Antenna device and vehicle antenna system

Abstract

To provide an antenna device with a simple structure.SOLUTION: An antenna device comprises: a first conductor plate that includes a first end part and a second end part opposite to the first end part, and into which a power supply part is provided near from the second end part; a second conductor plate that includes a third end part connected to the power supply part, a fourth end part positioned at a part separated from the first conductor plate, and a plate surface expanded a width in a direction parallel to the first conductor plate as being directed from the third end part to the fourth end part; and a third conductor plate that is connected to the fourth end part and is faced to the first conductor plate. The third conductor plate includes a fifth end part that is an open end opposite to the fourth end part.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to an antenna device and a vehicle antenna system. [Background technology]

[0002] Conventionally, antenna devices suitable for transmitting and receiving relatively high frequency radio waves in the UHF (Ultra High Frequency) band of 300 MHz to 3 GHz or the SHF (Super High Frequency) band of 3 GHz to 30 GHz are known (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2019 / 151407 Summary of the Invention [Problem to be solved by the invention]

[0004] The antenna device disclosed in Patent Document 1 includes a first conductor plate on which a power feed section is provided, a second conductor plate connected to the power feed section, and a third conductor plate capacitively coupled to an end of the second conductor plate. However, this antenna device has a relatively complicated structure in which the third conductor plate capacitively coupled to the second conductor plate is connected to the first conductor plate.

[0005] The present disclosure provides an antenna device and a vehicle antenna system with a simple structure. [Means for solving the problem]

[0006] The present disclosure provides: a first conductor plate having a first end and a second end opposite to the first end, the first conductor plate having a power supply portion provided near the second end; a second conductor plate having a third end connected to the power supply portion, a fourth end located at a position away from the first conductor plate, and a plate surface whose width in a direction parallel to the first conductor plate increases from the third end toward the fourth end; a third conductor plate connected to the fourth end portion and facing the first conductor plate, The third conductive plate has a fifth end which is an open end opposite to the fourth end, and an antenna device and a vehicle antenna system including the antenna device are provided. [Effects of the Invention]

[0007] According to the present disclosure, an antenna device and a vehicle antenna system having a simple structure can be provided. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a perspective view showing a configuration example of an antenna device according to an embodiment of the present invention; [Figure 2] 1 is an exploded perspective view showing an example of the configuration of an antenna device according to an embodiment of the present invention; [Figure 3] 3 is an exploded perspective view showing an example of the configuration of the antenna device of the present embodiment from a different viewpoint than that shown in FIG. 2. FIG. [Figure 4] 1 is a side view showing an example of a configuration of an antenna device according to an embodiment of the present invention; [Figure 5] FIG. 2 is a circuit diagram showing the connection relationship between an antenna, a feed line, and a matching circuit. [Figure 6] 1 is a diagram showing an example of the configuration of a vehicle antenna system including an antenna device according to an embodiment of the present invention; [Figure 7] 5 is a diagram showing an example of a measurement result of the VSWR (voltage standing wave ratio) of the antenna device of the present embodiment. FIG. [Figure 8] 10A and 10B are diagrams illustrating an example of measurement results of the antenna gain of the antenna device of the present embodiment. [Figure 9] 10A and 10B are diagrams illustrating an example of measurement results of the directivity of the antenna device according to the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments will be described with reference to the drawings. Note that for ease of understanding, the scale of each part in the drawings may differ from the actual scale. Directions such as parallel, right-angled, orthogonal, horizontal, vertical, up-down, left-right, and so on are permissible to the extent that they do not impair the functions and effects of the embodiments. The X-axis, Y-axis, and Z-axis directions represent directions parallel to the X-axis, Y-axis, and Z-axis, respectively. The X-axis, Y-axis, and Z-axis directions are mutually orthogonal. The XY plane, YZ plane, and ZX plane represent imaginary planes parallel to the X-axis and Y-axis directions, imaginary planes parallel to the Y-axis and Z-axis directions, and imaginary planes parallel to the Z-axis and X-axis directions, respectively.

