DE112024001226T5 - ANTENNA DEVICE, ANTENNA AND VEHICLE - Google Patents

Abstract

An antenna device comprising a plurality of antennas arranged on a vehicle along a latitude direction intersecting the vehicle's direction of travel, includes: a first antenna supporting radio waves at a first frequency; and a second antenna supporting radio waves at a second frequency band whose fractional bandwidth is smaller than the fractional bandwidth of the first frequency, the second antenna being arranged on an outside relative to the first antenna in the latitude direction of the vehicle, the second antenna.

Description

[Technical field]

The present disclosure relates to an antenna device, an antenna and a vehicle.

[State of the art]

PTL 1 discloses an antenna device comprising multiple antennas housed within an interior of an antenna enclosure.

[Citation list]

[Patent literature]

[PTL 1] Japanese publication of patent application no. 2016-208291

[Summary of the invention]

[Technical problem]

When multiple antennas are housed in a confined space such as an antenna enclosure, as in the antenna device according to PTL 1, the characteristics of the respective antennas can be influenced depending on the arrangement of the multiple antennas.

With regard to such a problem, the present disclosure relates, for example, to the realization of an antenna device that makes it possible to suitably arrange several antennas, an antenna that forms an antenna within the antenna device, and a vehicle on which the antenna device or the antenna is mounted. The present disclosure also relates to further matters that will become apparent from the description contained herein.

[Solution to the problem]

One aspect of the present disclosure is an antenna device with a plurality of antennas arranged on a vehicle along a latitude direction intersecting the direction of travel of the vehicle, wherein the antenna device comprises: a first antenna supporting radio waves at a first frequency; and a second antenna supporting radio waves at a second frequency band whose fractional bandwidth is smaller than the fractional bandwidth of the first frequency, wherein the second antenna is arranged on an outside relative to the first antenna in the latitude direction of the vehicle.

Another aspect of the present disclosure is an antenna comprising: a plurality of antennas contained in an antenna device, wherein the plurality of antennas are arranged on a vehicle along a latitude direction intersecting the direction of travel of the vehicle, wherein the antenna is arranged on an outside in the latitude direction of the vehicle relative to the first antenna supporting radio waves at a first frequency, and wherein the antenna supports radio waves at a second frequency band whose fractional bandwidth is smaller than the fractional bandwidth of the first frequency.

Another aspect of the present disclosure is a vehicle on which a plurality of antennas are mounted, arranged along a latitude direction intersecting the direction of travel of the vehicle, the vehicle comprising: a first antenna supporting radio waves at a first frequency; and a second antenna supporting radio waves at a second frequency band, the fractional bandwidth of which is smaller than the fractional bandwidth of the first frequency, the first antenna and the second antenna being mounted in that order from a center to an outside in the latitude direction of the vehicle.

According to the aspects of the present disclosure described above, it is possible to realize an antenna device in which several antennas are suitably arranged, an antenna that forms an antenna in the antenna device, and a vehicle on which the antenna device or the antenna is mounted.

[Brief description of the drawings]

• 1 Figure 1 is a side view, partly in cross-section, of a vehicle C with which an antenna device 10 is provided according to an embodiment of the present disclosure.
• 2 is a perspective view of the top surface U of a vehicle C.
• 3 is a perspective view of an antenna device 10.
• 4 is a perspective view of the top U of a vehicle C with housings 7, 8 removed.
• 5 is a perspective view of an antenna device 1A with the housing 7 removed.
• 6 This is a side view of an antenna 4.
• 7A This is a top view of antenna devices 1A, 1B.
• 7B This is a front view of antenna devices 1A, 1B. The illustration of one antenna 6 has been omitted.
• 8 This is a side view of an antenna 5.
• 9A is a diagram illustrating a relationship between a resonant frequency and a distance between elements in an antenna 3.
• 9B is a diagram that illustrates a relationship between a resonant frequency and a distance between elements in an antenna 2.
• 10A is a diagram illustrating a relationship between return loss and the distance between elements in an antenna 3.
• 10B is a diagram illustrating a relationship between return loss and the distance between elements in an antenna 2.
• 11 is a table showing the sensitivity of an antenna 4 when the antenna(s) 2, 3 are adjacent and when an antenna 4 is used alone.
• 12A The result of a calculation shows how the gain (dBi) in a horizontal plane of an antenna 5 changes in all directions when the antenna 5 is arranged in the middle in a latitude direction.
• 12B The result of a calculation shows how the gain (dBi) in a horizontal plane of an antenna 5 changes in all directions when the antenna 5 is positioned off-center in a latitude direction.
• 13A is a diagram illustrating a first example of the arrangement of an antenna 5.
• 13B is a diagram illustrating a second example of the arrangement of an antenna 5.
• 13C is a diagram illustrating a third example of the arrangement of an antenna 5.
• 14A This is a diagram of a first example illustrating a relationship between a roof panel C1 and antennas.
• 14B is a diagram of a second example illustrating a relationship between a roof panel C1 and antennas.
• 15A is a diagram showing a first example of the arrangement of diversity antennas arranged on a recessed section R.
• 15B is a diagram showing a second example of the arrangement of diversity antennas arranged on a recessed section R.

