mm (≈0.31λ).

  Referring to FIG. 36, the antenna model used in the simulation of condition 29 is the same as the antenna model used in the simulation of condition 28 except for one groove 40 on each of the three slot antennas 20E, 20F, and 20G sides. It is a thing. That is, in the antenna model used in the simulation of condition 31, two grooves 40 are provided between the slot antennas 20E and 20F and between the slot antennas 20F and 20G. The positional relationship, width, and depth of the groove 40 with respect to the slot antennas 20E, 20F, and 20G are the same as those in the condition 30.

  Referring to FIG. 37, the antenna model used in the simulation of condition 30 has two grooves provided between the slot antennas 20E and 20F and between the slot antennas 20F and 20G from the antenna model used in the simulation of condition 28. Is excluded. That is, the antenna model used in the simulation model of condition 30 is provided with one groove 40 on each side of the three slot antennas 20E, 20F, and 20G. The positional relationship, width, and depth of the groove 40 with respect to the slot antennas 20E, 20F, and 20G are common to the condition 28.

<Sixth simulation result>
FIG. 38 is a list showing gains obtained from the simulation results of Condition 27 to Condition 30.

<Consideration of the sixth simulation>
Even in the case where one antenna system is composed of a plurality of slot antennas, as in the case where the antenna system is composed of one slot antenna, the one in which a groove is provided between the slot antennas (conditions 28 and 29) is the slot. It was confirmed that there is an effect of improving the gain compared to the case where there is no groove between the antennas (conditions 27 and 29). Further, it was confirmed that the effect was more effective than the case (condition 29) in which no groove (condition 28) was provided on both sides of the parallel slot antenna group.

[Third Embodiment]
The manufacturing method of the antenna 100 mounted on the radar 300 is not limited to a specific manufacturing method. As considered from the previous simulation results, by reducing the distance X (or wall thickness m), both gain improvement and antenna miniaturization can be achieved. However, if the distance X (or wall thickness m) is reduced, it may be difficult to cut and form the groove 40 from the surface of the substrate 10. Therefore, the antenna 100 is preferably manufactured by a manufacturing method in which a plurality of plates called diffusion bonding or heat pressure welding are stacked and further pressure-bonded. That is, preferably, the substrate 10 has a laminated structure in which a plurality of plates are laminated. In addition, the board in a state before lamination is also referred to as a laminated board in the following description.

  FIG. 39 is a diagram for explaining an example of a method for manufacturing the antenna 100. FIG. 39A is a view showing a laminated plate in a schematic view of a cross section in which the antenna 100 is cut along a plane in which the tube longitudinal direction of the waveguide is orthogonal. FIG. 39B is a diagram for explaining the shape of each laminated plate, and is a view of each laminated plate as viewed from the front direction of the antenna 100.

  Referring to FIG. 39A, when groove 40 is provided between adjacent slot antennas 20A and 20B, antenna 100 has laminated plates T1 to T4 parallel to the surface of substrate 10 in that order. And further formed by pressure contact. The thickness of each laminate is determined so that the cross sections of the surfaces parallel to the surface of the substrate 10 have the same shape. Specifically, referring to FIG. 39A, the thickness of the laminated plate T1 is the length Th1 in the front direction of the antenna 100 from the bottom surface of the substrate 10 to the bottom surface of the waveguide 11. The thickness of the laminated plate T <b> 2 is the length Th <b> 2 in the front direction of the antenna 100 from the bottom surface of the waveguide 11 to the bottom surface of the groove 40. The thickness of the laminated plate T3 is the length Th3 in the front direction of the antenna 100 from the bottom surface of the groove 40 to the bottom surface of the slot element 12. The thickness of the laminated plate T4 is the length Th4 in the front direction of the antenna 100 from the bottom surface of the slot element 12 to the surface of the substrate 10. In addition, thickness Th3, Th4, etc. of laminated board T3, T4 etc. may be implement | achieved so that a thin board of the same shape may be piled up and it may become required thickness.

