JP2000114857A - Antenna having resin dielectric and method of manufacturing the same - Google Patents

Abstract

[PROBLEMS] To increase the productivity of a microstrip antenna having a resin dielectric. SOLUTION: A patch electrode 14 of a metal plate is attached to a dielectric 10 made of resin. The positioning boss 40 engages with the positioning hole 50 of the patch electrode 14, and the patch electrode 14
Is positioned. The hole shape is set such that the impedance value of the edge of the positioning hole 50 is equal to or less than the impedance value of the antenna circuit. Since positioning is performed at the center of the electrode, there is no adverse effect due to large thermal deformation of the positioning structure. The optimum feeding point can be obtained by considering the impedance. Preferably, the impedance value of the edge of the positioning hole 50 is made equal to the antenna circuit impedance value. Then, the metal plate of the electrode is bent at the edge to form a power supply line.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an antenna having a resin dielectric, and more particularly to an improvement in antenna productivity. The principle of the microstrip antenna is applied to the antenna of the present invention.

[0002]

2. Description of the Related Art As is well known, a vehicular navigation apparatus receives a radio wave from a GPS (Global Positioning System) satellite and calculates a current position using the received radio wave. A microstrip antenna is one of antennas suitable for receiving radio waves from GPS satellites.

A microstrip antenna is a dielectric,
It has a radiation electrode provided on one surface of the dielectric and a ground electrode provided on the other surface. Generally, electrodes are printed and fired on both sides of a ceramic plate material that is a dielectric. Alternatively, a printed circuit board on which a copper pattern is formed by an etching process forms an antenna. Therefore, the conventional antenna has a planar structure.

For example, JP-A-9-64636 discloses that
A ceramic type antenna is disclosed. A concave portion is provided on the bottom surface of the ceramic dielectric, and the circuit element is accommodated in the concave portion. This increases the thickness of the dielectric while maintaining the overall height of the antenna.

The dielectric can be made of general-purpose resin (PBT or the like) instead of ceramic or the like. Conductive plates as radiation electrodes and ground electrodes are adhered to both sides of the dielectric. Although this type of antenna does not have a thin-film electrode, it is in principle the same as a microstrip antenna and can be considered as one of the microstrip antennas.

When a general-purpose resin is used, the size of the antenna tends to be relatively large because the dielectric constant of the resin material is low. However, a dielectric having an arbitrary shape can be formed by resin molding. Particularly, there is an advantage that a dielectric having a three-dimensional and complicated shape can be easily formed and productivity can be greatly improved.

[0007]

A patch-shaped radiation electrode (hereinafter referred to as a patch electrode) made of a conductor plate of aluminum or the like is attached to a resin dielectric. At this time, it is important to accurately position the patch electrode and the dielectric. Displacement or rotation of the patch electrode due to manufacturing variation (displacement in the rotational direction on a plane) affects the antenna characteristics, and can also lead to quality degradation.

In order to perform positioning accurately, it is considered effective to devise the shape of the dielectric. Typically, it is conceivable that a recess having the same shape as the outer shape of the patch electrode is provided in the dielectric, and the patch electrode is fitted into the recess. However, since there is a large difference in the amount of thermal deformation between the metal electrode plate and the resin dielectric due to the difference in the coefficient of thermal expansion, cracks in the dielectric or bending / floating of the electrode plate occur, which may affect antenna performance. . It is desired that the electrodes can be positioned without such an adverse effect.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide an antenna capable of suitably positioning a patch electrode with respect to a resin dielectric and improving the productivity. It is in.

[0010]

According to the microstrip antenna of the present invention, the resin dielectric has a positioning boss, the patch electrode has a positioning hole, and the positioning boss engages with the positioning hole. A patch electrode is positioned. The positioning hole of the electrode is provided such that “the impedance value of the edge is equal to or less than the impedance value of the antenna circuit”. This means that a relatively small hole is drilled in the center of the electrode. Therefore, since the difference in the amount of thermal deformation between the positioning hole and the positioning boss is small, deformation of the dielectric and the patch electrode due to the thermal deformation can be suppressed. Further, since the impedance value of the edge of the positioning hole is equal to or less than the impedance value of the antenna circuit, the feeding point is set at an appropriate location on the electrode, and sufficiently satisfactory antenna performance can be obtained.