[Description of the embodiments]

At least the following facts will be evident from the description in this document and the accompanying drawings.

With reference to the drawings, preferred embodiments of the present disclosure are described below. The identical or equivalent components, parts, and the like shown in the drawings are identified by the same reference numerals, and any redundant description thereof is omitted where appropriate.

In the following description, "essentially quadrilateral" or "rectangular" refers to a shape with four sides, such as a square and a rectangle, and where, for example, at least some of the corners may be cut off at an angle to the side(s), or at least some of the corners may have a curve. Furthermore, an "essentially quadrilateral" or "rectangular" shape may be such that some of the sides may have a recess (recessed portion) or a projection (protruding portion).

= = First embodiment ==

<<Overview of antenna device 10>>

An overview of an antenna device 10 of an embodiment of the present disclosure is given with reference to the 1 and 2 described.

The antenna device 10 comprises antenna devices 1A, 1B (described below), each comprising multiple antennas, and is a vehicle-mounted antenna device intended for use in a vehicle C, which is a wheeled vehicle. Here, the antenna device 10 is not limited to an aspect in which it is mounted on the vehicle C, but can also include an aspect in which it is installed in and used within the vehicle C. In one embodiment of the present disclosure, for example, the antenna device 10 is mounted on a recessed section R located below a top surface U (including a roof, loop panel, and tailgate) of the vehicle C and above a ceiling surface in the vehicle interior. The antenna device 10 However, it can be located in a different place than the recessed section R, for example on a spoiler, a roof control panel, or the like. Furthermore, the antenna device 10 can be an antenna device for something other than a vehicle. For example, the antenna device 10 can be used for a flying object such as a drone or the like, as well as for a mobile vehicle such as a probe, wheelless construction equipment, agricultural machinery, a ship, or the like. Furthermore, the antenna device 100 can be an antenna device used for something other than the mobile body.

The upper part of the recessed section R is covered with a resin roof panel C1, which forms part of the top surface U (see 8 below).

The size of the recessed section R, in which the antenna device 10 is to be accommodated, is limited. Therefore, it is necessary to miniaturize the device, which forms an antenna group comprising antennas 2, 3, 4, 5 and 6, while maintaining the sensitivity of the respective antenna 6, antenna 5 and antennas 2, 3 and 4, as described below.

In the following description, directions are defined in relation to the direction as seen from a driver's seat S of vehicle C, as shown in 1 As illustrated, a direction directed forward from the driver's seat S of vehicle C is defined as "front," and an opposite direction (the direction backward from the driver's seat S) as "rear." Furthermore, a direction directed to the left from the driver's seat S of vehicle C, which is also a direction perpendicular to the forward-backward direction, is "left," and an opposite direction (direction directed to the right from the driver's seat S) is "right." A left-right direction is also a width direction of vehicle C. Furthermore, an upward direction from the driver's seat S of vehicle C, which is also a direction perpendicular to the forward-backward direction and the left-right direction, is "up," and an opposite direction (direction directed downward from the driver's seat S) is "down." The direction definitions described above and the like are also valid for other embodiments in this description, unless otherwise specified.

The antenna device 10 comprises the antenna device 1A and the antenna device 1B (see e.g. 2 ).

The antenna device 1A comprises a substantially cuboid housing 7 that covers the antenna 2, the antenna 3 and the antenna 4, and covers the antennas 2, 3 and 4 from above, as shown in the 2 , 3 , 4 , 5 , 6 , 7 until 8 The antenna assembly 1A additionally includes the ground section 9, which acts as the ground for antennas 2, 3, and 4, on its underside relative to antennas 2, 3, and 4. The antenna assembly 1A is located in the recessed section R on the right side relative to a diversity antenna E and a diversity antenna D. The diversity antennas E and D can be another antenna or an electronic device such as a communication module, a receiver, a camera unit, or the like.

The antenna device 1B is, as shown in the 2 , 3 , 4 , 5 , 6 , 7 until 8 The antenna assembly 1A is shown on the left side relative to the antenna assembly 1A. The antenna assembly 1B comprises a housing 8 that covers the antennas 5 and 6, and covers the antennas 5 and 6 from above. The antenna 5 is located on a centerline CL of the vehicle C in the latitude direction. First, each of the antennas 2, 3, and 4 contained in the antenna assembly 1A is described.

