JP7514736B2 - Antenna Device - Google Patents

Description

The disclosure in this specification relates to an antenna device.

The planar antenna described in Patent Document 1 has an electromagnetic band-gap (EBG) structure between the antenna section and the ground plane. This improves the gain of the planar antenna in the thickness direction.

JP 2009-44697 A

In Patent Document 1, the gain in the thickness direction of the planar antenna is improved, but there is a problem in that the gain in the planar direction perpendicular to the thickness direction is small. For example, if the planar antenna of Patent Document 1 is installed on the ceiling of a vehicle so that the thickness direction of the planar antenna is vertical, gain in the vertical direction is obtained, but the gain in a specific direction in the horizontal plane is small. If the planar antenna of Patent Document 1 is installed on the ceiling of a vehicle so that the thickness direction of the planar antenna is in the horizontal plane, gain in a specific direction in the horizontal plane is obtained, but there is a problem in that the vertical dimension is large.

The disclosed object has been made in consideration of the above-mentioned problems, and aims to provide an antenna device that is thin and can improve the gain in a specific direction within a plane.

This disclosure employs the following technical means to achieve the above-mentioned objectives.

The antenna device disclosed herein comprises a dielectric substrate (12), a ground plane (11) arranged on the front surface of the dielectric substrate, a plurality of conductor patches (13) arranged periodically on the rear surface of the dielectric substrate, an antenna element (15) arranged on the rear surface of the dielectric substrate at a distance from the conductor patches, and a conductor object (14) arranged on the rear surface of the dielectric substrate at a distance from the conductor patches, the conductor object being arranged at a distance from the antenna element in the planar direction of the dielectric substrate, the distance between adjacent conductor patches and the size of the conductor patches being set so that the plurality of conductor patches resonate at the resonant frequency of the antenna element, and on the rear surface of the dielectric substrate, the conductor object side of the antenna element is defined as the inside of the antenna element, and the side opposite the conductor object side of the antenna element is defined as the outside of the antenna element, and the conductor patch arranged on the outside of the antenna element has a larger dimension than the conductor patch arranged directly below the antenna element and on the inside of the antenna element .
The antenna device disclosed herein also has a dielectric substrate (12), a ground plate (11) arranged on the front surface of the dielectric substrate, a plurality of conductor patches (13) arranged periodically on the rear surface of the dielectric substrate, an antenna element (15) arranged on the rear surface side of the dielectric substrate at a distance from the conductor patches, and a conductor object (14) arranged on the rear surface side of the dielectric substrate at a distance from the conductor patches, the conductor object being arranged at a distance from the antenna element in the planar direction of the dielectric substrate, the distance between adjacent conductor patches and the size of the conductor patches being set so that the plurality of conductor patches resonate at the resonant frequency of the antenna element, and the dielectric substrate is smaller than the ground plate and is arranged at the end of the ground plate.
The antenna device disclosed herein further comprises a dielectric substrate (12), a ground plate (11) arranged on the front surface of the dielectric substrate, a plurality of conductor patches (13) arranged periodically on the rear surface of the dielectric substrate, an antenna element (15) arranged on the rear surface side of the dielectric substrate at a distance from the conductor patches, and a conductor object (14) arranged on the rear surface side of the dielectric substrate at a distance from the conductor patches, the conductor object being arranged at a distance from the antenna element in the planar direction of the dielectric substrate, the distance between adjacent conductor patches and the size of the conductor patches being set so that the plurality of conductor patches resonate at the resonant frequency of the antenna element, the ground plate being a metal roof of a vehicle (20), and the dielectric substrate being an antenna device arranged on the roof.
The antenna device disclosed herein also has a dielectric substrate (12), a ground plate (11) arranged on the front surface of the dielectric substrate, a plurality of conductor patches (13) arranged periodically on the rear surface of the dielectric substrate, an antenna element (15) arranged on the rear surface side of the dielectric substrate at a distance from the conductor patches, and a conductor object (14) arranged on the rear surface side of the dielectric substrate at a distance from the conductor patches, the conductor object being arranged at a distance from the antenna element in the planar direction of the dielectric substrate, the distance between adjacent conductor patches and the size of the conductor patches being set so that the plurality of conductor patches resonate at the resonant frequency of the antenna element, the conductor object being plate-shaped, and the antenna device further having another antenna element on the surface of the conductor object opposite the dielectric substrate.