As described above, according to the present invention, the patch electrode can be positioned with respect to the dielectric without adversely affecting the thermal deformation and satisfying the antenna performance.

Preferably, an electrode protection cover for covering the patch electrode is provided with a gap between the electrode protection cover and the patch electrode. The positioning boss penetrates through the patch electrode and protrudes from the electrode surface, and supports the electrode protection cover. Since the bending deformation of the electrode protection cover is suppressed by the positioning boss, an appropriate gap between the cover and the electrode can be secured. For example, even if the protective cover is pressed down in the assembling step, improper cover deformation does not occur, so that assembling becomes easier. Therefore, according to the present invention, not only the electrode positioning function but also the cover deformation preventing function is provided with a simple structure in which a boss having an appropriate height is provided, and as a result, antenna productivity can be further improved. It becomes possible.

[0013] Preferably, the positioning hole is provided so that the impedance value of at least a part of the edge of the positioning hole is equal to the impedance value of the antenna circuit. A portion corresponding to the positioning hole of the plate is bent to form an antenna feed line. That is,
According to the present invention, the impedance value of at least a part (or the whole edge) of the edge of the positioning hole is made equal to that of the antenna circuit, and such a part is used as a feeding point.
Then, paying attention to the fact that a portion corresponding to the positioning hole of the electrode plate material is originally unnecessary, and by bending this portion, a power supply line integrally and continuously connected to the electrode portion is formed.

Therefore, according to the present invention, (i) the number of components is reduced, (ii) assembly is easy, and (iii) And (iv) high vibration resistance and heat resistance at the power supply point are obtained. As a result, it is possible to reduce costs and significantly improve productivity and reliability.

Preferably, a ground electrode is attached to the opposite side of the dielectric from the patch electrode, and the ground electrode is located at a position opposed to the outer peripheral edge of the patch electrode with the dielectric interposed therebetween, perpendicular to the patch electrode. Having a surface. According to the present invention, the antenna gain at a low elevation angle can be improved. This is presumably because an electric field having a normal line in the low elevation angle direction is generated between the outer peripheral edge of the patch electrode and the ground electrode vertical surface immediately below the patch electrode.

Another aspect of the present invention is a method of manufacturing an antenna by attaching a patch electrode to a resin dielectric, wherein a plurality of types of patch electrodes are prepared, and A patch electrode having a size corresponding to the dielectric constant is selected. For example, when the dielectric constant of the resin is large, a small patch electrode is selected, and when the dielectric constant is small, a large patch electrode is selected. This makes it possible to absorb variations in the dielectric constant of the resin material, suppress variations in antenna characteristics, and improve quality-related productivity. It is more preferable to consider that the dielectric constant of the resin material varies from lot to lot.

Further, according to the present invention, the antenna can be made thinner. Essentially, when the dielectric is made thinner, the resonance frequency becomes narrower, and the demand for the shape accuracy of the patch becomes higher. According to the present invention, such a request can be met by selecting a patch, so that the antenna can be made thinner.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention (hereinafter, embodiments) will be described below with reference to the drawings.
The microstrip antenna of the present embodiment, for example,
It is suitably used for a GPS receiving antenna of a vehicle-mounted navigation device. However, it is needless to say that the present invention is not limited to the GPS antenna and can be applied to other antennas.

FIG. 1 is a perspective view showing the appearance of the antenna, and FIG. 2 is a central sectional view thereof. Substantially rectangular parallelepiped dielectric 1
0 is formed by molding a general-purpose resin material (PBT in this embodiment). The dielectric 10 is basically a square block, and is symmetrical and symmetrical when viewed from above. A rib 12 is provided on the upper surface of the dielectric 10 along the outer periphery. The square area inside the rib 12 is an electrode mounting surface (area). A patch electrode 14 made of a metal conductor plate such as aluminum is attached to the mounting surface. In the present embodiment, the patch electrodes 14 are adhered using an adhesive or an adhesive tape (the adhesive layer is omitted in the drawing, and the same applies to other adhesive portions hereinafter). However, the patch electrode 14 may be attached by another method. For example, the patch electrode 14 may be fixed by pressing with a not-shown attachment pin.