(Antenna 2)

Antenna 2 is, as in the 3 , 4 , 5 , 6 , 7A and 7B The antennas are shown, positioned on the far left and closest to the center line CL, below antennas 2, 3, and 4. Antenna 2 is an antenna capable of receiving digital audio broadcasting (hereinafter referred to as "DAB") and corresponds to the frequency band from 174 MHz to 240 MHz (hereinafter referred to as the "DAB frequency band"). For example, antenna 2 may be an antenna that supports radio waves in frequency bands used for GSM, UMTS, LTE, telematics, Wi-Fi, Bluetooth, and/or the like. Furthermore, antenna 2 may support a portion of the radio waves in a frequency band (for example, only for 5G) below those used for those frequency bands. Note that Wi-Fi and Bluetooth are registered trademarks.

Antenna 2 is described in detail below.

(Antenna 3)

Antenna 3 is an FM antenna, which, as described in the 3 , 4 , 5 , 6 , 7A and 7B As shown, antenna 3 is positioned on the right side relative to antenna 2, with a distance between them. Antenna 3 supports a frequency band with a fractional frequency. bandwidth which is smaller than that of antenna 2, and in one embodiment of the present disclosure supports the frequency band from 88 MHz to 108 MHz, which is the frequency band of a frequency modulation (FM) radio broadcast (hereinafter optionally referred to as the ‘FM frequency band’), so that it can receive it.

It should be noted that antenna 3 can be an antenna that supports radio waves in frequency bands used in GSM, UMTS, LTE, telematics, Wi-Fi, Bluetooth, and/or similar technologies. Furthermore, antenna 3 can support a portion of the radio waves in a specific frequency band (for example, only for 5G) among those in other frequency bands. Even if any frequency band is to be supported, the fractional bandwidth of antenna 3 is configured to be smaller than the fractional bandwidth of antenna 2.

Antenna 3 is described in detail below.

(Antenna 4)

Antenna 4 is, as in the 3 , 4 , 5 , 6 , 7A and 7B As shown, the antenna 4 is positioned on the right side relative to antenna 3 with a distance between them. Antenna 4 is an antenna that receives medium-wave radio broadcasts and, in one embodiment of the present disclosure, supports the frequency range from 530 kHz to 1710 kHz of an amplitude modulation (AM) broadcast (hereinafter optionally referred to as the "AM frequency band"), so that it can be received.

The antenna 4 is an AM antenna based on an inverted-L type and comprises a substrate 41, a support section 42, a coil 43 and an element 45 which is supported by the support section 42 such that it is essentially parallel to the ground section 9 (see 5 and 6 ).

The substrate 41 is essentially a rectangular substrate provided on the top side of the ground section 9 and electrically connected to the ground section 9. An electronic component (not shown), such as an amplifier that amplifies a signal from the antenna 4, is mounted on the substrate 41.

It should be noted that "connected" also includes "electrically connected," without being limited to a physical connection. Additionally, an electrical connection includes a connection using an electronic circuit, an electronic component, or the like, without being limited to a connection by means of a conductor. The same applies to the following explanation.

The support section 42 is a component that supports the element 45 such that the element 45 is substantially parallel to the ground section 9, and is positioned on the substrate 41 such that it extends upwards over the substrate 41. A coil 43, electrically connected to the substrate 41, is wound around the outer circumference of the support section 42. The coil 43, together with the element 45, supports the radio waves in the AM broadcast frequency band and is connected to both the element 45 and the substrate 41. It should be noted that the support section 42 can be formed by a conductor wire or a printed circuit board and can be connected to both the element 45 and the substrate 41 without the coil 43 being present.

Element 45 is a flat, capacitive charging element made of a conductor such as metal and is essentially rectangular in plan view. Element 45 is located on the upper part of the support section 42 and is electrically connected to the coil 43. The length of element 45 from front to back is essentially 70 mm, and its width from left to right is essentially 40 mm. It should be noted that element 45 can have a shape to suppress interference from other antennas, for example, a meandering or spiral shape, as long as the surface area of element 45 can be used effectively.

The explanation of the structure of the inverted L-antenna of antenna 4 using the 6 is applicable in the same way to antenna 2. That is, antenna 2 is a DAB antenna based on the inverted-L type and comprises a substrate 21, a support section 22, a coil 23 and an element 25 which is supported by the support section 22 such that it is essentially parallel to the ground section 9 (see 5 ).

Substrate 21, like substrate 41 of antenna 4, is an essentially rectangular substrate provided on the top side of ground section 9 and electrically connected to ground section 9. An electronic component (not shown), such as an amplifier that amplifies a signal from antenna 2, is mounted on substrate 21.

The support section 22, like the support section 42 of the antenna 4, is a component that supports the element 25 such that the element 25 is substantially parallel to the ground section 9, and is provided on the substrate 21 such that it extends upwards over the substrate 21. Although in 5 Not shown, coil 23 is wound around the outer circumference of the support section 22 and electrically connected to the substrate 21. Coil 23, together with element 25, amplifies the radio waves in the DAB frequency band and is connected to both element 25 and substrate 21. Note that the support section 22 can be formed by a conductor wire or a printed circuit board and can be connected to element 25 and substrate 21 without omitting coil 23.

