JP2007325118A - Antenna apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To transmit/receive a plurality of electromagnetic waves of which frequencies are different from each other, in simple configuration. <P>SOLUTION: An antenna apparatus includes antenna patterns 16 which are formed on a metal sheet 12 so as to face each other with a dielectric substrate 14 inbetween, and leaks and radiates electromagnetic waves from the surface of the dielectric substrate 14 by feeding power to a transmission line using the antenna patterns 16. In such an antenna apparatus, the antenna patterns 16 are formed so as to alternately connect a capacitance component 22 in series and an inductance component 24 in parallel one by one, respectively from an input terminal 18 to a termination 20. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an antenna device, and more particularly to an antenna device that is mounted on a vehicle or the like and can transmit and receive electromagnetic waves corresponding to a plurality of media.

Conventionally, an antenna device capable of transmitting and receiving electromagnetic waves corresponding to a plurality of media is known (see, for example, Patent Document 1). This antenna device has antenna elements having different frequency characteristics corresponding to each medium. The plurality of antenna elements are arranged in a positional relationship such that one antenna device acts as a director of another antenna device in one antenna unit.
JP 2004-328330 A

  However, in the conventional antenna device, the plurality of antenna elements provided in one antenna unit constitute independent antennas. Therefore, in order to transmit and receive electromagnetic waves corresponding to a plurality of media, it is necessary to provide antenna elements suitable for transmitting and receiving those electromagnetic waves, and it is necessary to connect connection cables as feed lines. For this reason, the device itself becomes large.

  The present invention has been made in view of the above points, and an object thereof is to provide an antenna device capable of transmitting and receiving a plurality of electromagnetic waves having different frequencies with a simple configuration.

  The object is to have an antenna pattern formed on a metal plate so as to face each other with a dielectric interposed therebetween, and to feed electromagnetic waves from the surface of the dielectric by supplying power to the transmission line by the antenna pattern. An antenna device that radiates and leaks, wherein the antenna pattern has a structure in which a capacitance component is connected in series and an inductance component is alternately connected in parallel from an input end to a termination. Achieved.

  In the invention of this aspect, when power is fed from the input end to the end of the transmission line by the antenna pattern, the electromagnetic wave radiated from the surface of the dielectric has directivity in the direction corresponding to the frequency of the electromagnetic wave. That is, electromagnetic waves are radiated in different directions depending on the frequency of the electromagnetic waves. In such a configuration, a single transmission line may be provided to emit a plurality of electromagnetic waves. Therefore, according to the present invention, a plurality of electromagnetic waves having different frequencies can be transmitted and received with a simple configuration.

  In the antenna device described above, the radiation direction of the electromagnetic wave may be adjusted according to the size of the capacitance component and / or the inductance component.

  In this case, directivity control means for dynamically controlling the magnitude of the capacitance component and / or the inductance component may be provided.

  Further, in the antenna device described above, if the antenna pattern has a pair of strip lines which are branched in directions orthogonal to each other and fed with a phase shifted by 90 °, the circularly polarized wave and the elliptically polarized wave are provided. Wave electromagnetic waves can be transmitted and received.

  Furthermore, in the antenna device described above, if the axial ratio is adjusted according to the length and / or width of the pair of strip lines, the polarization of electromagnetic waves that can be transmitted and received can be adjusted.

  According to the present invention, a plurality of electromagnetic waves having different frequencies can be transmitted and received with a simple configuration.

  Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows a configuration diagram of an antenna device 10 according to a first embodiment of the present invention. 1A shows a side view, and FIG. 1B shows a plan view. FIG. 2 shows an equivalent circuit of the antenna device 10 of this embodiment. FIG. 3 is a diagram showing the relationship between the feeding direction and the maximum radiation direction of the radio wave in the antenna device 10 of the present embodiment.

  The antenna device 10 of the present embodiment is mounted on a vehicle, and a plurality of electromagnetic waves having different frequencies used in the vehicle (for example, 1.5 GHz band radio waves used in a GPS system and 2 used in a VICS system). This is a device that radiates three radio waves (5 GHz band radio wave and 5.8 GHz band radio wave used in the ETC system) as transmission / reception radio waves to the outside.

  As shown in FIG. 1, the antenna device 10 includes a metal plate 12 that is a ground conductor, a dielectric substrate 14 disposed so as to cover the metal plate 12, and an antenna formed on the dielectric substrate 14. And an antenna pattern 16 which is a conductor. That is, the antenna pattern 16 is formed on the grounded metal plate 12 so as to face each other with the dielectric substrate 14 interposed therebetween. The antenna pattern 16 is formed to extend linearly on the surface of the dielectric substrate 14.