[0010] Fig. 1 is a perspective view showing one configuration of an antenna device of this embodiment. The antenna device 101 shown in Fig. 1 is an example of a vehicle antenna device. The antenna device 101 includes a rectangular parallelepiped housing 60 that stores internal components, and a bracket 63 for mounting the antenna device 101 to a vehicle. The housing 60 includes a housing 61 that houses the internal components, and a cover 62 that closes an opening of the housing 61. The housing 60 (more specifically, the housing 61 and the cover 62) is formed of a dielectric material such as resin.

[0011] Antenna device 101 is used in a state mounted on a vehicle, and may be disposed inside or outside the vehicle. For example, when antenna device 101 is disposed inside the vehicle, it is preferable that the surface of cover 62 is attached to the vehicle by bracket 63 so that it faces the outside of the vehicle (in this example, when the XY plane is the horizontal plane, the negative side in the Y-axis direction) so that it does not face a conductor such as a metal body via a dielectric such as a window glass.

[0012] At least one antenna device 101 is attached to, for example, a vehicle window glass or its vicinity. Examples of vehicle window glass include a rear window attached to the rear of the vehicle, a windshield attached to the front of the vehicle, a side window attached to the side of the vehicle, and a roof glass attached to the roof of the vehicle. Vehicle window glass is not limited to these examples.

[0013] Specific examples of the location near the window glass where the antenna device 101 may be attached include locations on the vehicle side away from the window glass, such as the roof, console, pillar, garnish, mirror, etc. The antenna device 101 may also be attached to the front grille, hood, trunk, door, spoiler, shark fin, etc.

[0014] The housing 60 and the bracket 63 are merely examples, and their configurations may be changed as appropriate depending on the location where they are installed.

[0015] Fig. 2 is an exploded perspective view showing an example of the configuration of the antenna device of this embodiment. Fig. 3 is an exploded perspective view showing an example of the configuration of the antenna device of this embodiment from a different perspective than Fig. 2. Antenna device 101 includes conductor plate 10, conductor plate 20, and conductor plate 30 as internal components.

[0016] Conductive plate 10 is an example of a first conductive plate. Conductive plate 10 has end 13 and end 14 opposite end 13. End 13 is an example of a first end. End 14 is an example of a second end. In this example, end 13 and end 14 are opposite edges in the X-axis direction and extend along the Y-axis direction.

[0017] The conductor plate 10 is, for example, a flat plate having a conductor layer 18 (see FIG. 2) and a conductor layer 16 (see FIG. 3). In the example shown in FIGS. 2 and 3, the conductor plate 10 is a substrate having a dielectric layer 15, a conductor layer 18 formed on one surface 12 of the dielectric layer 15, and a conductor layer 16 formed on the other surface 11 of the dielectric layer 15. A signal line 17 is formed on the surface 11. The signal line 17 is a strip conductor formed with a gap between the two conductor layers 16. The conductor layers 16 and 18 are conductively connected to each other, for example, via a plurality of through holes formed in the dielectric layer 15. The signal line 17 may be formed on the surface 12 of the conductor plate 10.

[0018] A power supply unit 3 is provided near end 14, with conductor layers 18 and 16 serving as ground references. Power supply unit 3 is a feeding point that supplies power to conductor plates 20 and 30, which function as a planar inverted-L antenna of antenna device 101. Power supply unit 3 is located between end 13 and end 14 and closer to end 14. For example, power supply unit 3 is a land (electrode) formed on surface 11. When the length of conductor plate 10 in the X-axis direction is taken as 100%, the vicinity of end 14 may be within a range of 80% or more from end (edge) 13, preferably within a range of 90% or more, more preferably within a range of 95% or more, and even more preferably within a range of 97% or more. By arranging power supply unit 3 near end 14, antenna device 101 itself can be made compact.