Element 25, like element 45 of antenna 4, is a flat, capacitive charging element made of a conductor such as metal and has a rectangular shape in plan view. Element 25 is located on the upper part of the support section 22 and is electrically connected to the coil 23. The length of element 25 from front to back is essentially 70 mm, and its width from left to right is essentially 130 mm. It should be noted that element 25 can have a shape to suppress interference from other antennas, for example, a meandering or spiral shape, as long as the surface area of element 25 can be used effectively.

Furthermore, the structure of the inverted L-antenna of antenna 4 is explained using the 6 applicable in the same way to antenna 3. That is, antenna 3 is the inverted-L-type FM antenna and comprises a substrate 31, a support section 32, a coil 33, and an element 35 which is supported by the support section 32 such that it is essentially parallel to the ground section 9 (see 5 ).

Substrate 31, like substrate 41 of antenna 4, is an essentially rectangular substrate provided on the top side of ground section 9 and electrically connected to ground section 9. An electronic component (not shown), such as an amplifier that amplifies a signal from antenna 3, is mounted on substrate 31.

The support section 32, like the support section 42 of the antenna 4, is a component that supports the element 35 such that the element 35 is substantially parallel to the ground section 9, and is provided on the substrate 31 such that it extends upwards over the substrate 31. Although in 5 Not shown, the coil 33 is wound around the outer circumference of the support section 32 and electrically connected to the substrate 31. The coil 33, together with the element 35, amplifies the radio waves in the FM frequency band and is connected to both the element 35 and the substrate 31. It should be noted that the support section 32 can be formed by a conductor wire or a printed circuit board and connected to both the element 35 and the substrate 31, omitting the coil 33.

Element 35, like element 45 of antenna 4, is a flat-plate capacitive charging element made of a conductor such as metal and is essentially rectangular in plan view. Element 35 is located on the upper part of the support section 32 and is electrically connected to the coil 33. The length of element 35 from front to back is essentially 70 mm, and its width from left to right is essentially 100 mm. It should be noted that element 35 can have a shape to suppress interference from other antennas, for example, a meandering or spiral shape, as long as the surface area of element 35 can be used effectively.

At least two of the substrates 21 of antenna 2, substrates 31 of antenna 3 and substrates 41 of antenna 4 described above can be integrated as the same component.

The following is an explanation of antennas 5 and 6, which are contained in antenna device 1B, which is provided on the left side relative to antenna device 1A.

(Antenna 5)

Antenna 5 supports radio waves in a frequency band used, for example, in Vehicle to Everything (V2X: vehicle-to-vehicle communication, road-to-vehicle communication), so that it can send and receive them.

Antenna 5 is an antenna contained within antenna device 1B and is arranged on the left side relative to antenna device 1A, as shown in the 2 , 4 , 7A and 7B The antenna 5 is shown and is essentially located in the middle in the lateral direction with respect to the vehicle C. The antenna 5 comprises a grounding section 51, an element 52, a reflector 53, and a flat, substantially rectangular substrate 54 (see figure). 8 ).

The grounding section 51 is a substantially cuboid component formed from a conductor such as metal and is electrically connected to the vehicle C. It should be noted that the grounding section 51 can be integrally formed with the vehicle C or it can be a separate component from the vehicle C. In one embodiment of the present disclosure, the height of the grounding section 51 is defined by the base surface of the The deepened section R is determined such that the properties of antennas 5, 6 are desirable.

Element 52 is a rod-shaped conductor that serves as a vertically polarized monopole antenna used in V2X communication and extends upwards from substrate 54. Element 52 is positioned essentially in the center in the latitude direction of vehicle C.

It should be noted that the length of element 52, which extends upwards, can increase further, so that the roof panel C1 arches upwards, so that element 52 lies below the roof panel C1 of vehicle C.

The reflector 53 is a rod-shaped conductor located near the element 52 and is positioned so that it extends upwards from the substrate 54. The reflector 53 is a parasitic element that acts as a reflector and serves to improve the gain of the antenna 5 in the forward direction of the vehicle C.

(Antenna 6)

Antenna 6 is a patch antenna located to the left of antenna 5. Antenna 6 is used in the Global Navigation Satellite System (GNSS) and supports the GNSS frequency band, enabling it to receive signals. Examples of GNSS frequency bands include the L1 band (center frequency: 1575.42 MHz), the L2 band (center frequency: 1227.60 MHz), and the L5 band (center frequency: 1176.45 MHz).

Antenna 6 is, as in 7A The antenna 6 is shown to be provided on the ground section 51 and comprises a flat-plate dielectric 61, which is arranged on the left side relative to the antenna 5, and a radiating element 62, which is provided on the upper part of the dielectric 61. The antenna 6 functions as a patch antenna and is arranged on the top side of the ground section 51.

