CN113745811A

CN113745811A - Antenna device

Info

Publication number: CN113745811A
Application number: CN202110577620.1A
Authority: CN
Inventors: 工藤茂树; 小林龙治
Original assignee: Harada Industry Co Ltd
Current assignee: Harada Industry Co Ltd
Priority date: 2020-05-27
Filing date: 2021-05-26
Publication date: 2021-12-03
Also published as: JP7162033B2; JP2021190756A

Abstract

The invention provides an antenna device, which improves the directivity of the antenna device comprising a patch antenna. An antenna device (1) is provided with: a substrate (16), wherein the substrate (16) has a ground region (17) on the surface; and a patch antenna (18), wherein the patch antenna (18) is provided on the surface side of the substrate (16). The patch antenna (18) is provided with a ground element (34), an antenna element (32), a power supply unit (36), and a ground connection unit (40). The grounding element (34) is disposed so as to be inclined with respect to the substrate (16) such that the front end side is close to the substrate (16) and the rear end side is distant from the substrate (16). The antenna element (32) extends substantially parallel to the ground element (34). The power supply section (36) extends from the front end of the antenna element (32). The ground connection portion (40) extends from the front end of the ground element (34) and is connected to the ground region (17).

Description

Antenna device

Technical Field

The present invention relates to a ground structure of a patch antenna.

Background

With the improvement of vehicle performance and design, antenna devices in which a plurality of antennas are housed in a common housing have become popular (see, for example, patent document 1). In recent vehicles, antennas compatible with various uses such as gps (global Positioning system) for providing position Information and etc (electronic Toll Collection system) and vics (vehicle Information and Communication system) for realizing its (intelligent Transport systems) have been standardized. These multiple antennas are housed in one case. Note that ETC and VICS are registered trademarks, and their descriptions are omitted in the following description.

In the antenna device described in patent document 1, a 1 st antenna for ETC and a 2 nd antenna for GPS are housed in a common housing. Either antenna is constituted by a so-called patch antenna. In order to communicate with an infrastructure (roadside machine) in front of the vehicle, the 1 st antenna is required to have a directivity in the forward direction. On the other hand, in order to receive radio waves from an infrastructure (satellite) above the vehicle, the 2 nd antenna is required to have a wide range of directivity around the zenith direction. Therefore, the 2 nd antenna is disposed horizontally with respect to the housing, and the 1 st antenna is disposed obliquely with respect to the horizontal direction.

In this way, when a plurality of antennas are housed in one housing, it is necessary to save space in the housing. Therefore, a configuration has been proposed in which a common connector for connecting to an external device is provided on one circuit board, and an element of an antenna requiring an elevation angle is separated therefrom (see, for example, patent document 2).

In the antenna device described in patent document 2, the 2 nd antenna is provided on the circuit board, and the element of the 1 st antenna is separated therefrom. The element and the circuit board are connected by a coaxial cable. The inner conductor of the coaxial cable is used for power supply and the outer conductor is used for grounding. The ground wiring provided on the circuit board and the ground point of the element provided on the 1 st antenna are connected by their ground lines. An auxiliary grounding cable is provided for connecting a further grounding point of the element provided in the 1 st antenna to the grounding wiring of the circuit board. By disposing the coaxial cable and the auxiliary ground cable substantially symmetrically with respect to the center line of the circuit board, the deviation of the directivity of the 1 st antenna is alleviated.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2011-130115

Patent document 2: japanese patent laid-open publication No. 2015-185908

Disclosure of Invention

Problems to be solved by the invention

In addition, the patch antenna can obtain good directivity when the radiating element (antenna element) and the chassis (ground element) are both square and have symmetrical shapes. In this regard, if the ground line of the 1 st antenna is formed of a cable as described above, the bottom plate portion extends in an unnatural shape, and it is difficult to ensure symmetry. As a result, there is room for improvement such as a left-right imbalance in the directivity of the antenna.

The present invention has been made in view of the above problems, and an object thereof is to improve the directivity of an antenna device including a patch antenna.