  The antenna device 10 is made of a structure (left-handed medium; so-called metamaterial) in which both the dielectric constant and the magnetic permeability indicating the behavior when the electromagnetic wave propagates can be negative in appearance. The dielectric substrate 14 is made of a material such as a fluororesin such as tetrafluoroethylene or a glass epoxy resin, and the metal plate 12 and the antenna pattern 16 are both made of a metal material such as copper or titanium.

  The metal plate 12, the dielectric substrate 14, and the antenna pattern 16 constitute a transmission line through which electromagnetic waves propagate. The transmission line is fed via a coaxial cable. In this case, the fed electromagnetic wave is transmitted from the input end 18 (left end in FIG. 1), which is one end of the transmission line, toward the termination 20 (right end in FIG. 1), which is the other end. The termination 20 is terminated by a resistor.

  The antenna pattern 16 has a capacitance component 22 (each component value is C2) connected in series from the input end 18 to the end 20 to realize a left-handed medium, and is parallel to the ground side. And an inductance component 24 (each component value is L2). The capacitance component 22 and the inductance component 24 are alternately connected one by one from the input end 18 to the termination 20. The capacitance component 22 and the inductance component 24 are both composed of metal particles that are sufficiently smaller than the wavelength used for radio waves.

  The antenna pattern 16 is also connected in series with a capacitance component 30 (each component value is C1) in parallel with the ground side from the input end 18 to the terminal end 20 in order to realize a right-handed medium. And an inductance component 32 (each component value is L1). The capacitance component 30 and the inductance component 32 are alternately connected one by one from the input terminal 18 to the terminal end 20. The capacitance component 30 and the inductance component 32 are both composed of metal particles that are sufficiently smaller than the wavelength used for radio waves.

  In the configuration of the antenna device 10, when power is supplied from the input end 18, the electromagnetic wave propagates in the transmission line from the input end 18 toward the termination 20 and is terminated by the termination resistor. In the process of propagation of the electromagnetic wave in the transmission line, a part of the electromagnetic wave leaks from the surface of the dielectric substrate 14 and is radiated to the outside as a radio wave.

  At this time, the maximum radiation direction θ of the radio wave leaking from the surface of the dielectric substrate 14 changes according to the frequency of the electromagnetic wave used, and can be expressed by the following formula (1). Note that the maximum radiation direction θ is 0 ° in the direction perpendicular to the surface of the dielectric substrate 14, the direction side in which the electromagnetic wave propagates in the transmission line by feeding is +, and the direction side opposite to the direction in which the electromagnetic wave propagates Is-. Further, k0 is a wave number in free space, β is a propagation constant of the dielectric line, and is expressed by the following equation (2). Ω is the frequency of the electromagnetic wave.

θ = arcsin (β / k0) (1)
β = ω · √ (L1 · C1) −1 / (ω · √ (L2 · C2)) (2)
Regarding the equation (2), when the frequency ω of the electromagnetic wave is relatively large, the first term becomes dominant as compared with the second term. On the other hand, when the frequency ω of the electromagnetic wave is relatively small, the second term is It becomes superior to the first term. For this reason, when the frequency ω of the electromagnetic wave is relatively large, β indicates a value on the + side compared to when the frequency is relatively small, and the maximum radiation direction θ is on the direction side in which the electromagnetic wave propagates. In this case, the antenna device 10 is substantially equivalent to the state in which the capacitance component 22 and the inductance component 24 do not exist, and the capacitance component 30 and the inductance component 32 are alternately connected one by one from the input end 18 to the terminal end 20. It becomes a state almost equivalent to the thing. In addition, when the frequency ω of the electromagnetic wave is relatively small, β indicates a value on the − side, and the maximum radiation direction θ is on the opposite side to the direction in which the electromagnetic wave propagates, compared to when the frequency is relatively large. In this case, the antenna device 10 is substantially equivalent to a state in which the capacitance component 30 and the inductance component 32 do not exist, and the capacitance component 22 and the inductance component 24 are alternately connected one by one from the input end 18 to the terminal end 20. It becomes almost equivalent to the thing.

  That is, the capacitance component 30 and the inductance component 32 are more likely to function when the electromagnetic wave is at a high frequency and are less likely to function when the electromagnetic wave is at a lower frequency, while the capacitance component 22 and the inductance component 24 are lower in electromagnetic wave. It is easier to function when it is at high frequencies, and it is harder to function at high frequencies.