[0019] In this example, the conductor plate 10 is provided with a feed line 5 connected to the feed unit 3, and the feed line 5 faces the conductor plate 30. The feed line 5 is a transmission line having one end connected to the feed unit 3. Specific examples of the feed line 5 include a microstrip line, a strip line, a coplanar waveguide, a coplanar strip, a slot line, and a waveguide. The feed line 5 shown in FIGS. 2 and 3 is a CPWG (coplanar waveguide with ground plane) in which a conductor layer 18 is formed as a ground plane on a surface 12 opposite to a surface 11 on which the conductor layer 16 and the signal line 17 are formed.

[0020] Conductive plate 20 is an example of a second conductive plate. Conductive plate 20 has end 23 connected to power supply unit 3 and end 24 located at a position away from conductive plate 10. End 23 is an example of a third end. End 24 is an example of a fourth end. End 24 is located on the opposite side of end 23, more specifically, on the opposite side of end 23 from the side on which conductive plate 10 is located. End 23 and end 24 are located at a distance from each other in the Z-axis direction.

[0021] The conductive plate 20 has a plate surface 21 whose width in a direction parallel to the conductive plate 10 (the Y-axis direction in the illustrated example) increases from the end 23 to the end 24. Here, the direction parallel to the conductive plate 10 may be the X-axis direction, but preferably is a direction inclined within a range of less than ±90° with respect to the Y-axis direction. In particular, the direction parallel to the conductive plate 10 is preferably in a range of ±45° with respect to the Y-axis direction, more preferably in a range of ±20°, even more preferably in a range of ±5°, and most preferably coincident with the Y-axis direction. Furthermore, "the conductive plate 20 increases in width from the end 23 to the end 24" means that there is a portion where the width increases from the end 23 to the end 24. For example, there may be a portion where the width remains constant or a portion where the width decreases from the end 23 to the end 24. It is preferable that the conductive plate 20 does not have a portion where the width decreases from the end 23 to the end 24.

[0022] Conductive plate 20 in this embodiment has plate surface 21 that includes both end 23 and end 24 on the YZ plane. Conductive plate 20 may have a flat shape without bending as shown in the figure, or may have a three-dimensional shape with a bent portion. Providing bent plate surface 21 enables antenna device 101 to be made lower in height than an unbent form. Here, "lower in height" corresponds to shortening the distance (height) in the Z-axis direction relative to conductive plate 10.

[0023] Conductive plate 30 is an example of a third conductive plate. Conductive plate 30 is connected to end portion 24 and faces conductive plate 10. In this example, conductive plate 30 has plate surface 32 facing surface 11 of conductive plate 10 in the Z-axis direction, and end portion 35, which is an open end opposite end portion 24. End portion 35 is an example of a fifth end portion. End portion 35 is, for example, an edge facing end portion 24 in the X-axis direction, and extends along the Y-axis direction.

[0024] The antenna device 101 of this embodiment transmits and receives radio waves using a relatively simple planar inverted-L antenna formed by conductor plates 20 and 30. "Transmitting and receiving" refers to either or both of transmission and reception. Because the antenna device 101 has a relatively simple structure equipped with such a planar inverted-L antenna, the manufacturing method of the antenna device 101 can be simplified, improving productivity.

[0025] Furthermore, antenna device 101 uses conductor layer 18 and conductor layer 16 provided on conductor plate 10 as a ground plane for the planar inverted-L antenna. This allows antenna device 101 to obtain stable antenna characteristics even when placed close to a metal or resin part of a vehicle, and makes it easy to ensure isolation from other antennas.

[0026] Furthermore, since the planar inverted-L antenna is literally planar, antenna device 101 (planar inverted-L antenna) has a wider bandwidth than a linear inverted-L antenna. Furthermore, in antenna device 101, conductor plate 20 is connected at end 23 to power feeder 3, which uses the conductor layer of conductor plate 10 as a ground reference, and plate surface 21 is formed so that the width increases with increasing distance from conductor plate 10. Therefore, by setting the length of the outer edge portion of plate surface 21 (for example, the curved portion expanding from end 23) so that the planar inverted-L antenna has an electrical length that allows it to operate in a desired frequency range, the planar inverted-L antenna can also function as a WB (Wide Band) antenna.