Means for solving the problems

One technical solution of the present invention is an antenna apparatus. The antenna device comprises a substrate with a grounding area and a patch antenna arranged on the substrate. The patch antenna includes a ground element, an antenna element, a power supply portion, and a ground connection portion. The ground element is disposed obliquely with respect to the substrate so that the front end side is close to the substrate and the rear end side is distant from the substrate. The antenna element extends substantially parallel to the ground element. The feeding portion extends from the front end of the antenna element. The ground connection portion extends from the front end of the ground element and is connected to the ground region.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, the directivity of the antenna device including the patch antenna can be improved.

Drawings

Fig. 1 is an exploded perspective view of an antenna device according to an embodiment.

Fig. 2 is a diagram showing the structure of the antenna unit.

Fig. 3 is a central longitudinal sectional view showing an internal structure of the antenna device.

Fig. 4 is a diagram showing the structure of the ETC antenna and its periphery in detail.

Fig. 5 is a diagram showing a radiation pattern of a radio wave.

Fig. 6 is a diagram showing the influence of the position of the ETC antenna on the radiation pattern.

Fig. 7 is a diagram showing the influence of the position of the ETC antenna on the radiation pattern.

Fig. 8 is a diagram showing the influence of the shape of the TEL antenna on the radiation pattern.

Description of the reference numerals

1. An antenna device; 10. an antenna unit; 12. a substrate; 13. an antenna base unit; 14. a cover; 16. a circuit substrate; 17. a ground region; 18. an ETC antenna; 20. a GPS antenna; 22. a TEL antenna; 24. a connector; 26. a through hole; 28. a screw; 30. a screw; 32. an antenna element; 34. a ground element; 36. a power supply unit; 38. a through hole; 40. a ground connection portion; 42. an antenna element; 44. a power supply unit; 46. 1 st extension part; 48. a 2 nd extension part; 50. an opening part; 52. a shield case; 54. a conducting sheet; 56. a through hole; 60. a support table; 70. the 1 st surface; 72. the 2 nd surface; 74. and (3) a third surface.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following embodiments and modifications thereof, the same reference numerals are given to substantially the same components, and descriptions thereof are omitted as appropriate.

In the present embodiment, an antenna device for a vehicle (hereinafter, simply referred to as "antenna device") having a patch antenna is exemplified. Since the patch antenna is required to have a directivity in the forward direction in order to communicate with a roadside device in front of the vehicle, the antenna element is disposed to be inclined with respect to a horizontal plane. In order to improve the directivity of the patch antenna, a ground connection structure has been studied. The details thereof are explained below.

Fig. 1 is an exploded perspective view of an antenna device according to an embodiment. In the following description, for convenience, the positional relationship of the antenna device may be expressed in the front-rear, vertical, and width directions with reference to the vehicle-mounted state.

The antenna device 1 includes: an antenna unit 10 including a plurality of antennas; a substrate 12 on which the antenna unit 10 is mounted; and a cover 14 that houses the antenna unit 10 between the cover 14 and the substrate 12. The antenna unit 10 is configured by mounting an ETC antenna 18, a GPS antenna 20, and a TEL antenna 22 on a circuit board 16. The circuit board 16 functions as a "substrate".

The ETC antenna 18 is an antenna for ETC, and functions as a "1 st patch antenna". The GPS antenna 20 is an antenna for GPS and functions as a "2 nd patch antenna". The TEL antenna 22 is an antenna for a telephone, and includes a main antenna 22a and a sub-antenna 22b disposed symmetrically with respect to the circuit board 16. By providing a plurality of TEL antennas 22, it is possible to correspond to lte (long Term evolution) and mimo (Multiple Input Multiple output). A connector 24 is provided projecting from the lower surface of the front end portion of the circuit board 16, and the connector 24 has a power supply port for each antenna.

The substrate 12 is made of metal, and a through hole 26 is provided at a front end portion of the substrate 12. The cover 14 is made of a radio wave-permeable resin (e.g., ABS, PET, PC, etc.). The antenna unit 10 is mounted on the substrate 12 with the connector 24 inserted through the through hole 26, and the antenna unit 10 and the substrate 12 are fixed by a pair of screws 28. The cover 14 is attached to the substrate 12 so as to cover the antenna unit 10 from above, and the cover 14 and the substrate 12 are fixed by a pair of screws 30, thereby obtaining the antenna device 1. The antenna device 1 is mounted on an instrument panel or the like of a vehicle (not shown) (see patent document 2 and the like).