It should be noted that the mass section 51 can be integrally formed as described above, or it can be divided into two or more parts, and the antenna 5 and the antenna 6 are separately grounded.

The dielectric 61 consists of a dielectric material such as ceramic or the like. The radiating element 62 supports the radio waves in the L1, L2, and L5 bands. It should be noted that the configuration is not limited to this; various patch antenna configurations can be used, such as a layered patch antenna, a patch antenna that resonates with the radio waves of several frequency bands, a patch antenna formed from sheet metal without the use of a dielectric material, a patch antenna that combines the above, and the like. Furthermore, a parasitic element that adjusts the directivity in the direction of the elevation angle can be arranged on the top surface relative to or around these patch antennas.

(Mass section 9)

As in the 3 , 5 and 6 As shown, the ground section 9 is designed as an essentially rectangular component in the up-down direction. The ground section 9 is electrically and mechanically connected to the vehicle C by means of a fastener such as a screw and functions as the ground for antennas 2, 3, and 4, which are contained in the antenna assembly 1A. Alternatively, however, the ground section 9 can function as the ground for only some of the antennas 2, 3, and 4. For example, ground section 9 can function as the ground for antenna 2, and another ground section can function as the ground for antennas 3 and 4. The method for joining the ground section 9 to the vehicle C can include, in addition to the use of the fastener, other methods such as welding, gluing, or the like.

In one embodiment of the present disclosure, the mass section 9 is designed as an integral metal plate (sheet), as shown in 5 The ground section 9 can, however, be formed from a plurality of separate metal plates. For example, the ground section 9 can have a configuration in which one metal plate equipped with antennas 2, 3 and another metal plate equipped with antenna 4 are electrically connected.

It should be noted that the ground plane 9 may be formed from a component other than a plate-shaped component, as long as the ground plane 9 functions as the ground of the antenna contained in the antenna device 1A. Furthermore, the ground plane 9 may comprise any combination of a metal component and a component made of a material other than metal, as long as the ground plane 9 functions as the ground of the antenna contained in the antenna device 1A. For example, the ground plane 9 may comprise a metal plate and a resin insulator. The ground plane 9 may also be formed by a single substrate in which a conductive pattern is formed on a printed circuit board (PCB).

(Distance between antennas 2 and 3)

Elements 25 and 35 are arranged with a predetermined distance between them, as shown in the 7A and 7B This distance is preferably set to 20 mm for the following reasons.

The 9A and 9B These diagrams illustrate the relationship between the distance between elements 25 and 35 and the resonant frequencies of antennas 2 and 3. It is evident that if the distance between elements 25 and 35 is 20 mm or less, both resonant frequencies of elements 2 and 3 change significantly, and the designed performance cannot be achieved.

The 10A and 10B These are diagrams illustrating the relationship between the distance between elements 25 and 35 (distance between their facing sides) and the return loss of antennas 2 and 3. It is evident that when the distance between elements 25 and 35 is 20 mm or less, the return loss of element 3 in particular fluctuates considerably, and the designed performance cannot be achieved.

If the distance between elements 25 and 35 is set to more than 20 mm, it is possible to prevent a deterioration in the performance of antennas 2 and 3; however, this inevitably leads to an increase in the size of the antenna device 1A. Considering both the greatest possible miniaturization of the antenna device 1A and the maintenance of the performance of antennas 2 and 3, it is preferable to set the distance between elements 25 and 35, i.e., between antennas 2 and 3, to 20 mm.

(Distance between antennas 3, 4)

11 illustrates the effect of the arrangement of antennas 2, 3 on the sensitivity of antenna 4. 11 Figure 4 shows the results of the sensitivity measurement of antenna 4 in each of the following cases: when antenna 4 is used alone (No. 1); when antenna 2 is adjacent (No. 2); when antenna 3 is adjacent (No. 3); and when antennas 2 and 3 are each adjacent on two sides (No. 4). The distance between the antennas, i.e., between the elements, is assumed to be 20 mm.

As in 11 As shown, when antennas 2 and 3 are adjacent (No. 4), the reduction in sensitivity compared to the case where antenna 4 is used alone (No. 1) is limited to approximately 2 dB. When either antenna 2 or 3 is arranged so that it is adjacent (Nos. 2 and 3), the reduction in sensitivity of antenna 4 is limited to approximately 1 dB.

Thus, it is possible to implement the antenna device 1A in a small size for an antenna 4 that supports AM broadcasting, without causing a significant reduction in its performance, if the antenna 4 is arranged at a distance of 20 mm from the antennas 2, 3.

Taking the arrangement order into account, sufficient performance can also be achieved if antennas 2 and 3 are each arranged on two sides of the antenna. However, it is preferable to arrange either antenna 2 or 3 so that it is adjacent to antenna 4, as shown in the 5 , 7A and 7B depicted.