According to such an antenna device, multiple conductor patches are periodically arranged on the dielectric substrate so as to resonate at the resonant frequency of the antenna element, and the reflected wave phase is in-phase reflection at the resonant frequency. This allows the antenna element to be brought closer to the ground plane, making it possible to reduce the thickness. If the specific direction is defined as one direction within the plane of the dielectric substrate, the conductor is arranged at a distance from the antenna element in the planar direction, and the reflection of the conductor can improve the gain in the specific direction on the opposite side of the antenna element to the conductor. This makes it possible to improve the gain in the specific direction. Therefore, it is possible to realize an antenna device that is thin and can improve the gain in a specific direction within the plane.

The symbols in parentheses for each of the above means are examples showing the correspondence with the specific means described in the embodiments described below.

FIG. 2 is a plan view showing the antenna device 10 according to the first embodiment. 2 is a cross-sectional view taken along line II-II in FIG. 1 . FIG. 1 is a plan view showing a first embodiment of an antenna device 10. FIG. 2 is an enlarged cross-sectional view showing a part of the first embodiment. 11 is a graph showing an example of the relationship between the distance d and the gain. 6 is a waveform showing the directivity of the antenna element 15 of the first embodiment. 13 is a waveform showing the directivity of an antenna element 15 according to the second embodiment. FIG. 11 is an enlarged plan view showing a portion of the antenna device 10 according to the second embodiment. 13 is a waveform showing the directivity of the antenna element 15 of the third embodiment. FIG. 13 is a diagram showing a mounted state of the antenna device 10 according to the third embodiment. FIG. 2 is a plan view showing the antenna device 10. 12 is a cross-sectional view taken along the line XII-XII in FIG. 11 . 11 is a waveform showing the directivity of each of antenna elements 15a and 15b according to the fourth embodiment. FIG. 11 is a plan view showing another antenna device 10 according to the third embodiment. 13 is a waveform showing the directivity of each of antenna elements 15a and 15b according to the fifth embodiment. FIG. 11 is a plan view showing another shape of the conductor plate 14. 11 is a plan view showing another shape of the conductor patch 13. FIG.

Below, with reference to the drawings, a number of embodiments for implementing the present disclosure will be described. In each embodiment, the same reference numerals will be used for parts that correspond to matters described in the preceding embodiment, or one character may be added to the preceding reference numeral, and duplicate explanations may be omitted. Furthermore, when part of the configuration is described in each embodiment, the other parts of the configuration will be the same as in the embodiment described previously. It is possible to combine not only the parts specifically described in each embodiment, but also partially combine embodiments together, provided that no particular hindrance occurs to the combination.

First Embodiment
An antenna device 10 according to a first embodiment of the present disclosure will be described with reference to Figs. 1 to 7. The antenna device 10 is connected to a radio device, for example, via a coaxial cable (not shown), and signals received by the antenna device 10 are sequentially output to the radio device. The antenna device 10 also converts electrical signals input from the radio device into radio waves and radiates the radio waves into space. The radio device uses the signals received by the antenna device 10 and supplies high-frequency power to the antenna device 10 according to the transmission signal. As a power supply line to the antenna device 10, other power supply lines such as a feeder line may be used in addition to the coaxial cable.

The antenna device 10 is configured to transmit and receive radio waves of a specified target frequency. In another embodiment, the antenna device 10 may be used for only one of transmission and reception. Since radio wave transmission and reception are reversible, a configuration capable of transmitting radio waves of a frequency is also a configuration capable of receiving radio waves of that frequency.

The target frequency is appropriately designed, and in this embodiment, it is the 28 GHz band, which is one of the frequency bands allocated to the fifth generation mobile phone communication system. As shown in Figures 1 and 2, the antenna device 10 of this embodiment is composed of a ground plane 11, a dielectric substrate 12, a conductor patch 13, a conductor plate 14, and an antenna element 15.

The antenna device 10 is capable of radiating radio waves of a target frequency, at least those with a plane of polarization parallel to the ground plate 11. The antenna device 10 may also be capable of radiating radio waves with a plane of polarization perpendicular to the ground plate 11. When the ground plate 11 is disposed horizontally, radio waves with a plane of polarization parallel to the ground plate 11 are horizontally polarized, and radio waves with a plane of polarization perpendicular to the ground plate 11 are vertically polarized.