The patch electrode 14 has a square shape, and one side thereof is set to a half wavelength, thereby forming an antenna that resonates at a desired frequency. Patch electrode 14
The distance between two opposing ribs 12 is set to be longer than one side a, and a gap is formed between the outer end of the electrode and the ribs 12. The gap absorbs the difference in the amount of thermal deformation between the dielectric 10 and the patch electrode 14, and prevents cracking of the dielectric 10 and bending / floating of the patch electrode 14.

The height of the dielectric 10 is H,
Is provided with a square amplifier housing concave portion 18, the depth of the concave portion 18 is d, and the substantial thickness of the dielectric 10 is t. The ground electrode 20 is in close contact with the bottom surface 16 and the inner surface of the storage recess 18. The ground electrode 20 is formed by pressing a metal conductor plate such as aluminum, and is bonded to the dielectric 10 using an adhesive or an adhesive tape.

The ground electrode 20 has a shape conforming to the dielectric 10, and has a first parallel portion 20a, a vertical wall portion 20b, and a second parallel portion 20c. The first parallel portion 20a is
It is in close contact with the ceiling surface of the
It faces the patch electrode 14 with 0 interposed. First parallel part 20
“a” has substantially the same square shape as the patch electrode 14. At the outer peripheral edge of the parallel portion 20a, that is, at the portion facing the outer peripheral edge of the patch electrode 14 across the dielectric 10, the ground electrode 20 is bent substantially vertically,
0b is formed. The vertical wall 20b is formed of the dielectric 10
Is vertically bent again at the lower end thereof, and is connected to the second parallel portion 20c. As a whole, the ground electrode 20 is parallel to the patch electrode 14, but has a stepped structure in which a step portion is provided at a position facing the outer peripheral edge of the patch electrode 14.

The second parallel portion 20c is basically made of the dielectric 10
However, the mounting flange 22 protrudes at the center of each side. The ground electrode 20 (entire antenna element) is screwed to the bracket 26 using the mounting hole 24 of the mounting flange 22. The bracket 26 is
It is fixed to an antenna installation object (not shown), for example, a vehicle body.

In the amplifier housing recess 18 of the dielectric 10,
A preamplifier circuit 28 is attached to the ground electrode 20. That is, the preamplifier circuit 28 is
Affixed to the ceiling. The preamplifier circuit 28
It has a circuit board 28a and an amplifier element 28b. The preamplifier circuit 28 and the patch electrode 14 are connected by a power supply pin 30. The power supply pin 30 penetrates through the dielectric 10, and both ends are soldered to the patch electrode 14 and the amplifier circuit 28. The power supply pin 30 is insulated from the ground electrode 20.

Further, a step portion 12a is provided on the inner peripheral side of the rib 12 on the upper surface of the dielectric material 10. This step 12a
The electrode protection cover 32 is adhered to. The electrode protection cover 32 covers the patch electrode 14, and a predetermined gap is provided between the cover 32 and the electrode 14.

In the antenna having the above configuration, the patch electrode 1
It is required that positioning of the dielectric 4 and the dielectric 10 be performed accurately. If the displacement or the rotation displacement (the displacement in the rotation direction on a plane) is large, the antenna characteristics deteriorate.

In order to meet such a demand, as features of the present embodiment, a positioning boss 40 is provided on the dielectric 10, and a positioning hole 50 is provided on the patch electrode 14. The positioning boss 40 has a polygonal shape (square in this embodiment), and protrudes from the center of the upper electrode mounting surface of the dielectric 10. The positioning boss 40 is formed integrally with the dielectric 10.

On the other hand, the positioning hole 50 is
It has a square shape equivalent to 0. In particular, in the present embodiment, the sizes of the positioning hole 50 and the positioning boss 40 are set such that the impedance value of the edge of the positioning hole 50 is equal to or less than the impedance value of the antenna circuit. If the positioning hole 50 is too large and the impedance value of the edge exceeds the impedance value of the antenna circuit, the feeding point cannot be set to the optimum position on the electrode, which causes a decrease in antenna performance. Have been avoided.

Referring to a specific example, FIG. 3 shows a horizontal axis: the length of one side of the positioning hole 50 (cm), and a vertical axis: an impedance value (Ω) of the outer end of the patch and the inner end of the patch (edge of the positioning hole). The relationship is shown. In this example, the length a of one side of the patch electrode is about 50 mm, and the thickness t of the dielectric 10 is
Is about 4 mm, and the material of the dielectric 10 is PBT having a relative dielectric constant of about 3.5. The impedance value of the antenna circuit is 50Ω. Of particular note is the impedance value at the inner end of the patch.