  By setting the thicknesses Th1 to Th4 of the laminated plates T1 to T4 in this way, the laminated plates T1 to T4 have a shape as shown in FIG. That is, the laminated plate T1 is a plate that has not been subjected to hole machining. The laminated plate T2 has through holes H1 and H2. The through holes H1 and H2 have a cross-sectional shape (rectangular shape) in a plane parallel to the surface of the substrate 10 of each of the waveguides 11A and 11B. The laminated plate T3 has through holes H1 and H2 and a through hole H3. The through hole H <b> 3 has a cross-sectional shape (rectangular shape) in a plane parallel to the surface of the substrate 10 of the groove 40. The laminated plate T4 has a through hole H3 and a plurality of through holes H4. The through hole H <b> 4 has a cross-sectional shape (rectangular shape) in a plane parallel to the surface of the substrate 10 of the slot element 12.

  The through holes H1 and H2 of the laminated plate T2 are closed by the laminated plate T1 in the back direction. Further, the through holes H1 and H2 of the laminated plate T2 communicate with the through holes H1 and H2 of the laminated plate T3 in the front direction. The through hole H3 of the laminated plate T3 is closed by the laminated plate T2 in the back direction. Further, the through hole H3 of the laminated plate T3 communicates with the through hole H3 of the laminated plate T4 in the front direction.

  As shown in FIG. 39B, a complex element such as the slot element 12 or the groove 40 is laminated by adopting a manufacturing method of the antenna 100, which is called diffusion bonding, in which a laminated plate is pressure-bonded. The plate can be formed as a through hole. Therefore, it can be manufactured more easily than cutting them out from the surface of the substrate 10. In particular, when the wavelength of the operating frequency of the antenna 100 is a small wavelength such as a millimeter wave, it is very difficult to cut out the groove 40. Therefore, by adopting such a manufacturing method, it is possible to facilitate the formation of the antenna, particularly when the wavelength of the operating frequency is small.

[Fourth Embodiment]
In the first to third embodiments, the one or more recesses formed on the surface of the substrate 10 between the adjacent slot antennas 20 extend in the longitudinal direction of the waveguide 11. One or more grooves 40 are illustrated. The groove 40 may be formed in a region adjacent to the slot surface of the slot antenna 20 in the x direction on the surface of the substrate 10 and adjacent to the slot element 12 of the slot antenna 20 in the x direction. That is, the groove 40 extending in the tube longitudinal direction of the waveguide 11 may be interrupted in the tube longitudinal direction. In other words, two or more grooves 40 extending in the tube longitudinal direction of the waveguide 11 may be provided in parallel in the tube longitudinal direction across the partition wall. The partition wall portion does not exist at the position where the slot element 12 of the slot antenna 20 adjacent in the width direction (x direction) is formed, and exists at the position where the slot element 12 is not formed.

  As described in the first to third embodiments, since the groove 40 has an effect of improving the gain, the groove is necessary in the slot element 12 portion that radiates radio waves. In order to reduce the influence of the partition wall, the strength in the longitudinal direction of the antenna tube can be prevented by providing the partition wall in a portion where the slot element 12 that radiates radio waves is not present.

FIG. 40 is a view for explaining another example of the groove 40 provided between the adjacent slot antennas 20. Referring to FIG. 40, in the slot antenna 20, the slot element 12 is guided directly above or substantially directly above each of the two straight lines C _SL and C _SR parallel to each other with the center line Cw of the slot antenna 20 interposed therebetween. The tubes 11 are arranged at regular intervals in the longitudinal direction of the tube 11 or at substantially regular intervals with some errors (for example, about 10% of the average interval). The slot elements 12 arranged on the straight line C _SL, the width direction position of the slot elements 12 arranged on a straight line C _SR does not match. As shown in FIG. 40, the straight lines H _T and H _B are the straight lines perpendicular to the tube longitudinal direction, which are in contact with both ends in the tube longitudinal direction of each slot element 12, respectively. Referring to FIG. 40, a region extending in the width direction and continuous in the longitudinal direction of the tube, which is divided by adjacent straight lines H _T and H _{B on} the surface of the substrate 10, includes a region including the slot elements 12. The areas not included are alternated. Note that the region including the slot element 12 and the region not including the slot element 12 are also shown in FIG.