Fig. 2 is a diagram showing the structure of the antenna unit 10. Fig. 2 (a) is a perspective view as viewed from above (obliquely forward), and fig. 2 (B) is a perspective view as viewed from below (obliquely rearward).

As shown in fig. 2 (a), the circuit board 16 is a printed wiring board, and the width of the front half is larger than the width of the rear half. The circuit board 16 has a symmetrical shape with respect to the center line L. A ground region 17 is provided on the surface of the circuit board 16.

An ETC antenna 18, a GPS antenna 20, and a TEL antenna 22 are provided on the front surface side of the circuit board 16. The ETC antenna 18 and the GPS antenna 20 are arranged in front and rear along the center line L of the circuit board 16. The ETC antenna 18 has a higher frequency band than the GPS antenna 20. In the present embodiment, the former is a 5.8GHz band, and the latter is a 1.5GHz band. The pair of TEL antennas 22 are disposed on both the left and right sides with the ETC antenna 18 interposed therebetween. The center frequency of the TEL antenna 22 can be arbitrarily selected, for example, 800MHz, 1.7GHz, 2.6GHz, and the like.

ETC antenna 18 includes an antenna element 32 and a ground element 34. The ground element 34 is a rectangular conductive plate, and is disposed obliquely with respect to the circuit board 16 so that the front end side is close to the circuit board 16 and the rear end side is distant from the circuit board 16. The antenna element 32 is a rectangular conductive plate and constitutes a radiation electrode. The antenna element 32 extends substantially parallel to the ground element 34 directly above the ground element 34.

The ETC antenna 18 is a single-point feed type circularly polarized wave patch antenna. Thus, the corner of the antenna element 32 is cut into degenerate separation elements. A feeding portion 36 extends downward from the distal end of the antenna element 32. The base end of the feeding portion 36 is located on the center line of the antenna element 32. The power supply portion 36 penetrates a through hole 38 formed in the circuit board 16 and is connected to a power supply line (not shown) attached to the back surface of the circuit board 16.

A pair of ground connection portions 40 extend downward from the front end of the ground element 34. The center of the front end of the ground element 34 is bifurcated by a pair of ground connection portions 40. These ground connection portions 40 are disposed on the left and right sides with the power feeding portion 36 interposed therebetween, and are connected to the ground regions 17 of the circuit board 16, respectively. The antenna element 32 passes through the through hole 38 and is not in contact with the ground region 17.

The GPS antenna 20 is disposed behind the ETC antenna 18. The GPS antenna 20 is a dielectric patch antenna, and is configured by disposing a radiation electrode on the surface of a dielectric layer. The radiation electrode is disposed in parallel with the circuit board 16. The radiation electrode is provided with a power supply point. A through hole penetrating the dielectric layer is provided, and a feed pin for connecting a feed line provided on the back surface of the circuit board 16 to a feed point is inserted into the through hole. In the present embodiment, a single-point feeding type circularly polarized patch antenna is used as the GPS antenna 20, but a two-point feeding type patch antenna may be used. Since the GPS antenna 20 is a known patch antenna, detailed description thereof will be omitted.

The TEL antenna 22 has an antenna element 42 obtained by punching a conductor plate into a predetermined shape and bending it. The antenna element 42 is provided at a predetermined height position above the circuit board 16. A feeding portion 44 extends downward from the distal end of the antenna element 42, and the feeding portion 44 is connected to the circuit board 16. More specifically, the antenna element 42 includes a 1 st extending portion 46 extending rearward above the circuit board 16, and a 2 nd extending portion 48 extending forward and continuing to be folded back from a distal end of the 1 st extending portion 46. The tip of the 2 nd extending portion 48 serves as an open portion 50.

As shown in the drawing, the antenna element 42 has an inward-rolled shape in plan view, and the open portion 50 is located farther from the center line L than the 1 st extending portion 46. That is, the antenna element 42 has a shape in which the tip thereof is distant from the ETC antenna 18. The antenna element 32 is located forward relative to the antenna element 42. With such a configuration, the radiation area of the ETC antenna 18 and the radiation area of the TEL antenna 22 are less likely to interfere with each other. The details will be described later.