In the example of FIG. 3, the preferred range of the length of one side of the positioning hole is 2 mm or more and 8 mm or less. Above 8 mm, the impedance value at the inner end of the patch exceeds 50Ω. Therefore, it becomes impossible to set an optimum feeding point on the electrode. The optimum feeding point is a point having an impedance value equal to that of the antenna circuit. On the other hand, if the length of one side of the positioning hole is 8 mm or less, an optimum feeding point can be set somewhere on the electrode. However, when the positioning holes are extremely small, it is impossible to suppress the rotation deviation of the patch electrode. Therefore, the positioning hole should be
A size between 8 mm is considered appropriate.

The shapes of the positioning holes and the positioning bosses are not limited to squares, but may be other polygonal shapes (eg, rectangles and triangles). FIG. 4A shows an example of a triangular positioning hole. Also in this case, the impedance value of the edge of the positioning hole needs to be 50Ω or less. Therefore, a positioning hole of an appropriate shape is included in a square having a side of 8 mm and protrudes from a square having a side of 2 mm. However, it is inappropriate for the positioning hole to protrude from a square having a side of 8 mm as shown in FIG.

It is not necessary that the positioning holes and the positioning boss have the same shape. If the positioning function by engagement is ensured, the shapes of the positioning hole and the positioning boss may be different. For example, the positioning holes may be triangular and the positioning boss may be hexagonal. However, the positioning hole or the positioning boss must not be circular. This is because the rotation deviation of the patch electrode cannot be suppressed.

As described above, according to this embodiment, the provision of the positioning holes 50 and the positioning bosses 40 allows the patch electrode 14 to be positioned well with respect to the dielectric 10.

If positioning is performed at the outer peripheral portion of the electrode, a large stress may be generated in the electrode and the dielectric due to the difference in the amount of thermal deformation. However, in the present embodiment, since the positioning components are arranged at the center of the electrode, their dimensions are small, and the amount of deformation with respect to a temperature change is small. Even if the positioning boss expands at a high temperature, no excessive stress is generated in the dielectric or the patch electrode. Therefore, it is possible to prevent a situation in which the antenna performance is deteriorated due to cracking of the dielectric material, bending / floating of the patch electrode, or the like.

Further, as described with reference to FIG. 3, by setting the shape of the positioning hole in consideration of the impedance value, the feeding point can be set to an optimum position. Therefore, it is possible to accurately position the patch electrode and improve the production quality without sufficiently adversely affecting the antenna performance while sufficiently satisfying the antenna performance.

"Support of protective cover by positioning boss"
In the present embodiment, as shown in FIG. 2, the positioning boss 40 penetrates the patch electrode 14 and protrudes from the electrode surface. The height of the top surface 40a of the positioning boss 40 is
The height is equal to the height of the step 12a of the electrode outer peripheral rib 12. Accordingly, the positioning boss 40 is in contact with the lower surface of the electrode protection cover 32. Thus, the positioning boss 40 supports the protective cover 32 from below, prevents the protective cover 32 from bending and deforming, and secures a proper gap between the protective cover 32 and the patch electrode 14.

This configuration is particularly suitable when the protective cover 32 is assembled. Even if the central portion of the protective cover 32 is pressed down during assembly, the protective cover 32 is prevented from being deformed.

In the assembled state, the positioning boss 4
0 and the protective cover 32 may not be in contact with each other and there may be a small gap between the two. The positioning boss 40 is connected to the protective cover 32.
It is sufficient that the protective cover 32 has a height that can prevent excessive flexural deformation, and that the protective cover 32 is securely supported to secure a gap under the cover.

As described above, in the present embodiment, the positioning boss 40 having an appropriate height is provided with a simple structure.
A cover deformation preventing function is provided as well as an electrode positioning function.

"Integration of Patch Electrode and Feeding Line (Feeding Pinless Structure)" Particularly preferably, regarding the shape setting of the positioning hole, at least a part of the edge where the impedance value is equal to the impedance value of the antenna circuit (equi-impedance) Edge). The portion corresponding to the positioning hole of the patch material plate is bent at the equi-impedance edge to form an antenna feed line.