Although not shown in Figures 1 and 2, the antenna device 10 is provided with a cover that covers the entire device as appropriate. The X-axis shown in Figure 1 etc. extends in the left-right direction of Figure 1 and indicates the width direction of the base plate 11. The Y-axis extends in the up-down direction of Figure 1 and indicates the longitudinal direction of the base plate 11. The Z-axis extends in a direction perpendicular to the paper surface of Figure 1 and indicates the thickness direction of the base plate 11.

The antenna device 10 is generally flat. The shape of the antenna device 10 in a plan view is square. A plan view means that the antenna device 10 is viewed in a direction from the conductor plate 14 toward the ground plate 11, as in FIG. 1. The ground plate 11 is made of a conductive material and is larger than the conductor plate 14.

The dielectric substrate 12 is made of resin and is configured in a flat plate shape. The dielectric substrate 12 has a relative dielectric constant of, for example, 3.62. The ground plane 11 is disposed on the surface of the resin dielectric substrate 12, the lower surface in FIG. 2. The ground plane 11 and the dielectric substrate 12 are approximately the same size.

A plurality of conductor patches 13 are arranged on the back surface of the dielectric substrate 12, the upper surface in FIG. 2. The conductor patches 13 and the ground plane 11 are arranged on different surfaces in the thickness direction of the dielectric substrate 12. As shown in FIG. 1, the conductor patches 13 are each square-shaped and arranged in a matrix with a gap between them. The conductor patches 13 are set so that the gap between adjacent conductor patches 13, the size of the conductor patches 13, and the distance between the conductor patches 13 and the ground plane 11 resonate at the resonant frequency of the antenna element 15. Specifically, the distance between adjacent conductor patches 13 and the ground plane 11 of the conductor patches 13 can be regarded as the capacitance component of a capacitor. The size of the conductor patches 13 can be regarded as the inductor component. Therefore, the periodically arranged conductor patches 13 can be considered as a continuous LC resonant circuit due to the capacitance component generated between each conductor patch 13 and the inductor component of each conductor patch 13, and resonate in parallel at a predetermined frequency. The frequency at which the conductor patches 13 resonate in parallel is set to be the resonant frequency of the antenna element 15. With conductor patches 13 having such a periodic structure, the electromagnetic waves incident on the multiple conductor patches 13 and the reflected electromagnetic waves are in phase. Because the phases are the same, the electromagnetic waves reflected by the multiple conductor patches 13 and the incident electromagnetic waves reinforce each other. Therefore, the multiple conductor patches 13 form a so-called EGB structure on the back surface of the dielectric substrate 12.

The antenna element 15 is disposed on the back side of the dielectric substrate 12, or on the upper side in FIG. 2, at a distance from the conductor patch 13. In this embodiment, the antenna element 15 is realized by a dipole antenna. The antenna element 15 is fed from a central feeding point, as shown in FIG. 1.

The conductor plate 14 is a conductor and is arranged on the back side of the dielectric substrate 12, or on the upper side in FIG. 2, at a distance from the conductor patch 13. The conductor plate 14 is supported by a plurality of resin columns (not shown). Therefore, the space between the dielectric substrate 12 and the conductor plate 14 is hollow. A resin substrate made of resin may be inserted between the conductor plate 14 and the dielectric substrate 12. A honeycomb structure or the like may be used as the resin substrate. When the antenna device 10 is realized using a printed wiring board, the plurality of conductor layers of the printed wiring board may be used as the conductor patch 13 and the conductor plate 14, and the resin layer separating the conductor layers may be used as the resin substrate.

The conductor plate 14 is a plate-shaped conductor member made of a conductor such as copper. The plate-shaped member also includes a thin film such as copper foil. The conductor plate 14 is smaller than the ground plate 11 in a plan view, and faces the ground plate 11 in the thickness direction via the dielectric substrate 12. The conductor plate 14 is approximately parallel to the ground plate 11. Approximately parallel includes parallel, and also includes a state inclined by several degrees to about 10 degrees, which is not limited to completely parallel. The size of the conductor plate 14 may be any size that reflects the radio waves emitted by the antenna element 15. Therefore, the conductor plate 14 is set to be at least larger than the antenna element 15.