As shown in fig. 2 (B), a shield case 52 is provided on the back surface of the circuit board 16 so as to cover the center in the width direction thereof in a front-back manner. An amplifier circuit (not shown) of the GPS antenna 20 is provided on the back surface of the circuit board 16 at a position inside the shield case 52. These Amplifier circuits are LNAs (Low Noise amplifiers), and constitute parts of the respective feeder lines (not shown).

The shield case 52 is made of metal and blocks unnecessary radiation from the amplifier circuit. The shield case 52 also functions as a ground region for grounding the antennas. Several places of the bottom surface of the shield case 52 are cut and erected to form conductive pieces 54 having elasticity. The grounding structure formed by these members will be described in detail later.

Through holes 56 are provided in the circuit board 16 at positions on both the right and left sides of the shield case 52. The power feeding portion 44 of the TEL antenna 22 penetrates the through hole 56 and is exposed to the back surface side of the circuit board 16. The power supply portion 44 is soldered to a power supply line (not shown) mounted on the rear surface of the circuit board 16. The feeder line of each antenna is provided as a microstrip line on the back surface of the circuit board 16, and is connected to each feeder port of the connector 24.

Fig. 3 is a central longitudinal sectional view showing the internal structure of the antenna device 1, and shows a section including the center line L shown in fig. 2.

A support base 60 is provided in front of the circuit board 16. The support table 60 supports the ETC antenna 18 from below. The support base 60 is made of an insulator such as resin, and is fixed to the circuit board 16. The support base 60 has an inclined surface 61. A plurality of

support portions

64 and 66 having different heights are projected from the inclined surface 61. The height of support portion 64 is less than the height of support portion 66.

In the present embodiment, 3 support portions 64 are provided, and the ground element 34 is supported from below at 3 points by the 3 support portions 64. Further, 3 support portions 66 are provided, and the antenna element 32 is supported from below at 3 points by the 3 support portions 66. Each support portion 66 penetrates the ground element 34.

In this way, the antenna element 32 and the ground element 34 are supported by the plurality of support portions, and an air gap is formed between the two elements, thereby forming a patch antenna. This ensures the size of each element, and reduces dielectric loss, thereby improving the gain of the ETC antenna 18.

The inclination angle of the antenna element 32 and the ground element 34 is equal to the angle of the inclined surface 61 with respect to the circuit board 16, and is about 23 degrees in the present embodiment. The number and arrangement of the support portions can be arbitrarily selected to maintain the characteristics of the antenna. The connector 24 is provided in the vicinity of the power supply portion 36.

The ground region 17 of the circuit board 16 is connected to the shield case 52. By fastening the substrate 12 and the cover 14, the plurality of conductive pieces 54 come into contact with the substrate 12, and the shield case 52 and the substrate 12 are electrically connected.

Fig. 4 is a diagram showing the structure of the ETC antenna 18 and its periphery in detail. Fig. 4 a is a perspective view showing an assembly of the antenna unit 10 and the substrate 12 (hereinafter also referred to as "antenna base unit 13").

Fig. 4 (B) is a front view showing the ETC antenna 18 and its periphery. Fig. 4 (C) is a sectional view taken along line a-a of fig. 4 (B).

As shown in fig. 4 (a), the substrate 12 is much larger than the circuit substrate 16. Therefore, a sufficient ground area can be secured for the entire antenna base unit 13.

As shown in fig. 4 (B), the two ground connection portions 40 are disposed at positions symmetrical with respect to the power supply portion 36. In the present embodiment, these ground connection portions 40 have a shape symmetrical with respect to the center line of the power supply portion 36. The ground connection portion 40 and the power supply portion 36 extend parallel to each other and are connected perpendicularly to the circuit substrate 16. In the modification, at least one of the ground connection portion 40 and the power supply portion 36 may be disposed to be inclined with respect to the circuit board 16.