(Arrangement variants of antennas 2, 3 and 4)

Considering the various arrangement options for antennas 2, 3, and 4, it is preferable to place antenna 4 at one end (either right or left) below the three antennas, rather than in the center as described above. Considering the arrangement of antennas 2 and 3, it is desirable to place antenna 3, with a fractional bandwidth smaller than that of antenna 2, in the center. This is because the influence of the adjacent antenna on the resonant frequency increases with increasing fractional bandwidth. Furthermore, the overall system load is lower when the frequency characteristic of antenna 3, which has a smaller fractional bandwidth, is selected, compared to when the frequency characteristic of antenna 2 is selected. In this respect, the fractional bandwidth of antenna 3 is 20% (frequency: 88 MHz to 108 MHz), and the fractional bandwidth of antenna 2 is 32% (frequency: 174 MHz to 240 MHz).

As a result of the foregoing considerations, as stated in the 5 , 7A and 7B As shown, antennas 2 and 4 are arranged at the ends of antenna device 1A, and antenna 3 is arranged in the middle. With such an arrangement, antenna device 1A exhibits good performance in each of the corresponding frequency bands of antennas 2, 3, and 4.

(Location of antenna 5)

The antenna 5, which is a communication antenna used in V2X, should preferably be mounted substantially in the center in the latitude direction of the vehicle C, as described below.

Considering vehicle-to-vehicle communication, it is desirable for antenna 5 to have a directivity pattern in both the forward and reverse directions. It should be noted that antenna 5 can be configured with two antennas, which maintain the gain in the forward and reverse directions of the vehicle C, thus achieving a diversity effect. If antenna 5 is not located substantially in the center in the latitude direction of the vehicle C (for example, if it is located at the end in the latitude direction of the vehicle C), a tilt in the directivity pattern in the forward and reverse directions of the vehicle C occurs, leading to a reduction in gain or the occurrence of zero signals in a required coverage area. 12B Figure 1 illustrates the directional effect in the forward direction of vehicle C). It should be noted that by changing the arrangement from the end section in the lateral direction of vehicle C to essentially the middle in the lateral direction, the inclination in the directional effect is suppressed, thereby achieving a symmetrical waveform.

In contrast, if element 52 of the antenna 5 is arranged essentially in the middle in the lateral direction of the vehicle C, the inclination in the directivity in the forward-backward direction is eliminated, and thus the antenna 5 can have a directivity that is almost symmetrical in the left-right direction ( 12A : illustrates the directional effect in the forward direction of vehicle C).

Furthermore, considering the improvement of the sensitivity of the antenna 5, it is desirable that the element 52 be mounted in the highest possible position. Therefore, the base of the element 52 is attached to the top of the ground section 51 (see 8 ).

<Further embodiment of the arrangement of antenna 5>

In 7B The element 52 of the antenna 5 is positioned on the ground section 51 such that it lies at a higher position relative to the bottom surface of the recessed section R; however, this is not limited to this. For example, as in 13A As shown, element 52 is arranged on a projection 100 that extends upwards from the bottom surface of the recessed section R. It should be noted that the projection 100 is a section formed by machining part of the recessed section R of the vehicle C and acts as a mass. In the 13A , 13B and 13C For the sake of clarity, the roof panel C1 has been omitted.

For example, in 13B An insulating spacer 110 and a metallic plate-shaped mass section 120 are provided, wherein the insulating spacer 110 is provided on the bottom surface of the recessed section R and the mass section 120 is held by the spacer 110. In such a case, the element 52 can be arranged on the mass section 120.

Furthermore, it is assumed that element 52 is an element serving as a vertically polarized monopole antenna used in V2X communication, but this is not the only possible application. For example, instead of monopole element 52, element 130 can be used, serving as a vertically polarized dipole antenna used for V2X communication. If such element 130 is used, it simply needs to be placed on an insulating spacer 140, which is positioned at the recessed section R, as shown in 13C depicted.

As in the 7B , 13A , 13B and 13C As shown, if elements 52 and 130 can be placed at a higher position relative to the bottom surface of the recessed section R, they will be less affected by other antennas. Accordingly, it is possible to prevent the reduction in gain and the deterioration in the directivity of elements 52 and 130 (i.e., antenna 5 for V2X).

In one embodiment of the present disclosure, it is assumed that elements 52 and 130 support V2X communication, but they can also be used in other communication standards with frequencies higher than the DAB and FM frequency bands. If the element (the antenna) supporting the frequency band higher than the DAB frequency band is placed in a higher position, the same effect as in one embodiment of the present disclosure can be achieved.

<Ratio between roof panel C1 and antenna>

For example, as in 14A As shown, the shape (here the height) of the mass section 51 is adjusted so that the upper end of the element 52 is higher than the antenna 2. Even in such a case, as shown in 7B Antenna 5 exhibits good properties at a high position. Here, it is assumed that the height of element 52 from the bottom surface of the recessed section R is greater than the height of antenna 2; however, these two could be the same height. Furthermore, the height of element 52 from the bottom surface of the recessed section R could be less than the height of antenna 2.