Referring to FIG. 5, the positioning hole 50 is square, and the length of one side is set to 8 mm. Therefore, the impedance value of the edge is 50Ω, which is equal to the impedance value of the antenna circuit. A metal plate is bent at a central portion 54 of one side 52 of the positioning hole 50 to form a power supply line 56. The width of the feed line 56 is w.
Such an electrode with a power supply line can be easily formed by press punching. That is, the positioning hole 50 is punched out of a metal plate such as aluminum while leaving the power supply line 56. Then, the patch electrode 14 of FIG. 5 is formed by bending the portion of the power supply line 56.

Although not shown in the figure, the dielectric 10 has a position facing the power supply line 56, that is, the positioning boss 40.
A through-hole is provided at the root of. When assembling, feeder 56
Is passed through the through hole. Next, the positioning boss 40 is passed through the positioning hole 50, and the patch electrode 14 is positioned. The patch electrode 14 is adhered to the dielectric 10. The power supply line 56 protrudes from below the amplifier circuit 28, and the tip of the power supply line 56 is soldered to the amplifier circuit 28.

It is needless to say that the impedance value of only a part of the edge of the positioning hole may be equal to the impedance value of the antenna circuit. For example, when adopting a rectangular positioning hole, it is preferable to match the impedance value of the short side to the antenna circuit.

According to the configuration of the present embodiment, the power supply line is formed by using a portion corresponding to the positioning hole of the electrode material plate, that is, a portion that is not originally required. Conventional power supply pins are unnecessary, and cost reduction can be achieved by reducing the number of components.

Further, the power supply line and the patch electrode can be assembled at the same time, and the assembly is easy. It is not necessary to perform soldering at two places as in the case of using a power supply pin, and soldering may be performed at one place, thereby improving productivity.

Further, resin melting due to heat generated when the power supply line is soldered to the patch electrode is eliminated, which is also advantageous in this respect.

Further, since the power supply line is not soldered to the patch electrode, the power supply point is resistant to vibration and heat when the antenna is used, which is advantageous in reliability.

Furthermore, since the cross-sectional shape of the power supply line is rectangular, there is obtained an advantage that the patch electrode is less likely to rotate carelessly than the conventional circular power supply pin.

[Improvement of Antenna Gain at Low Elevation Angle] As described above with reference to FIG.
A vertical wall portion 20b perpendicular to the patch electrode 14 is provided at a position facing the outer peripheral edge of the patch electrode 14 with respect to 0.
That is, the ground electrode 20 has a step portion immediately below the outer peripheral edge of the patch electrode 14. Thereby, the antenna gain in the low elevation angle direction can be improved as compared with the conventional microstrip antenna.

Referring to FIG. 6B, in general, the ground electrode is simply a parallel flat plate. An electric field as shown is formed between the outer periphery of the patch electrode and the ground electrode. The elevation angle θ2 of the normal to the electric field is relatively large. On the other hand, in the case of the configuration of the present embodiment, as shown in FIG. 6A, an electric field is formed between the outer peripheral portion of the patch electrode and the vertical surface (outer surface of the vertical wall) of the ground electrode. Further, an antenna electric field is formed between the outer peripheral portion of the patch electrode and the parallel portion where the ground electrode is lowered by one step. As a result, as shown in FIG. 6A, the elevation angle θ1 in the normal direction of the antenna electric field decreases. It is considered that such an electric field improves the gain at a low elevation angle.

FIG. 7 shows the results of measuring the gain of the conventional ceramic type antenna and the antenna of the present invention. The application of the resin material increases the thickness of the dielectric, thereby improving the gain as a whole. However, as a general tendency, when the thickness of the dielectric material is increased, the gain at a high elevation angle increases, but the antenna gain at a low elevation angle decreases.
However, according to the measurement results of FIG. 7, the antenna gain at a low elevation angle (around 10 °) is also improved. From a relative viewpoint, the antenna gain at a low elevation angle is considerably improved.

Improving antenna gain at low elevation angles is particularly advantageous for GPS antennas. GPS satellite radio waves are stronger than when they arrive from the zenith
It is smaller when coming from a low elevation direction. On the other hand, in order to improve the positioning accuracy, it is better to use a radio wave of a satellite existing in a low elevation angle direction. By using an antenna element having a directivity characteristic such that the gain is high at a low elevation angle, the positioning accuracy can be improved, which is advantageous for the entire system in which the antenna device is provided.