The conductor plate 14 is disposed with a gap between it and the antenna element 15 in the planar direction of the dielectric substrate 12. The planar direction is one direction in an imaginary plane parallel to the rear surface of the dielectric substrate 12, for example, the left-right direction and the up-down direction in FIG. 2. As shown in FIG. 2, the antenna element 15 and the conductor plate 14 are adjacent to each other at the same height in the up-down direction from the dielectric substrate 12.

Figures 3 and 4 show an embodiment of the antenna device 10. The specific shape of the antenna device 10 will be described using Figures 3 and 4. If the analysis frequency is 27.5 GHz in the 28 GHz band, the wavelength λ is 10.9 mm in a vacuum. Therefore, the wavelength λ of the resonant frequency of the antenna element 15 is set to, for example, 10.9 mm.

Under these conditions, as shown in FIG. 3, three rows of conductor patches 13 are arranged on the outside of the conductor plate 14. The conductor patches 13 have, for example, a side length of 2.35 mm and a period of 2.8 mm so that they resonate at the resonant frequency. Therefore, the spacing between adjacent conductor patches 13 is 0.45 mm.

If the wavelength at the resonant frequency of the antenna element 15 is λ, the distance d between the antenna element 15 and the conductor plate 14 is set to less than λ/3, and in this embodiment, it is set to λ/4. In addition, the height h from the ground plate 11 to the conductor plate 14 is set to 0.09λ.

As shown in FIG. 5, the distance d is set based on the unit gain of the dipole antenna. As shown in FIG. 5, the simulation results show that as the distance d is increased, the maximum gain in the horizontal plane gradually decreases. The horizontal plane is the surface along which the dielectric substrate 12 of the antenna device 10 is aligned when it is installed horizontally. If the theoretical gain of the dipole antenna is 2.15 dBi, then if the distance d is λ/3 or more, it will be smaller than 2.15 dBi. Therefore, the distance d is set to less than λ/3. If the distance d is less than about 0.7 mm, the gain will fall below 2.15 dBi, so it is preferably 0.7 mm or more. Therefore, the distance d is preferably 1 mm or more and 2 mm or less so that the gain is higher than 4 dBi, and more preferably 1.5 mm.

Figure 6 shows the results of a simulation of antenna directivity. Comparative Example 1 is an antenna device without an EGB structure, and Comparative Example 2 is an antenna device without an EGB structure and without a conductor plate 14. In Figure 6, the dashed line is Comparative Example 1, the dashed line is Comparative Example 2, and the solid line is the antenna device 10 of Example 1. As shown in Figure 6, it can be seen that in the ZX plane, Example 1 has directivity slightly to the right of directly above. It can also be seen that in the XY plane, there is directivity to the right. Comparative Example 2 has a higher directivity to the right than Comparative Example 1. Therefore, the directivity to the right is improved by just the EGB structure, but by arranging the conductor plate 14 as in Example 1, the directivity to the right is further improved.

Figure 7 shows the simulation results for Example 2, in which the base plate 11 is curved in an upwardly convex shape. It can be seen that even in a configuration in which the base plate 11 is curved, the directivity to the right is improved. Therefore, for example, even in a configuration that is curved like the roof of a vehicle, the directivity can be improved.

As described above, the antenna device 10 of this embodiment has multiple conductor patches 13 periodically arranged on the dielectric substrate 12 so as to resonate at the resonant frequency of the antenna element 15, so that the reflected wave phase becomes in-phase reflection at the resonant frequency, making it difficult for surface current to flow. Therefore, even if multiple conductor patches 13 are made to function as reflectors, the electrical characteristics are not easily deteriorated, so the antenna element 15 can be brought closer to the ground plate 11 and can be made thinner. Here, if the specific direction is one direction in the plane of the conductor plate 14, the conductor plate 14 is arranged at a distance from the antenna element 15, so that the reflection of the conductor plate 14 can improve the gain in the specific direction on the opposite side of the conductor plate 14 of the antenna element 15. This can improve the gain in the specific direction. Therefore, it is possible to realize an antenna device 10 that is thin and can improve the gain in a specific direction in a plane.