The ground connection portion 40 is thicker (larger in cross section) than the power supply portion 36. The distance between the power supply portion 36 and the ground connection portion 40 is smaller than the distance between the side end of the ground element 34 and the ground connection portion 40. That is, the pair of ground connection portions 40 are provided near the center of the ground element 34 and near the power supply portion 36. In other words, a predetermined gap Δ h is formed between the ground element 34 and the ground region 17 on both sides of the ground connection portion 40 (a portion on the opposite side from the power feeding portion 36). The width of the ground connection portion 40 is larger than the gap Δ h.

As shown in fig. 4 (C), the ground element 34 is longer than the antenna element 32 in the front-rear direction. The grounding element 34 is obtained by bending a rectangular conductive plate at a plurality of positions in the longitudinal direction. The ground element 34 has a 1 st surface 70 parallel to the antenna element 32, a 2 nd surface 72 provided at the rear end portion, and a 3 rd surface 74 provided at the front end portion. The 2 nd surface 72 is disposed in communication with the rear end of the 1 st surface 70, forming a slight upward angle with respect to the 1 st surface 70. That is, the 2 nd surface 72 is inclined forward than the 1 st surface 70. The 3 rd surface 74 is provided continuously with the front end of the 1 st surface 70 and extends parallel to the circuit board 16. The ground connection portion 40 is provided in connection with the front end of the 3 rd surface 74. The length of the 2 nd surface 72 and the 3 rd surface 74 in the front-rear direction is very small compared to the 1 st surface 70. By adjusting the length and angle of the 2 nd surface 72, the directivity (radiation pattern of radio waves) of the ETC antenna 18 can be adjusted.

Next, the results of analyzing the characteristics of the ETC antenna 18 will be described.

Fig. 5 is a diagram showing a radiation pattern of a radio wave. Fig. 5 a shows a radiation pattern of the antenna element 32 (see fig. 4B) according to the present embodiment, and fig. 5B shows a radiation pattern of the antenna element of comparative example 1. In comparative example 1, the ground connection portion 40 in the present embodiment is omitted. The upper graph of each graph is a graph showing the directivity (gain) of the radiation pattern in three dimensions, and the lower graph is a graph showing the directivity (gain) of the radiation pattern in two dimensions. The upper side (0 degree in the lower panel) of each figure corresponds to the vehicle front, and the lower side (180 degrees in the lower panel) corresponds to the vehicle rear.

In the present embodiment, a radiation pattern with good left-right balance is obtained toward the front obliquely upward (fig. 5 (a)). In contrast, in comparative example 1, no peak was obtained obliquely upward in the front direction (fig. 5 (B)). That is, according to the present embodiment, the ground region 17 of the circuit board 16 is connected to the ground element 34, so that the ETC antenna 18 (patch antenna) has good directivity (radiation pattern of radio waves).

Fig. 6 and 7 are graphs showing the effect of the position of the ETC antenna on the radiation pattern. In the following explanation, the GPS antenna 20 is omitted for convenience. Fig. 6 shows a case where a TEL antenna is provided. Fig. 6 (a) shows a case where the ETC antenna is disposed at a position forward relative to the TEL antenna (this embodiment). Fig. 6 (B) shows a case where the ETC antenna is disposed relatively rearward of the TEL antenna (comparative example 2).

On the other hand, fig. 7 shows a case where the TEL antenna is not provided. Fig. 7 (a) shows a case where the ETC antenna is disposed at a position forward relative to the TEL antenna (comparative example 3). Fig. 7 (B) shows a case where the ETC antenna is disposed relatively rearward of the TEL antenna (comparative example 4). The upper layer of each figure shows the arrangement structure of the antenna, and the lower layer shows the analysis result of the radiation pattern of the ETC antenna.

According to the analysis result, when the TEL antenna is provided, the radiation pattern of the ETC antenna in comparative example 2 is distorted (deteriorated) (fig. 6 (B)), and a favorable radiation pattern is obtained in the present embodiment (fig. 6 (a)). In the case where the TEL antenna is not provided, radiation patterns having good shapes can be obtained in both comparative example 3 in which the ETC antenna is provided in the front and comparative example 4 in which the ETC antenna is provided in the rear (fig. 7 (a) and 7 (B)).