[Simplification of Electromagnetic Shield Structure of Built-in Amplifier] Referring to FIG. 8B, in a conventional ceramic type antenna, a preamplifier circuit board having a preamplifier element is provided on the lower surface of a ceramic substrate via a ground. It is attached. Then, the radiation electrode on the upper surface of the ceramic substrate and the preamplifier circuit are connected by a power supply pin. This antenna is fixed to a bracket, and the entire antenna is covered with an antenna cover. The preamplifier requires an electromagnetic shield. This is to eliminate external radio waves and prevent the amplifier from emitting radio waves. In particular, it is necessary to prevent the antenna from receiving radio waves emitted by the amplifier. Conventionally, as shown in the figure, it is necessary to provide a shield case made of a conductor in order to achieve the electromagnetic shielding of the preamplifier.

On the other hand, in the present invention, as shown in FIG. 8A, the dielectric 10 is formed three-dimensionally from a resin material (PBT), and also functions as a housing for the antenna. By using a resin material, a dielectric having a complicated shape that also serves as a housing can be easily formed. A ground electrode 20 made of a metal plate is provided around the inner surface of the antenna housing recess 18 on the lower surface of the dielectric 10. An amplifier circuit 28 is provided in a space defined by the ground electrode 20 and the bracket 26. That is, the electromagnetic shield of the amplifier is achieved by the ground electrode 20 and the bracket 26. Since there is no need to additionally provide a shield case as in the related art, the structure is simple, the number of parts is small, and assembly is easy. Therefore, cost can be reduced and productivity can be improved.

[Reduction of Man-hours for Development Design] In the development design of an antenna, operations such as changing the electrode shape, adjusting the resonance frequency, and performing a measurement experiment are repeated. In the case of a conventional ceramic type antenna, it is necessary to re-fire the electrodes on the ceramic substrate in order to adjust the resonance frequency. Also in the case of a printed board type antenna, it is necessary to repeat the etching of the copper pattern many times. Therefore, development of the antenna has taken considerable time and effort.

On the other hand, in the case of the antenna according to the present embodiment, the shape of the electrode can be adjusted only by peeling the patch electrode, which is a metal plate, from the dielectric and attaching a different patch electrode. Preferably, a plurality of types of patch electrodes are prepared in advance, and the patch electrodes are sequentially replaced. Since the positioning boss and the positioning hole are provided, the positioning of the patch electrode can be easily performed. As described above, in the present embodiment, the optimum patch shape can be obtained more easily and in a shorter time than before, and the number of development steps can be greatly reduced.

[Improvement of Productivity by Selective Fitting of Patch] An antenna using a resin material for a dielectric is preferably manufactured by the following method.

Even if the shape of the dielectric is accurate, the variation in the dielectric constant of the resin material is generally relatively large. If the dispersion of the dielectric constant is large, the dispersion of the characteristics of the antenna also becomes large, and the product yield may be deteriorated.

Therefore, in this embodiment, a plurality of types of patch electrodes having slightly different sizes are prepared in the manufacturing process. Then, a desired electrode characteristic is obtained by selecting a patch electrode according to the dielectric constant of the resin material and combining them. That is, a relatively small patch electrode is selected when the dielectric constant of the resin material is large, and a large patch electrode is selected when the dielectric constant is small.

However, it is difficult to measure the dielectric constant of each dielectric. Therefore, attention is paid to the fact that the dielectric constant of the resin material varies in rod units. That is, the permittivity of the resin material of each lot is measured, and the permittivity is combined with an appropriate patch size.

As described above, according to the present embodiment, the variation in the dielectric constant of the resin material can be absorbed by selecting the size of the patch electrode, and the product yield of the antenna is improved, and thus the productivity is improved. Can be planned.

Further, according to this embodiment, the antenna can be made thinner. Originally, when the dielectric is thin, the resonance frequency range is narrowed, and the demand for the shape accuracy of the patch is increased. The synergistic effect of the thin dielectric and the variation in the dielectric constant of the resin material considerably degrades the antenna characteristics. However, according to the present invention, variations in the dielectric constant can be absorbed by selecting a patch. Therefore, the thickness of the dielectric can be reduced while maintaining sufficient antenna performance. Since the resin dielectric antenna tends to be thick, the advantage obtained by reducing the thickness is great.