[0027] The conductor length from the power supply part 3 or the end 23 to the end 35 is L2, the wavelength shortening rate of the surrounding medium of the conductor plate 20 and the conductor plate 30 is k2, and the wavelength in the air of the transmitted and received radio wave is λ. L2 / k2<λ / 4...Equation 1 In this case, the planar inverted L antenna formed by the conductive plates 20 and 30 can be made smaller than a typical λ / 4 monopole antenna, which is advantageous for making the antenna device 101 smaller.

[0028] The conductor length L2 corresponds to the sum of the shortest path length along the conductor plate 20 from the power supply part 3 or end 23 to end 24 and the shortest path length along the conductor plate 30 from end 24 to end 35.

[0029] Furthermore, when the antenna device 101 satisfies formula 1, the planar inverted-L antenna has an electrical length shorter than k2 × λ / 4, and therefore has capacitive impedance. Therefore, it may be difficult to achieve impedance matching with the coaxial cable 4 (see FIG. 3) electrically connected to the feed line 5. In such cases, it is preferable to connect a matching circuit 40 that matches the impedance between the planar inverted-L antenna and the coaxial cable 4 to the feed line 5. Connecting the matching circuit 40 to the feed line 5 can expand or shift the frequency band that the planar inverted-L antenna can match.

[0030] Also, the length of the feed line 5 is L1, the wavelength shortening rate of the dielectric layer 15 is k1, the conductor length from the feeder 3 or end 23 to end 35 is L2, the wavelength shortening rate of the surrounding medium of the conductor plate 20 and the conductor plate 30 is k2, and the wavelength in the air of the radio wave to be transmitted and received is λ. λ / 4 ≦ (L1 / k1)+(L2 / k2) ≦ λ / 2 ··· Formula 2 In this case, the combination of the feed line 5 and the planar inverted-L antenna has an inductive impedance. In this case, connecting a matching circuit 40 having a capacitive impedance to the feed line 5 makes it easier to achieve impedance matching. When the planar inverted-L antenna formed by the conductor plates 20 and 30 is used as the inverted-L antenna 2 (see FIG. 5), the matching circuit 40 having a capacitive impedance has a capacitor connected between the feed line 5 and the ground, as shown in FIG. 5, for example. In the example shown in FIG. 3, the matching circuit 40 has a capacitor connected between the signal line 17 and the conductor layer 16.

[0031] The length L1 corresponds to the physical line length of the signal line 17 from the input end of the feed line 5 (the line end opposite the feed unit 3) to the end of the feed line 5 (the feed unit 3).

[0032] For example, in the case of a single conductor plate 10 on which the feed line 5 is formed, the length L1 is adjusted to a length (e.g., a length shorter than k1 × λ / 4) such that the end of the feed line 5 (the feed unit 3) is nearly short-circuited when a high-frequency signal with a wavelength λ is input to the input end of the feed line 5. In this case, when a planar inverted-L antenna satisfying Equation 1 is connected to the feed unit 3, the combination of the feed line 5 and the planar inverted-L antenna behaves as an antenna with an inductive impedance satisfying Equation 2 when viewed from the input end of the feed line 5. In this case, connecting a matching circuit 40 with a capacitive impedance to the feed line 5 makes it easier to achieve impedance matching. Furthermore, if the impedance-matching frequency deviates from the desired value due to the enclosure of the dielectric casing 60 (more specifically, the housing 61 and the cover 62), providing the matching circuit 40 can suppress the deviation. The length L1 may be 60% to 140% of k1×λ / 4 as a length that allows matching, and may be 60% to 100% of k1×λ / 4 as a length that allows miniaturization.