In this embodiment, the antenna element 15 and the conductor plate 14 are adjacent to each other, and the distance d between the antenna element 15 and the conductor plate 14 is less than λ/3. By making the distance d less than λ/3, the gain can be exceeded by the single gain of a dipole antenna. The distance d is preferably set to λ/4. The smaller the distance d, the better the gain tends to be, but the antenna element 15 is arranged so that there is at least a distance therebetween, in other words, so that the antenna element 15 and the conductor plate 14 do not come into contact with each other.

Second Embodiment
Next, a second embodiment of the present disclosure will be described with reference to Figs. 8 and 9. This embodiment is characterized in that the size of the conductor patch 13A is not uniform. Specifically, on the back surface of the dielectric substrate 12, the conductor plate 14 side of the antenna element 15 is the inside of the antenna element 15, and the opposite side of the conductor plate 14 of the antenna element 15 is the outside of the antenna element 15. In Fig. 8, the left side of the antenna element 15 is the inside, and the right side of the antenna element 15 is the outside. The conductor patch 13A arranged on the outside of the antenna element 15 is larger than the dimensions of the conductor patch 13A arranged directly below the antenna element 15 and on the inside of the antenna element 15. Therefore, the dimension L2 of the outer conductor patch 13A shown in Fig. 8 is larger than the dimension L1 of the inner conductor patch 13A (L2>L1).

The outer conductor patch 13A is also periodically configured, so that it resonates at a different frequency from the inner conductor patch 13A. Since the outer conductor patch 13A is large, the resonating frequency f1 is smaller than the resonant frequency f0 of the inner conductor patch 13 (f0<f1). There is a gap between the horizontally polarized wave propagation region and the vertically polarized wave propagation region at the resonant frequency of the antenna element 15 and the EBG structure, and horizontally polarized waves tend to propagate in the high resonant frequency region, and vertically polarized waves tend to propagate in the low resonant frequency region. In this embodiment, the resonant frequency f0 of the inner conductor patch 13A is set in the gap between the horizontally polarized wave propagation region and the vertically polarized wave propagation region. As a result, neither horizontal nor vertical polarization is likely to occur at the resonant frequency f0, so that the conductor plate 14 and the conductor patch 13 can be brought closer together. However, in order to improve the directivity of the outer conductor patch 13, it is desirable to set the resonant frequency in the horizontally polarized wave propagation region so that horizontally polarized waves tend to propagate as described above. Therefore, by making the outer resonant frequency f1 smaller than the resonant frequency f0, the propagation region of the horizontally polarized wave at the resonant frequency f0 becomes the resonant frequency f0, and surface waves become more easily propagated on the outside.

Figure 9 shows the results of a simulation of the antenna directivity. Example 1 has the configuration of the examples described in the first embodiment above, i.e., the sizes of the conductor patches 13 are equal. Example 3 is an antenna device 10 that uses two types of conductor patches 13A and has L1 = 2.35 mm and L2 = 2.55 mm. In Figure 9, the dashed line is Example 3, and the solid line is the antenna device 10 of Example 1. As shown in Figure 9, it can be seen that in the ZX plane, Example 1 has directivity slightly to the right of directly above, while Example 3 has directivity further to the right. It can also be seen that in the XY plane, Example 3 has directivity to the right more than Example 1.

In this manner, in this embodiment, two types of conductor patches 13A are used, and the dimension L2 of the outer conductor patch 13A is made larger than the dimension L1 of the inner conductor patch 13A, thereby further improving the directivity.

Third Embodiment
Next, a third embodiment of the present disclosure will be described with reference to Figs. 10 to 15. As shown in Fig. 10, this embodiment is characterized in that the roof of a vehicle 20 is used as a base plate 11B. The roof of the vehicle 20 is made of metal and is called a roof. In this embodiment, the base plate 11B is a metal roof. And, as shown in Figs. 11 and 12, the dielectric substrate 12 is disposed on the roof. The dielectric substrate 12 is smaller than the roof, and as shown in Fig. 11, the roof extends around the periphery of the dielectric substrate 12 in plan view.