As in the 7B , 14A and 14B As shown, the roof panel C1 has an arc shape. Thus, the distance between the underside of the roof panel C1 and the floor surface of the recessed section R is greatest near the center of the vehicle C and gradually decreases from the center of the vehicle C towards the left and right.

Here's the thing: Even if antenna 4 for the AM frequency band has a low height, it's possible to ensure sufficient gain by increasing its length in the left-right direction. Accordingly, antenna 4 for the AM frequency band is positioned at the rear of vehicle C in the left-right direction (here, at the right rear).

Furthermore, the fractional bandwidth of antenna 3, which supports radio waves in the FM frequency band, is smaller than the fractional bandwidth of antenna 2, which supports radio waves in the DAB frequency band. In this case, it is difficult for an antenna with a large fractional bandwidth to maintain the gain across the entire frequency band unless the antenna height is increased. Accordingly, in one embodiment of the present disclosure, antenna 2 with a larger fractional bandwidth is provided on the central side of the vehicle C relative to antenna 3.

Furthermore, in one embodiment of the present disclosure, for example, as in 14A As shown, the heights of antennas 2, 3, and 4 gradually decrease from the center of vehicle C to the right end of vehicle C. By varying the heights of antennas 2, 3, and 4 in this way, the gains of the antennas at the respective positions can be increased. In one embodiment of the present disclosure, it is assumed that antennas 2, 3, and 4 have different heights, although they can also be the same height.

Furthermore, in one embodiment of the present disclosure, element 35 of antenna 3 and element 45 of antenna 4 are supported such that they are substantially parallel to the ground section 9; however, this is not limited to this. For example, as in 14B As shown, elements 35 and 45 are supported in such a way that they are positioned higher on the central side of the vehicle C. Even in such a case, it is possible to achieve a similar effect to that in an embodiment of the present disclosure.

< Arrangement of the diversity antenna in the recessed section R >

In one embodiment of the present disclosure, for example, in 7B The representation of antennas D and E has been omitted; however, as shown in 15A As shown, in addition to antennas 2, 3, and 4, antennas D and E are arranged in the recessed section R. For example, antennas D and E can form a diversity antenna on the left and right sides of the vehicle, so that antennas identical to antennas 2 and 3 are arranged to achieve a diversity effect with antennas 2 and 3. That is, in the 15A In the antenna device 10 shown, antennas 2 and 3 are arranged on the right side relative to antenna 5, and antennas D and E are arranged on the left side relative to antenna 5. Furthermore, a communication antenna for Wi-Fi or the like can also be newly mounted in the antenna device 10.

The arrangement of antennas 2, 3 and 4, as well as the diversity antennas D and E, is not limited to this. For example, the arrangement in 15B The arrangement shown is used. That is, in the arrangement shown in 15B In the antenna device 10 shown, antennas D and 3 are arranged on the right side relative to antenna 5, and antennas E and 2 are arranged on the left side relative to antenna 5. Furthermore, if antennas 2, 3, D, and E are communication antennas, they can be used as MIMO antennas.

The foregoing describes embodiments and modifications of the present disclosure with reference to the drawings; however, they are merely examples of the present disclosure, and various configurations may also be assumed that differ from those described above.

< Effect >

In one embodiment of the present disclosure, the antenna device 10 comprises a plurality of antennas 2, 3 (corresponding to a "first antenna" and a "second antenna," respectively) arranged on the vehicle C along the latitude that intersects the direction of travel of the vehicle C. Antenna 2 supports the radio waves in the DAB frequency band (corresponding to a "first frequency band"). Antenna 3 supports the FM frequency band (corresponding to a "second frequency band") with a fractional bandwidth that is smaller than that of the DAB frequency band.

With such a configuration, the antenna device 10 is able to suppress the influence on the resonant frequency, can also be placed in a confined space, and exhibits high performance. This makes it possible to appropriately utilize the plurality of antennas 2, 3 in an embodiment of the present disclosure. to arrange them. Furthermore, it is possible to suppress the load on the amplifiers of antennas 2 and 3. By providing antennas 2 and 3, the antenna device 10 is able to support a wide bandwidth.

The vehicle C comprises the top surface U and the recessed section R, which extends downwards from the top surface U, and the antenna device 10 is arranged on the recessed section R.

With such a configuration it is possible to mount the antenna device 10 on the vehicle C, suppressing the influence on the shape and interior of the vehicle C.

The antenna device 10 supports the radio waves in the frequency band of medium wave broadcasting and further includes the antenna 4, which is arranged on the outside in the latitude direction relative to the antenna 3.

With such a configuration, antennas 2, 3, and 4 can collectively suppress the influence on the resonant frequency and exhibit high performance. Furthermore, it is possible to miniaturize the entire antenna system 10. It is also possible to reduce the load on the amplifiers of antennas 2, 3, and 4.