[0063]

As described above, according to the present invention, high productivity can be obtained by positioning the patch electrode with respect to the dielectric while sufficiently satisfying the antenna performance.

Further, with a simple structure using the positioning boss, a function of preventing deformation of the electrode protection cover can be provided in addition to the positioning function.

Further, by forming the feeder line with a part of the conductor plate of the patch electrode in consideration of the impedance value, the productivity and reliability of the antenna can be improved.

Furthermore, a low elevation angle gain can be improved by a suitable shape of the ground electrode.

On the other hand, by selecting the patch size in accordance with the dielectric constant of the dielectric resin material, the productivity can be greatly improved.

[Brief description of the drawings]

FIG. 1 is a perspective view of an antenna according to an embodiment of the present invention.

FIG. 2 is a sectional view of the antenna of FIG. 1;

FIG. 3 is a diagram showing the relationship between the size of a positioning hole of a patch electrode and the impedance value of an electrode edge.

FIG. 4 is a diagram showing a modified example of the shape of a dielectric positioning boss.

FIG. 5 is a diagram showing a configuration in which a patch electrode and a feeder line are integrally formed.

FIG. 6 is a diagram illustrating a principle of improvement of a low elevation gain by the antenna according to the present embodiment.

FIG. 7 is a diagram showing the gain of the antenna of the present invention in comparison with a conventional antenna.

FIG. 8 is a diagram showing an amplifier shield structure of the antenna of the present invention in comparison with a conventional antenna.

[Explanation of symbols]

Reference Signs List 10 dielectric, 14 patch electrode, 18 amplifier receiving recess, 20 ground electrode, 20b vertical wall, 26 bracket, 28 preamplifier circuit, 30 power supply pin, 3
2 Electrode protection cover, 40 positioning boss, 50 positioning hole, 56 power supply line.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Kiyotaka Kumaki 3-30, Shimoichimachi, Toyota-shi, Aichi Prefecture Kojima Press Industry Co., Ltd. Press Industry Co., Ltd. (72) Inventor Minoru Yonebayashi 3-30, Shimoichimachi, Toyota City, Aichi Prefecture Kojima Press Industry Co., Ltd. F-term (reference) 5J045 AA01 AA21 AB06 AB08 DA10 EA07 EA08 HA03 LA01 MA04 NA01 NA06 5J046 AA04 AA09 AA14 AA19 AB03 BA03 PA07 QA02

Claims (5)

[Claims] 1. A dielectric body made of resin, and a patch electrode attached to the dielectric body, wherein the dielectric body has a polygonal positioning boss protruding from a central portion of an electrode attachment area, The patch electrode has a positioning hole into which the positioning boss is fitted, and the positioning hole is provided such that an impedance value of an edge of the positioning hole is equal to or less than an impedance value of an antenna circuit. Wherein the patch electrode is positioned with respect to the dielectric by the engagement of the antenna. 2. The antenna according to claim 1, wherein an electrode protection cover covering the patch electrode is provided with a gap between the patch electrode and the positioning electrode, and the positioning boss penetrates through the patch electrode. An antenna protruding from a surface and supporting the electrode protection cover. 3. The antenna according to claim 1, wherein the positioning hole is provided such that an impedance value of at least a part of an edge of the positioning hole is equal to an impedance value of the antenna circuit. Edges with equal values
An antenna, wherein a portion of the patch material plate corresponding to the positioning hole is bent to form an antenna feed line. 4. The antenna according to claim 1, further comprising: a ground electrode attached to a side of the dielectric opposite to the patch electrode, wherein the ground electrode sandwiches the dielectric. An antenna having a vertical surface perpendicular to the patch electrode at a position facing an outer peripheral edge of the patch electrode, wherein an electric field is generated between the patch electrode and the vertical surface. 5. A method of manufacturing an antenna by attaching a patch electrode to a resin dielectric, wherein a plurality of types of patch electrodes are prepared, and a patch having a size corresponding to the dielectric constant of the dielectric is prepared. An antenna manufacturing method, comprising selecting an electrode.