Furthermore, multiple antenna elements 15 are arranged around the conductor plate 14, two in this embodiment. The two antenna elements 15 are arranged facing each other in the fore-and-aft direction of the vehicle 20. Hereinafter, the antenna element 15 on the front side of the vehicle 20, i.e., the left side in FIG. 12, may be referred to as the first antenna element 15a, and the antenna element 15 on the rear side of the vehicle 20, i.e., the right side in FIG. 12, may be referred to as the second antenna element 15b.

Figure 13 shows the results of a simulation of the antenna directivity of the first antenna element 15a and the second antenna element 15b. Comparative example 3 is an antenna device that does not have an EGB structure and does not have a conductor plate 14. In Figure 13, the dashed line represents comparative example 3, and the solid line represents the antenna device 10 of Example 4 of this embodiment. As shown in Figure 13, in the ZX plane, it can be seen that with the first antenna element 15a, Example 4 has directivity slightly to the left of directly above, and with the second antenna element 15b, Example 4 has directivity slightly to the right of directly above. It can therefore be seen that the directivity on the side where the antenna element 15 is placed is improved.

In this embodiment, the dielectric substrate 12 is disposed at a position other than the edge of the roof of the vehicle 20, but the present invention is not limited to this configuration. For example, the dielectric substrate 12 may be smaller than the roof, which is the base plate 11B, and may be disposed at the edge of the roof. Therefore, if the dielectric substrate 12 is square as shown in FIG. 11, for example, one side may be located at the edge of the roof, as shown in FIG. 14. The part following the edge of the roof is, for example, window glass and is not metal.

Figure 15 shows the results of a simulation of the antenna directivity of the first antenna element 15a and the second antenna element 15b when placed on such a roof, i.e., the end of the ground plate 11B. Comparative example 3 is an antenna device that does not have an EGB structure and further does not have a conductor plate 14. In Figure 15, the dashed line is Comparative example 3, and the solid line is the antenna device 10 of Example 5 shown in Figure 14. As shown in Figure 15, in the ZX plane, the results for the first antenna element 15a are the same as those in Figure 12 above. For the second antenna element 15b, it can be seen that Example 5 has directivity slightly to the right of directly above compared to Comparative example 3. Therefore, it can be seen that even at the end of the ground plate 11B, the directivity on the side where the antenna element 15 is placed is improved.

Other Embodiments
Although the preferred embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments and can be modified in various ways without departing from the spirit and scope of the present disclosure.

The structures of the above-described embodiments are merely examples, and the scope of the present disclosure is not limited to the scope of these descriptions. The scope of the present disclosure is indicated by the description of the claims, and further includes all modifications within the meaning and scope equivalent to the description of the claims.

In the first embodiment described above, there is one antenna element 15, and the conductive plate 14 is square-shaped, but the present invention is not limited to this configuration, and as shown in FIG. 16, there may be multiple antenna elements 15. The antenna element 15 may be oriented in the direction in which the directivity is desired. As shown in FIG. 16, the conductive plate 14 may be of other shapes, such as an equilateral triangle, a regular octagon, or a circle. The conductive plate 14 may also be rectangular or oblong.

In the first embodiment described above, the conductor patch 13 is square-shaped, but this is not limited to the configuration, and as shown in FIG. 17, the conductor patch 13 may be of other shapes, such as rectangular, polygonal, or circular.

In the first embodiment described above, no antenna element is provided on the surface in the thickness direction of the conductor plate 14, but another antenna element may be provided, for example, on the surface of the conductor plate 14 opposite the dielectric substrate 12. The other antenna element is an antenna element that receives vertically polarized waves, for example, an antenna element that receives navigation signals transmitted from positioning satellites that make up the Global Navigation Satellite System (GNSS).

In the first embodiment described above, the antenna element 15 is realized by a dipole antenna, but this is not limited to a dipole antenna and may be another antenna element, such as a loop antenna.

In the first embodiment described above, the conductor is realized by a plate-shaped member such as the conductor plate 14, but it is not limited to being plate-shaped. When there is only one antenna element 15, the conductor may be a rod-shaped or rectangular member, etc., as long as there is a portion that faces the antenna element 15 and reflects radio waves from the antenna element 15. Even when there are multiple antenna elements 15, the conductor may be a hollow frame-shaped member rather than a plate-shaped member.