When comparative example 2 and comparative example 4 were compared (fig. 6 (B), fig. 7 (B)), comparative example 4 could obtain a good radiation pattern. It is thus clear that the presence of the TEL antenna has an influence on the radiation pattern of the ETC antenna. It is considered that the presence of the TEL antenna in the radio wave radiation direction (so-called field of view) of the ETC antenna causes deterioration of the radiation pattern.

In this regard, when comparing the present embodiment with comparative example 3 (fig. 6 (a) and fig. 7 (a)), although the TEL antenna is present in the present embodiment, a good radiation pattern can be obtained to the same extent as in comparative example 3 which does not have the TEL antenna. It is considered that since the TEL antenna is not present in the radio wave radiation direction (field of view) of the ETC antenna, the radiation pattern can be prevented from deteriorating. That is, according to the present embodiment, the radiation pattern can be maintained in a good state by disposing the ETC antenna 18 at a position forward relative to the TEL antenna 22.

Fig. 8 is a diagram showing the influence of the shape of the TEL antenna on the radiation pattern. Fig. 8 a shows a case where the antenna element of the TEL antenna is formed in an inward-winding shape (this embodiment). Fig. 8B shows a case where the antenna element of the TEL antenna is formed into a wraparound shape (comparative example 5). Here, the "inward-winding shape" means a winding shape in which the antenna element starts to be wound at a position closer to the inside of the circuit board, and the tip (open portion) of the antenna element is separated from the ETC antenna. On the other hand, the "outward winding shape" means a winding shape in which the antenna element starts to be wound at a position on the outer side of the circuit board and the tip (open portion) of the antenna element comes close to the ETC antenna. The upper layer of each figure shows the arrangement structure of the antenna, and the lower layer shows the radiation pattern of the ETC antenna.

According to the analysis results, the present embodiment using the inner wrap shape can obtain a favorable radiation pattern compared to comparative example 5 using the outer wrap shape. When the antenna element 23 is wound as in comparative example 5, the currents of the ETC antenna 18 are easily coupled, and a strong current distribution is easily formed. As a result, it is considered that unnecessary radiation is likely to be generated, and the radiation pattern is likely to be deteriorated. In this regard, since the antenna element 22 is formed to be turned inside in the present embodiment, the radiation pattern can be maintained well.

That is, in the present embodiment, the "field of view area" is secured by disposing the ETC antenna 18 at a position relatively forward of the TEL antenna 22, and the positions where the current distribution is strong in each of the two antennas are prevented from approaching each other by making the antenna elements of the TEL antenna 22 involuted. This can maintain a favorable radiation pattern for each radio wave.

As described above, in the present embodiment, the ground element 34 is disposed on the circuit board 16 in an inclined manner with respect to the ETC antenna 18, the antenna element 32 extends substantially in parallel with the ground element 34, and the ground element 34 is connected to the ground region 17, thereby ensuring directivity. The antenna element 32 and the ground element 34 are both arranged such that their tips are close to the circuit board 16. In particular, the feeding portion 36 extends from the distal end of the antenna element 32 and is connected to a feeding line of the circuit board 16.

Therefore, according to the present embodiment, the feeding portion 36 can be shortened as compared with the conventional structure in which the antenna element and the circuit board are connected by the coaxial cable, and the transmission loss of the radio wave can be suppressed. It is known that, in general, the higher the frequency of the radio wave, the greater such transmission loss. In this regard, in the circuit board 16 of the present embodiment, the ETC antenna 18 having a relatively high frequency is disposed in front of the GPS antenna 20 having a relatively low frequency, and the power feeding unit 36 is disposed in the vicinity of the connector 24. This further contributes to suppression of transmission loss.

The ground connection portion 40 extends from the front end of the ground element 34 and is connected to the ground region 17 of the circuit board 16. This can shorten the ground connection portion 40, and thus, it is easy to ensure symmetry of the entire ground element 34. As a result, excellent directivity can be obtained.

More specifically, since the pair of ground connection portions 40 are disposed with the power supply portion 36 interposed therebetween, it is easy to ensure symmetry of the left and right ground lines. In particular, the ground connection portions 40 are arranged at positions symmetrical with respect to the power supply portion 36, which contributes to securing the symmetry. As a result, it was also found from the analysis results that a favorable radiation pattern could be obtained. That is, according to the present embodiment, the antenna device 1 including the patch antenna can improve the directivity thereof.