The groove 40 provided between the slot antennas 20A and 20B forms a groove in the region including the slot element 12 in the width direction. The portion of the groove 40 that is interrupted in the longitudinal direction of the tube, that is, the second partition wall portion exists in a region that does not include the slot element 12 in the width direction, and does not exist outside that region. In the example of FIG. 40, the slot element 12 exists in a region between the slot antennas 20A and 20B, which is divided by a straight line H _T and a straight line H _B adjacent to the straight line H _B in FIG. The slot element 12 does not exist in a region partitioned by the straight line H _B and the straight line H _T adjacent below the straight line in FIG. Therefore, the groove 40 is always present in the former region. The interrupted portion of the groove 40 which is the second partition wall portion exists in the latter region and does not exist in a range exceeding the region.

  By providing the location where the groove 40 is interrupted, that is, the second partition wall portion, the strength of the antenna 100 in the longitudinal direction of the tube can be prevented from decreasing.

[Fifth Embodiment]
For example, the member provided at a position having a positive distance in the front direction from the surface of the substrate 10 between the adjacent slot antennas 20 such as the metal plate 50 is also at least from the surface of the substrate 10 at a position adjacent to the slot element 12. May be provided above. In addition, the attachment method with respect to the board | substrate 10 of this member is not limited to a specific method. Therefore, as an example, a support portion for supporting the metal plate 50 against the surface of the substrate 10 may be provided at a position not adjacent to the slot element 12 on the surface of the substrate 10, and the metal plate 50 may be attached to the substrate 10.

  FIG. 41 is a diagram for explaining a method of attaching using the support portion as an example of a method of attaching the metal plate 50 to the substrate 10. 41A is a diagram of the antenna 100 as viewed from the front, and FIG. 41B is a schematic diagram of a cross section of the antenna 100 at the CC position in FIG. 41A.

  Referring to FIG. 41A, the metal plate 50 extending in the tube longitudinal direction of the waveguide 11 does not include the slot 12, and the support for supporting the metal plate 50 with respect to the surface of the substrate 10. A part 50 'is provided. Referring to FIG. 41B, the support portion 50 ′ is a columnar member that extends from the surface of the substrate 10 toward the metal plate 50, for example.

  The position where the support portion 50 ′ is provided is the same as the position of the second partition wall portion provided in the groove 40 described in the fourth embodiment. That is, the support portion 50 ′ is not provided at a position where the slot elements 12 of two adjacent slot antennas are present on either side in the width direction, and is provided at a position where there is no slot element 12 on either side.

The support portion 50 ′ exists in a region that does not include the slot element 12 in the width direction, and does not exist outside that region. In the example of FIG. 41, the slot element 12 exists in the region between the slot antennas 20A and 20B, which is divided by the straight line H _T and the straight line H _B adjacent below the straight line in FIG. The slot element 12 does not exist in a region divided by the straight line H _B and the straight line H _T adjacent below the straight line in FIG. Accordingly, the support portion 50 ′ is provided in the latter area, and is not provided in a range exceeding the area.

  The support portion 50 ′ may be formed integrally with the metal plate 50. By forming in this way, the metal plate 50 can be easily joined to the antenna 100 manufactured by, for example, diffusion bonding.

  The support portion 50 ′ may be formed integrally with the substrate 10. Further, the support portion 50 ′ may be formed integrally with the metal plate 50 and the substrate 10. In this case, the support portion 50 ′ or the support portion 50 ′ and the metal plate 50 can also be manufactured together with the substrate 10 by diffusion bonding. When the support portion 50 ′ or the support portion 50 ′ and the metal plate 50 are manufactured by diffusion bonding together with the substrate 10, the laminated plates T1 to T4 shown in FIG. Laminate sequentially. When the groove 40 is not included, the laminated plates T3 and T4 do not include the through hole H3. Referring to FIG. 41, in the front direction from the laminated plate T1 that forms the surface of the substrate 10, a laminated plate T5 for forming the support portion 50 ′ and a laminated plate T6 for forming the metal plate 50 are provided. Are further laminated. The laminated plate T5 includes a region having a cross-sectional shape in a plane parallel to the surface of the substrate 10 of the support portion 50 'as a region for forming the support portion 50'. In addition, the laminated plate T5 has a hole region having a cross-sectional shape equal to or larger than that of the slot element 12 on a plane parallel to the surface of the substrate 10. This hole region communicates with a through-hole formed in the slot element 12 provided in the laminated plate adjacent to the laminated plate T5 in the back direction. By manufacturing the support portion 50 ′ or the support portion 50 ′ and the metal plate 50 together with the substrate 10 by diffusion bonding, the metal plate is stably supported with respect to the substrate 10, and the antenna 100 having the metal plate is manufactured. Becomes easier.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