[0033] 4 is a side view showing an example of the configuration of the antenna device of this embodiment. The conductor length (along the Z-axis) from the power supply 3 or end 23 to the end 24 is H, and the conductor length (along the Y-axis) from the power supply 3 or end 23 to the end where the width of the plate surface 21 (along the Y-axis) gradually increases toward the end 24 and becomes constant is H. P In this case, H / 3 ≦ H P ≦ 2×H / 3...Equation 3 In this case, the band of the planar inverted-L antenna can be broadened, and the conductor plate 20 can be easily connected to the power supply portion 3. In terms of the broadening of the band of the planar inverted-L antenna and the ease of connecting the conductor plate 20 and the power supply portion 3, H P may be 5×H / 12 or more, or 7×H / 12 or less. In addition, when viewed in a plan view on the YZ plane, conductive plate 20 may have a shape that is symmetrical with respect to an imaginary line that passes through power supply unit 3 or end portion 23 and is parallel to the Z axis (the shortest path length along conductive plate 20 from power supply unit 3 or end portion 23 to end portion 24).

[0034] Furthermore, if the width in the short side direction of the conductor plate 30 (width d6 in FIG. 2) is 60% or more of the width in the short side direction of the conductor plate 10 (width d4 in FIG. 2), impedance matching is easily achieved even if the conductor length L2 from the power supply portion 3 or end 23 to end 35 is relatively short. In terms of facilitating impedance matching, the width in the short side direction of the conductor plate 30 is preferably 70% or more, and more preferably 80% or more, of the width in the short side direction of the conductor plate 10. In terms of miniaturizing the antenna device 101, the width in the short side direction of the conductor plate 30 is preferably 110% or less, and more preferably 100% or less, of the width in the short side direction of the conductor plate 10.

[0035] In the example shown in Figure 2, width d6 corresponds to the width parallel to end 24 of conductor plate 20 or the width parallel to end 35 of conductor plate 30, and width d4 corresponds to the width parallel to end 14 or end 13 of conductor plate 10.

[0036] Furthermore, the wavelength shortening rate of the medium between conductor plate 10 and conductor plate 30 is k, and the wavelength in the air of the transmitted and received radio waves is λ. In this case, if the distance H (see FIG. 4) between conductor plate 10 and conductor plate 30 is 0.038×λ×k or more and 0.125×λ×k or less, the antenna gain of the planar inverted-L antenna is improved in frequency bands included in the UHF band. From the viewpoint of improving the antenna gain of the planar inverted-L antenna in frequency bands included in the UHF band, the distance H is preferably 0.043×λ×k or more and 0.120×λ×k or less, and more preferably 0.048×λ×k or more and 0.115×λ×k or less.

[0037] Conductor plate 30 is preferably parallel to conductor plate 10 in that the antenna gain of the planar inverted-L antenna is improved in the frequency bands included in the UHF band or SHF band, but does not have to be parallel to conductor plate 10. Furthermore, conductor plate 20 is preferably perpendicular to conductor plates 10 and 30 in that the antenna gain of the planar inverted-L antenna is improved in the frequency bands included in the UHF band or SHF band, but does not have to be perpendicular.

[0038] In a plan view of the conductor plate 30, it is preferable that the end 35 overlaps with the end 13 or is located closer to the end 14 than the end 13, in terms of miniaturizing the planar inverted-L antenna and improving the antenna gain of the planar inverted-L antenna in the frequency bands included in the UHF band or SHF band. However, in a plan view of the conductor plate 30, the end 35 does not have to overlap with the end 13, and may be located on the opposite side of the end 13 from the end 14.

[0039] A connector 50 for connecting the feed unit 3 or the feed line 5 to one end of a coaxial cable 4 outside the antenna device may be provided on the conductor plate 10. This allows one end of the coaxial cable 4 to be easily connected to the feed unit 3 or the feed line 5. At one end of the coaxial cable 4, the inner conductor of the coaxial cable 4 is electrically connected to the input end of the signal line 17 of the feed line 5, and the outer conductor of the coaxial cable 4 is electrically connected to the conductor layer 18 and the conductor layer 16. The other end of the coaxial cable 4 is connected to a receiving device or a communication device. The connector 50 may have a built-in amplifier that amplifies a signal passing between the coaxial cable 4 and the feed line 5. The amplifier that amplifies the signal may be inserted between the connector 50 and the feed line 5 and mounted on at least one of the surfaces 11 and 12 of the conductor plate 10. The amplifier may include a matching circuit 40.