  In this regard, in the antenna device 10 of this embodiment, the maximum radiation direction of the radio wave leaked from the surface of the dielectric substrate 14 is directed from the input end 18 to the termination 20 at least in the antenna pattern 16 according to the frequency of the electromagnetic wave used. It can be made different in a range (in the xz plane) from the feeding direction to the opposite direction including the direction opposite to the feeding direction. Specifically, as shown in FIG. 3, when the frequency of electromagnetic waves is relatively large, the maximum radiation direction of the radio waves is on the power feeding direction side from the input end 18 to the terminal end 20 as compared to when the frequency is relatively small. When the frequency is relatively small, it can be on the side opposite to the feeding direction from the terminal end 20 to the input end 18 as compared with a relatively large frequency.

  For example, in a situation where the capacitance component 30 and the inductance component 32 are difficult to function in the radio wave band (1.5 GHz band) used in the GPS system, and the capacitance component 22 and the inductance component 24 are easy to function, When the use frequency in the 5.8 GHz band corresponding to the ETC system is in the antenna pattern 16, the antenna pattern 16 is substantially equivalent to the state in which the capacitance component 22 and the inductance component 24 do not exist, and the input end 18 to the termination 20. As a result, the capacitance component 30 is connected in parallel with the ground side and the structure in which the inductance component 32 is connected in series is almost equivalent. In this case, the capacitance component 30 and the inductance component 32 are substantially equivalent to those alternately connected one by one from the input end 18 to the termination end 20, and a normal right-handed medium is realized as the antenna pattern 16. .

  That is, in the 5.8 GHz band, as a right-handed medium, the direction in which electromagnetic waves are radiated is the side from the input end 18 toward the end 20. For this reason, in the antenna device 10, when the operating frequency at the time of feeding is the 5.8 GHz band corresponding to the ETC system, the maximum radiation direction of the radio wave leaking from the surface of the dielectric substrate 14 is the same direction as the feeding direction. (Forward direction). At this time, the angle θ in the maximum radiation direction of the radio wave is more susceptible to the component values C1 and L1 of the capacitance component 30 and the inductance component 32 than the component values C2 and L2 of the capacitance component 22 and the inductance component 24. This is in accordance with the component values C1 and L1.

  In the same situation as described above, when the frequency used during power feeding is in the 1.5 GHz band corresponding to the GPS system, the antenna pattern 16 has a capacitance component 22 connected in series from the input end 18 to the end 20 and is connected to the ground side. Is substantially equivalent to the structure in which the inductance component 24 is connected in parallel. In this case, the capacitance component 22 and the inductance component 24 are substantially equivalent to those alternately connected one by one from the input end 18 to the termination end 20, and a left-handed medium is realized as the antenna pattern 16.

  That is, in the 1.5 GHz band, as the left-handed medium, the direction in which electromagnetic waves are emitted is on the side opposite to the direction from the input end 18 toward the terminal end 20. For this reason, in the antenna device 10, when the operating frequency at the time of power supply is a 1.5 GHz band corresponding to the GPS system, the maximum radiation direction of radio waves leaking from the surface of the dielectric substrate 14 is opposite to the power supply direction. It will go in the direction (backward). At this time, the angle of the maximum radiation direction of the radio wave is more easily affected by the component values C2 and L2 of the capacitance component 22 and the inductance component 24 than the component values C1 and L1 of the capacitance component 30 and the inductance component 32. This is in accordance with the component values C2 and L2.

  Further, in the same situation as described above, when the frequency used at the time of power supply is a 2.5 GHz band corresponding to the VICS system, the antenna pattern 16 has a capacitance component 22 and an inductance component 32 in series from the input end 18 to the termination 20. It is almost equivalent to a structure in which the inductance component 24 and the capacitance component 30 are connected in parallel with the ground side. In this case, the antenna pattern 16 is realized by combining the characteristics of the right-handed medium and the left-handed medium.

  That is, in the intermediate 2.5 GHz band between the 1.5 GHz band and the 5.8 GHz band, the direction in which the electromagnetic wave is emitted corresponds to a combination of both characteristics of the right-handed medium and the left-handed medium. Become. For this reason, in the antenna device 10, when the operating frequency at the time of feeding is in the 2.5 GHz band corresponding to the VICS system, the maximum radiation direction of the radio wave leaking from the surface of the dielectric substrate 14 is substantially perpendicular to the surface. (Β = 0, θ = 0).