DESCRIPTION OF SYMBOLS 10 Board | substrate 10a Board | substrate surface 11,11A-11G Waveguide 11a Slot surface 12 Slot element 20,20A-20G Slot antenna 40,40A-40I Groove 50,50A-50C Metal plate 50 'Support part 100 Antenna 150 Transmitter 170 Reception Machine 300 Radar T1 to T6 Laminated plate H1 to H4 Through hole L1 interval L2 gap m Wall thickness

Claims (12)

A substrate,
One or more hollows provided within the substrate to function as a waveguide;
One or more slot elements penetrating from the one or more cavities to the surface of the substrate for causing the substrate to function as a slot antenna,
An antenna in which one or more grooves extending parallel to the longitudinal direction of the first hollow tube are formed in the vicinity of a slot surface defined below in a first hollow of the one or more hollows.
Slot surface: the surface on which the hollow is projected onto the substrate surface The one or more grooves are formed on the surface of the substrate at a position sandwiching the surface of the first hollow slot, and each include two grooves extending parallel to the longitudinal direction of the first hollow tube. Item 10. The antenna according to Item 1. The one or more hollows further include a second hollow provided so that a longitudinal direction of the tube is parallel to the first hollow,
Of the one or more grooves, a groove formed on the substrate surface between the first hollow slot surface and the second hollow slot surface includes the first hollow and the first hollow. The antenna according to claim 2, wherein the antenna is evenly spaced from the second hollow. The antenna according to claim 3, wherein the first hollow and the second hollow are connected to a common feeder line. The one or more hollows further include a second hollow provided so that a longitudinal direction of the tube is parallel to the first hollow,
The one or more grooves are formed on the substrate surface at positions sandwiching the first hollow and the second hollow slot surfaces, and each extend in parallel with the longitudinal direction of the first hollow tube 2. Including a groove in the book,
No groove is formed between the first hollow slot surface and the second hollow slot surface;
The antenna according to claim 1. The one or more slot elements include a plurality of slot elements arranged along a longitudinal direction of the hollow tube;
The one or more grooves include two grooves that are adjacent to each other in the longitudinal direction of the tube via a partition wall and extend in the longitudinal direction of the tube,
The partition wall is not formed at a position where any one of the plurality of first hollow slot elements is provided in a direction orthogonal to the traveling direction of the electromagnetic wave as viewed from the partition wall. 6. The device according to claim 1, wherein the first hollow slot elements are not provided in a direction perpendicular to the traveling direction of the electromagnetic wave when viewed from the portion. Antenna. Of the one or more grooves, the wall thickness that is the distance from the wall surface facing the first hollow of the groove closest to the first hollow to the wall surface facing the closest groove of the first hollow is 0 The antenna according to any one of claims 1 to 6, wherein the antenna is equal to or less than 27λ (λ: wavelength of a frequency used by the antenna). The antenna according to any one of claims 1 to 7, wherein a depth of the one or more grooves is 0.51λ or less. The one or more grooves are a first groove formed in the vicinity of the first hollow slot surface on the substrate surface, and on a side farther from the first hollow than the first groove. The antenna according to claim 1, comprising an adjacent second groove. The substrate has a laminated structure in which a plurality of plates are laminated,
The plurality of plates include a first plate having the substrate surface, and a second plate disposed on the back side of the substrate surface,
The first plate has a first through hole that forms the one or more grooves, and a second through hole that forms the one or more slot elements,
The antenna according to any one of claims 1 to 9, wherein the second plate has a region closing the first through hole. The antenna according to any one of claims 1 to 10, wherein a conductor member is provided in front of the substrate surface and in front of the one or more grooves. A radar equipped with the antenna according to any one of claims 1 to 11.

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