[0040] The planar inverted-L antenna is a planar antenna capable of transmitting and receiving radio waves in a predetermined frequency band. The predetermined frequency band is a relatively high frequency band such as the UHF band or the SHF band. Specific examples of frequency bands included in the UHF band include the band of terrestrial digital television broadcast waves (e.g., 470 MHz to 710 MHz) and the band including 760 MHz for Intelligent Transport Systems (ITS) (e.g., 755 MHz to 765 MHz).

[0041] The planar inverted-L antenna may be impedance-matched to be suitable for transmitting and receiving radio waves in the relatively high frequency band of the UHF (Ultra High Frequency) band and the 600 MHz to 6 GHz frequency band (sub6) used in the fifth-generation communication (5G) standard.

[0042] The planar inverted-L antenna may be impedance-matched to efficiently transmit and receive radio waves of Wi-Fi, a wireless local area network (LAN).The planar inverted-L antenna may be impedance-matched to transmit and receive radio waves in the frequency bands specified by the IEEE802.11a, b, g, n, ac, ah, and ax communication standards (863 MHz to 868 MHz (Europe), 902 MHz to 928 MHz (US), 2400 MHz to 2497 MHz (worldwide), 5150 MHz to 5350 MHz (worldwide), 5470 MHz to 5850 MHz (worldwide), etc.).

[0043] The planar inverted-L antenna may be impedance-matched to transmit and receive radio waves in the 2400 MHz to 2483.5 MHz frequency range used by Bluetooth (registered trademark). The planar inverted-L antenna may be impedance-matched to transmit and receive radio waves in the frequency bands used in vehicle-to-infrastructure (V2I) or vehicle-to-vehicle (V2V) communications of intelligent transport systems (e.g., 755.5 MHz to 764.5 MHz (Japan) specified by ARIB STD-T109, 5850 MHz to 5925 MHz specified by IEEE802.11p). The planar inverted-L antenna may be impedance-matched to transmit and receive radio waves in the frequency bands used by WiMAX (registered trademark), another wireless communication technology (e.g., 2300 MHz to 2400 MHz, 2496 MHz to 2690 MHz, 3400 MHz to 3600 MHz). The planar inverted-L antenna may be impedance-matched so as to transmit and receive radio waves in the low band (3245 MHz to 4742 MHz) of a UWB (ultra-wideband) wireless communication system.

[0044] FIG. 6 is a diagram showing an example of the configuration of a vehicle antenna system including the antenna device of this embodiment. The vehicle antenna system 401 shown in FIG. 6 includes a vehicle window glass 201 and an antenna device 101 attached to the window glass 201 or in the vicinity thereof. FIG. 6 illustrates an example in which the window glass 201 is a windshield and the antenna device 101 is arranged inside the vehicle cabin. The antenna device 101 is arranged near an upper corner of the window glass 201 attached to the window frame of the vehicle 301 so that the conductor plate 10 is parallel to the horizontal plane. The antenna device 101 is connected to a communication device (not shown) via a coaxial cable 4. The antenna device 101 is attached to face the window glass 201 and transmits and receives radio waves to and from the outside of the vehicle through the window glass 201. In this way, the antenna device 101, when arranged on or in the vicinity of the window glass 201, can transmit and receive radio waves to and from the outside of the vehicle with high sensitivity.

[0045] Fig. 7 is a diagram showing an example of the measurement results of the VSWR (voltage standing wave ratio) of the antenna device 101 arranged as shown in Fig. 6. A VSWR of 3.5 or less is preferable, and the closer to 1 the value is, the better the impedance matching is. In the case of the antenna device 101, as shown in Fig. 7, the VSWR is 3.5 or less in the band of 720 MHz to 800 MHz, so that impedance matching was achieved over a relatively wide frequency band.