Antennas 2, 3, and 4 are spaced apart to prevent interference between them. This means it is possible to suppress the influence on the resonant frequency.

At least one of the antennas 2, 3 and 4 includes the flat-plate-shaped element 25, 35, 45. By realizing a capacitively charged antenna with such an element 25, 35, 45, the antennas 2, 3 and 4 can reduce the height of the antenna and achieve a miniaturized device.

The antenna device 10 further comprises a housing 7 which is designed to accommodate the antennas 2, 3 and 4, thereby facilitating assembly and transport in relation to the vehicle C.

The antenna device 10 further comprises the antenna 5 (corresponding to a “vehicle communication antenna”), which is mounted on the vehicle C, wherein the antenna 5 is arranged relative to the first antenna on the central side in the latitude direction and is capable of communicating with a vehicle other than the vehicle C.

If the antenna 5 is positioned near the center of the vehicle C, the antenna 5 can achieve good directivity, as shown in the 12A , 12B and the like.

The antenna 5 is arranged on the ground section 51 (corresponding to a "second ground section"), which is positioned above the ground section 9 (corresponding to a "first ground section"), on which the antenna 2 and the antenna 3 are arranged.

By mounting the antenna in a high position, antenna 5 can exhibit high sensitivity.

The antenna device 10 further comprises the antenna 6 (corresponding to a “satellite communication antenna”), which is mounted on the vehicle C, is arranged on the ground section 51 and is equipped to communicate with a satellite.

In one embodiment of the present disclosure, antenna 2 is the DAB antenna, and antenna 3 is the FM antenna. Antennas 2 and 3 exhibit good reception sensitivity.

[List of reference symbols]

1A, 1B, 10, 500

antenna device

2-6

antenna

7, 8

Housing

9, 51

Mass section

25, 35, 45, 52, 130

element

C

vehicle

R

in-depth section

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions.

Cited patent literature

• JP 2016-208291 [0003]

Claims (12)

An antenna device comprising a plurality of antennas arranged on a vehicle along a latitude direction intersecting the vehicle's direction of travel, the antenna device comprising: a first antenna supporting radio waves at a first frequency; and a second antenna supporting radio waves at a second frequency band whose fractional bandwidth is smaller than the fractional bandwidth of the first frequency, wherein the second antenna is arranged on an outside relative to the first antenna in the latitude direction of the vehicle. The antenna device according to Claim 1 , wherein the vehicle comprises a top and a recessed section which is recessed downwards from the top, and the antenna device is arranged on the recessed section. The antenna device according to Claim 1 or 2 , further comprising: an amplitude modulation (AM) antenna supporting radio waves in a frequency band of a medium wave broadcast, wherein the AM antenna is arranged on an outside in the latitude direction relative to the second antenna. The antenna device according to Claim 3 , wherein the first antenna, the second antenna and the AM antenna are arranged at intervals to prevent interference between the antennas. The antenna device according to Claim 3 or 4 , wherein at least one of the first antenna, the second antenna and the AM antenna comprises a flat plate-shaped element. The antenna device according to one of the Claims 3 until 5 , furthermore comprising: a housing designed to accommodate the first antenna, the second antenna and the AM antenna. The antenna device according to one of the Claims 1 until 6 , further comprising: a vehicle communication antenna mounted on the vehicle, wherein the vehicle communication antenna is arranged relative to the first antenna on a central side in the latitude direction and is capable of communicating with a vehicle other than the vehicle. The antenna device according to Claim 7 , wherein the vehicle communication antenna is arranged on a second ground section, the second ground section being positioned above the first ground section on which the first antenna and the second antenna are arranged. The antenna device according to Claim 8 , further comprising: a satellite communication antenna mounted on the vehicle, wherein the satellite communication antenna is arranged on the second ground section and is equipped to communicate with a satellite. The antenna device according to one of the Claims 1 until 9 , where the first antenna is a digital audio broadcasting (DAB) antenna and the second antenna is a frequency modulation (FM) antenna. An antenna comprising: one of a plurality of antennas contained in an antenna device, wherein the plurality of antennas is arranged on a vehicle along a latitude direction intersecting the direction of travel of the vehicle, in that the antenna is arranged on an outside in the latitude direction of the vehicle relative to the first antenna supporting radio waves at a first frequency, wherein the antenna supports radio waves at a second frequency band whose fractional bandwidth is smaller than the fractional bandwidth of the first frequency. A vehicle on which a plurality of antennas are mounted, arranged along a latitude direction intersecting the vehicle's direction of travel, the vehicle comprising: a first antenna supporting radio waves at a first frequency; and a second antenna supporting radio waves at a second frequency band whose fractional bandwidth is smaller than the fractional bandwidth of the first frequency, the first antenna and the second antenna being mounted in that order from a center to an outside in the latitude direction of the vehicle.