10...antenna device 11...ground plate 12...dielectric substrate 13...conductor patch 14...conductor plate (conductor object) 15...antenna element 15a...first antenna element 15b...second antenna element 20...vehicle

Claims (10)

A dielectric substrate (12);
A ground plane (11) disposed on the surface of the dielectric substrate;
A plurality of conductor patches (13) periodically arranged on the rear surface of the dielectric substrate;
an antenna element (15) disposed on the back side of the dielectric substrate at a distance from the conductor patch;
A conductor object (14) is disposed on the back side of the dielectric substrate at a distance from the conductor patch,
the conductor is disposed at a distance from the antenna element in a planar direction of the dielectric substrate,
the spacing between adjacent conductor patches and the size of the conductor patches are set so that the plurality of conductor patches resonate at a resonance frequency of the antenna element;
On the back surface of the dielectric substrate, the conductor side of the antenna element is defined as the inside of the antenna element, and the opposite side of the antenna element to the conductor side is defined as the outside of the antenna element.
An antenna device in which the conductor patch arranged outside the antenna element has a larger dimension than the conductor patch arranged directly below the antenna element and inside the antenna element . A dielectric substrate (12);
A ground plane (11) disposed on the surface of the dielectric substrate;
A plurality of conductor patches (13) periodically arranged on the rear surface of the dielectric substrate;
an antenna element (15) disposed on the back side of the dielectric substrate at a distance from the conductor patch;
A conductor object (14) is disposed on the back side of the dielectric substrate at a distance from the conductor patch,
the conductor is disposed at a distance from the antenna element in a planar direction of the dielectric substrate,
the spacing between adjacent conductor patches and the size of the conductor patches are set so that the plurality of conductor patches resonate at a resonance frequency of the antenna element;
The antenna device has a dielectric substrate that is smaller than the ground plane and is disposed at an end of the ground plane . A dielectric substrate (12);
A ground plane (11) disposed on the surface of the dielectric substrate;
A plurality of conductor patches (13) periodically arranged on the rear surface of the dielectric substrate;
an antenna element (15) disposed on the back side of the dielectric substrate at a distance from the conductor patch;
A conductor object (14) is disposed on the back side of the dielectric substrate at a distance from the conductor patch,
the conductor is disposed at a distance from the antenna element in a planar direction of the dielectric substrate,
the spacing between adjacent conductor patches and the size of the conductor patches are set so that the plurality of conductor patches resonate at a resonance frequency of the antenna element;
The base plate is a metal roof of a vehicle (20),
The antenna device , wherein the dielectric substrate is disposed on the roof . A dielectric substrate (12);
A ground plane (11) disposed on the surface of the dielectric substrate;
A plurality of conductor patches (13) periodically arranged on the rear surface of the dielectric substrate;
an antenna element (15) disposed on the back side of the dielectric substrate at a distance from the conductor patch;
A conductor object (14) is disposed on the back side of the dielectric substrate at a distance from the conductor patch,
the conductor is disposed at a distance from the antenna element in a planar direction of the dielectric substrate,
the spacing between adjacent conductor patches and the size of the conductor patches are set so that the plurality of conductor patches resonate at a resonance frequency of the antenna element;
The conductor is plate-shaped,
The antenna device further includes another antenna element on a surface of the conductor opposite to the dielectric substrate . On the back surface of the dielectric substrate, the conductor side of the antenna element is defined as the inside of the antenna element, and the opposite side of the antenna element to the conductor side is defined as the outside of the antenna element.
5. The antenna device according to claim 2, wherein the conductor patch arranged on the outer side of the antenna element is larger in size than the conductor patches arranged immediately below the antenna element and on the inner side of the antenna element. 5. The antenna device according to claim 1, wherein the dielectric substrate is smaller than the ground plane and is disposed at an end of the ground plane. The base plate is a metal roof of a vehicle (20),
The antenna device according to claim 1 , 2 or 4 , wherein the dielectric substrate is disposed on the roof. The conductor is plate-shaped,
4. The antenna device according to claim 1, further comprising another antenna element on a surface of the conductor opposite to the dielectric substrate. the antenna element is a dipole antenna,
9. The antenna device according to claim 1, wherein , when the wavelength at the resonant frequency of the antenna element is λ, the distance between the antenna element and the conductor is less than λ/3. The antenna device according to any one of claims 1 to 9 , wherein a plurality of the antenna elements are arranged around the conductor object.