[0046] Fig. 8 is a diagram showing an example of the measurement results of the antenna gain of antenna device 101 arranged as shown in Fig. 6. The antenna gain at each frequency shown on the vertical axis in Fig. 8 indicates the average value of the antenna gain measured in each direction of 360° in the horizontal plane. In the case of antenna device 101, according to Fig. 8, the antenna gain is approximately -12 dBi or more in the band from 680 MHz to 840 MHz in both the vertically polarized wave and the horizontally polarized wave, so that a high antenna gain was obtained over a relatively wide frequency band.

[0047] Fig. 9 shows an example of the measurement results of antenna gain (directivity) measured in each direction of 360° in a horizontal plane of antenna device 101 arranged as shown in Fig. 6 for frequencies of 755 MHz, 760 MHz, and 765 MHz. Note that when measuring directivity, the Z-axis direction of antenna device 101 in Fig. 2 corresponds to the vertical direction, and the negative Y-axis direction corresponds to the direction parallel to the horizontal plane and pointing toward the outside of the vehicle. Fig. 9 shows the antenna gain (directivity) on the XY plane as viewed from the vertical direction, i.e., the Z-axis direction. At each frequency, a relatively round directivity was obtained for both vertically polarized and horizontally polarized waves.

[0048] 7, 8, and 9, antenna device 101 is suitable for application to an ITS antenna that uses vertically polarized waves of 755 MHz to 765 MHz, for example. However, antenna device 101 is not limited to ITS antennas, and can also be applied to antenna devices that use horizontally polarized waves, antenna devices that use radio waves of both vertically polarized waves and horizontally polarized waves, and antenna devices with a wider bandwidth than ITS antennas with relatively narrowband specifications.

[0049] In Figures 7, 8 and 9, the dimensions of each part when measuring the antenna gain are as follows: d1:24mm d2:58mm d3:19mm d4:16mm d5:55mm d6:16mm H:21mm H P :11mm L1: 44mm These actual dimensions satisfy the above formulas 1, 2 and 3.

[0050] Although the embodiments have been described above, the technology of the present disclosure is not limited to the above-described embodiments, and various modifications and improvements are possible, such as combinations with or substitutions for part or all of other embodiments. [Explanation of symbols]

[0051] 2 Inverted L antenna 3 Power supply unit 4 coaxial cables 5 Power supply line 10 First conductor plate 11,12 surface 13,14 End 15 Dielectric Layer 16,18 Conductor layer 17 Signal line 20 Second conductor plate 21 Board surface 23 Third end 24 4th end 30 Third conductor plate 32 Board surface 35 5th end 40 matching circuit 50 connectors 60 cabinets 61 Housing 62 Cover 63 Bracket 101 Antenna device 201 Window Glass 301 vehicles 401 Vehicle Antenna System

Claims

1. a first conductor plate having a first end and a second end opposite to the first end, the first conductor plate having a power supply portion provided near the second end; a second conductor plate having a third end connected to the power supply portion, a fourth end located at a position distant from the first conductor plate, and a plate surface whose width in a direction parallel to the first conductor plate increases from the third end toward the fourth end; a third conductor plate connected to the fourth end portion and facing the first conductor plate, the third conductor plate has a fifth end that is an open end opposite to the fourth end, the first conductor plate is provided with a power supply line connected to the power supply portion, the first conductive plate includes a dielectric layer; Let L1 be the length of the feed line, k1 be the wavelength shortening rate of the dielectric layer, L2 be the conductor length from the feed section or the third end to the fifth end, k2 be the wavelength shortening rate of the second conductor plate and the third conductor plate's surrounding medium, and λ be the wavelength in the air of the radio wave to be transmitted and received. λ / 4 ≦ (L1 / k1) + (L2 / k2) ≦ λ / 2 Meet the antenna device.