Since the feeding portion 36 is a part of the antenna element 32 and the ground connection portion 40 is a part of the ground element 34, the antenna element 32 and the ground element 34 are directly connected to the circuit board 16. Therefore, according to the present embodiment, the number of components can be reduced and an advantage in cost can be obtained as compared with a conventional structure in which an antenna element and a circuit board are connected by a coaxial cable.

In the present embodiment, the radiation pattern of the radio wave of the ETC antenna 18 can be maintained well by disposing the ETC antenna 18 at a position forward relative to the TEL antenna 22. In other words, the radiation pattern of the ETC antenna 18 is not easily affected by the TEL antenna 22, and the electrical characteristics thereof are easily and stably maintained. Therefore, the following advantages are also provided: for example, even if it is necessary to perform shape adjustment or the like in order to change the corresponding frequency to the TEL antenna 22, the processing is easy.

While the preferred embodiments of the present invention have been described above, it goes without saying that the present invention is not limited to the specific embodiments, and various modifications are possible within the scope of the technical idea of the present invention.

In the above embodiment, the example in which the feeding portion 36 is integrally formed with the antenna element 32 is shown, but the feeding portion 36 may be formed by a wire. Further, although the example in which the ground connection portion 40 is integrally formed with the ground element 34 is shown, the ground connection portion 40 may be formed by wiring. Since the antenna element 32 and the ground element 34 are both arranged such that the tips thereof are close to the surface of the circuit board 16, the wiring is short. With this configuration, good gain performance can be expected.

In the above-described embodiment, the antenna device 1 is provided with the GPS antenna 20 and the TEL antenna 22 having different directivities from the ETC antenna 18. In a modification, either one or both of the GPS antenna 20 and the TEL antenna 22 may be omitted. Or other antennas may be configured instead of either or both of them. In addition to these two antennas, other antennas may be provided.

In the above embodiment, the following configuration is shown: the circuit board 16 has a ground region 17 on the front surface thereof, a power supply line on the rear surface thereof, and a through hole 38 penetrating the front and rear surfaces. The feeding portion 36 of the antenna element 32 is connected to the feeding line on the rear surface through the through hole 38. In the modification, at least a part of the feed line may be provided on the surface of the circuit board 16 to connect to the feed portion 36. In this case, the through hole 38 is not required. The ground regions 17 may be formed on both sides of the power supply line.

In the above embodiment, the following example is shown: since the antenna element 32 and the ground element 34 are substantially symmetrical with respect to their center lines, the feeding portion 36 and the ground connection portion 40 are arranged symmetrically with respect to their center lines. When either one of the antenna element 32 and the ground element 34 has an asymmetric shape with respect to the center line, the arrangement of the feeding portion 36 and the ground connection portion 40 may be asymmetric with respect to the center line in accordance with the asymmetric shape, and the balance of the radiation pattern may be adjusted.

In the above embodiment, an example is shown in which: the substrate 12 is made of a conductive material, and the substrate 12 is connected to the ground region 17 to form a ground region (i.e., a ground plate). In the modification, the substrate 12 and the ground region 17 may not be electrically connected, but may be configured as only a cover. Alternatively, a cover may be separately provided, and the antenna unit 10 and the substrate 12 (ground plate) may be housed between the cover and the lid 14. In this case, the substrate 12 is preferably made larger than the ground region 17 of the circuit substrate 16, but the shape and size of the substrate 12 can be appropriately selected. Alternatively, the circuit board 16 may be made larger to function also as a lid, and the substrate 12 may be omitted.

The gain performance of the ETC antenna 18 can be adjusted by the position and width (thickness) of the ground connection portion 40 at the distal end of the ground element 34, and therefore, the position and width can be appropriately set, which is not described in the above embodiment.

In the above embodiment, the connector 24 is disposed on the circuit board 16 and the feeder line is connected thereto. In a modification, a cable such as a pigtail (pigtail) may be provided instead of the connector.

In the above-described embodiment, an example is shown in which the field of view of the ETC antenna 18 is secured by disposing the ETC antenna 18 at a position relatively forward of the TEL antenna 22 (see fig. 2 and the like). In a modification, the height of the antenna element 42 may be adjusted (e.g., lowered) to secure the field of view of the ETC antenna 18.

In the above embodiment, the front half of the ETC antenna 18 is disposed forward of the TEL antenna 22, but the whole of the ETC antenna 18 may be disposed forward of the TEL antenna 22. At least a part of the ETC antenna 18 may be arranged in front of the TEL antenna 22 to secure a field of view of the ETC antenna 18.

In the above-described embodiments, the patch antenna (ETC antenna 18) is provided on the circuit board, and the ground element is connected to the ground region of the circuit board. In a modification, a conductive plate such as a metal plate or a conductive resin plate may be used as a "substrate" to connect the ground element thereto. That is, the "substrate having a ground region" may be a circuit substrate or a conductor plate on which no circuit is mounted. It goes without saying that the "substrate" may have a structure in which one or both of the front surface and the back surface have a concave-convex shape.

In the above embodiment, the antenna element is made of metal, but may be made of other conductive materials such as conductive resin.

In the above embodiment, the case where the antenna device is provided on the instrument panel has been described, but the antenna device may be provided at another position of the vehicle body. The antenna device may be provided in a ship or other moving system.

The present invention is not limited to the above-described embodiments and modifications, and can be embodied by modifying the components without departing from the scope of the invention. Various inventions may be formed by appropriately combining a plurality of constituent elements disclosed in the above embodiments and modifications. Further, some of the components may be deleted from all the components shown in the above embodiments and modifications.

Claims

1. An antenna device, characterized in that,

the antenna device includes:

a substrate having a ground region; and

a patch antenna disposed on the substrate,

the patch antenna includes:

a ground element disposed to be inclined with respect to the substrate so that a front end side thereof is close to the substrate and a rear end side thereof is distant from the substrate;

an antenna element extending substantially parallel to the ground element;

a feeding portion extending from a distal end of the antenna element; and

and a ground connection portion extending from a front end of the ground element and connected to the ground region.

2. The antenna device of claim 1,

the power supply unit is provided with one, and two ground connection units are arranged so as to sandwich the power supply unit.

3. The antenna device according to claim 2,

the two ground connection portions are disposed at positions symmetrical with respect to the power supply portion.

4. The antenna device according to any of claims 1-3,

the antenna element and the ground element are each a square conductor plate.

5. The antenna device according to any of claims 1 to 4,

the ground connection portion is thicker than the power supply portion.

6. The antenna device according to any of claims 1 to 5,

the ground element is longer than the antenna element in the front-rear direction,

the ground element has a 1 st face parallel to the antenna element and a 2 nd face forming an angle with respect to the 1 st face.

7. The antenna device according to claim 6,

the 2 nd surface is provided at a rear end portion of the ground element.

8. The antenna device according to claim 6 or 7,

the ground element has a surface parallel to the substrate on a front end side.

9. The antenna device according to any one of claims 1 to 8,

the substrate is a circuit substrate, and the substrate is a circuit substrate,

an antenna element for a telephone is provided on the circuit board,

the antenna element is located at a position relatively forward of the telephone antenna element.

10. The antenna device according to claim 9,

the telephone antenna element has a 1 st extension part extending rearward at a predetermined height position above the circuit board, and a 2 nd extension part extending forward continuously from the 1 st extension part,

the top end of the 2 nd extending part is provided with an open part,

the open portion is farther from the antenna element than the 1 st extension portion.

11. The antenna device according to any one of claims 1 to 10,

the substrate is a circuit substrate and is provided with

1 st patch antenna as the patch antenna, and

a 2 nd patch antenna parallel to the circuit substrate,

the frequency band of the 1 st patch antenna is higher than that of the 2 nd patch antenna,

the 1 st patch antenna is disposed on the front side of the 2 nd patch antenna.

12. The antenna device of claim 11,

and a connector for connecting the feed line of the 1 st patch antenna and the feed line of the 2 nd patch antenna is provided in the vicinity of the feed portion.