2. A first conductor plate having a first end and a second end opposite the first end, with a power supply section provided near the second end; a second conductor plate having a third end connected to the power supply portion, a fourth end located at a position distant from the first conductor plate, and a plate surface whose width in a direction parallel to the first conductor plate increases from the third end toward the fourth end; a third conductor plate connected to the fourth end portion and facing the first conductor plate, the third conductor plate has a fifth end that is an open end opposite to the fourth end, When the conductor length from the power supply portion or the third end portion to the fourth end portion is H, and the conductor length from the power supply portion or the third end portion to the fourth end portion until the width gradually increases and becomes constant is H P , H / 3 ≦ H P ≦ 2×H / 3 Meet the antenna device.

3. A first conductor plate having a first end and a second end opposite the first end, with a power supply section provided near the second end; a second conductor plate having a third end connected to the power supply portion, a fourth end located at a position distant from the first conductor plate, and a plate surface whose width in a direction parallel to the first conductor plate increases from the third end toward the fourth end; a third conductor plate connected to the fourth end portion and facing the first conductor plate, the third conductor plate has a fifth end that is an open end opposite to the fourth end, An antenna device, wherein the width of the third conductor plate in the short side direction is 60% or more of the width of the first conductor plate in the short side direction.

4. When the conductor length from the power supply part or the third end to the fourth end is H, and the conductor length from the power supply part or the third end to the point where the width gradually increases toward the fourth end and becomes constant is H P , H / 3 ≦ H P ≦ 2×H / 3 The antenna device according to claim 3 , wherein

5. The antenna device according to claim 2 , wherein the first conductive plate is provided with a feed line connected to the feed portion.

6. the first conductive plate includes a dielectric layer; Let L1 be the length of the feed line, k1 be the wavelength shortening rate of the dielectric layer, L2 be the conductor length from the feed section or the third end to the fifth end, k2 be the wavelength shortening rate of the second conductor plate and the third conductor plate's surrounding medium, and λ be the wavelength in the air of the radio wave to be transmitted and received. λ / 4 ≦ (L1 / k1) + (L2 / k2) ≦ λ / 2 The antenna device according to claim 5 , wherein

7. 7. The antenna device according to claim 1, wherein a matching circuit is connected to the feed line.

8. The antenna device according to claim 7 , wherein the matching circuit has a capacitive impedance.

9. 9. The antenna device according to claim 1, wherein the feed line is a coplanar waveguide.

10. The antenna device according to claim 1 , wherein the feed line faces the third conductor plate.

11. When the conductor length from the power supply section or the third end to the fifth end is L2, the wavelength shortening rate of the second conductor plate and the surrounding medium of the third conductor plate is k2, and the wavelength in the air of the radio wave to be transmitted and received is λ, L2 / k2<λ / 4 The antenna device according to claim 1 , wherein the following is satisfied:

12. When the wavelength shortening rate of the medium between the first conductor plate and the third conductor plate is k and the wavelength of the radio wave in the air to be transmitted and received is λ, The antenna device according to claim 1 , wherein a distance between the first conductive plate and the third conductive plate is equal to or greater than 0.038×λ×k.

13. The antenna device according to claim 1 , wherein the third conductive plate is parallel to the first conductive plate.

14. The antenna device according to claim 13 , wherein the second conductive plate is perpendicular to the first conductive plate and the third conductive plate.

15. The antenna device according to claim 1 , wherein, in a plan view of the third conductor plate, the fifth end overlaps the first end or is located closer to the second end than the first end.

16. The antenna device according to claim 1 , wherein the first conductor plate is provided with a connector for connecting the power feed portion or a power feed line connected to the power feed portion to a cable external to the antenna device.

17. The antenna device according to claim 1 , which transmits and receives radio waves including 760 MHz.

18. Vehicle window glass; 18. A vehicle antenna system comprising: at least one antenna device according to claim 1 attached to the window glass or in the vicinity thereof.

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