  As described above, in the antenna device 10 of this embodiment, the maximum radiation direction of the radio wave leaked from the surface of the dielectric substrate 14 is opposite to the feeding direction from the feeding direction in the antenna pattern 16 according to the frequency of the electromagnetic wave. In the 5.8 GHz band corresponding to the ETC system, the same direction as the power feeding direction (forward direction) is used, and the 1.5 GHz band corresponding to the GPS system. In FIG. 5, the direction opposite to the feeding direction (rear direction) can be set, and further, in the 2.5 GHz band corresponding to the VICS system, the direction can be almost perpendicular to the surface of the dielectric substrate 14.

  Further, in the antenna device 10 of the present embodiment, the maximum radiation direction of the radio wave leaking from the surface of the dielectric substrate 14 varies depending on the frequency of the electromagnetic wave as described above, but a plurality of radio waves having different frequencies are radiated. In addition, a single transmission line may be provided by the metal plate 12, the dielectric substrate 14, and the antenna pattern 16, and it is not necessary to provide a transmission line for each corresponding frequency. Therefore, according to the antenna device 10 of the present embodiment, it is possible to transmit and receive a plurality of radio waves having different frequencies with a simple configuration, and it is possible to realize transmission and reception corresponding to a plurality of media. ing. For this reason, it is not necessary to provide a plurality of connection cables as antenna elements or feed lines corresponding to the frequencies of the respective media, and the antenna device itself can be reduced in size.

  Further, in this embodiment, with respect to the equation (2), β varies according to the component values C1 and L1 of the capacitance component 30 and the inductance component 32 or the component values C2 and L2 of the capacitance component 22 and the inductance component 24. Therefore, the maximum radiation direction θ of the radio wave can also be adjusted according to the sizes C1 and L1 of the capacitance component 30 and the inductance component 32 or the sizes C2 and L2 of the capacitance component 22 and the inductance component 24. Therefore, according to the configuration of the present embodiment, the maximum radiation direction of the radio wave related to the antenna directivity of each medium from the surface of the dielectric substrate 14 is determined based on the sizes C1 and L1 of the capacitance component 30 and the inductance component 32 and the capacitance component 22. In addition, the inductance component 24 can be controlled in an arbitrary direction by changing the sizes C2 and L2.

  In this regard, by appropriately setting the component values C1, L1, C2, and L2, the plurality of media (for example, the above-described 1.5 GHz band GPS system, 2.5 GHz band VICS system, and 5. As shown in FIG. 3, the maximum radiation direction of radio waves in the frequency band corresponding to the 8 GHz band ETC system) is shown in FIG. 3 in the power feeding direction side from the input end 18 to the terminal end 20 in the high frequency band and in the low frequency band. It is possible to adjust in the direction opposite to the feeding direction from the terminal 20 to the input end 18 and in the direction substantially perpendicular to the surface of the dielectric substrate 14 in the intermediate frequency band. Further, in all frequency bands of each medium, the maximum radiation direction of radio waves is not inclined from the direction substantially perpendicular to the surface of the dielectric substrate 14 toward the end 20 side, and as shown in FIG. Adjustments can be made in the direction substantially perpendicular to the surface of the dielectric substrate 14 and in the direction opposite to the feeding direction from the terminal 20 to the input end 18 in the lower frequency band (θ ≦ 0). As shown in FIG. 4 (B), it is also possible to adjust only in the counter feed direction from the terminal 20 to the input terminal 18 in the frequency band of each medium (θ <0).

  Therefore, for example, as shown in FIG. 5, the antenna device 10 of the present embodiment is adapted to the ETC system in order from the side closer to the horizontal direction of the vehicle traveling direction through the windshield surface of the vehicle. When mounting on a vehicle so that radio waves in the 2.5 GHz band corresponding to the band, the VICS system, and the 1.5 GHz band corresponding to the GPS system are radiated, the mounting is performed on the metal plate 12 and the dielectric substrate 14. Even if the transmission line composed of the antenna pattern 16 is arranged so as to extend parallel to the windshield surface, the above-described mounting is arranged so that the transmission line extends parallel to the vehicle body, that is, horizontally. Even if it is a thing, it is possible to radiate | emulate each electromagnetic wave to the desired direction diagonally above the vehicle body through the windshield surface.

  In the first embodiment described above, the antenna device 10 has the antenna pattern 16 formed to extend linearly on the surface of the dielectric substrate 14, thereby realizing a linearly polarized antenna. In contrast, in the second embodiment of the present invention, a circularly polarized antenna or an elliptically polarized antenna is realized.

  FIG. 6 is a plan view of an antenna device 100 according to the second embodiment of the present invention. In the present embodiment, the same components as those shown in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted or simplified.

  The antenna device 100 according to the present embodiment is mounted on a vehicle, like the antenna device 10 according to the first embodiment, and radiates a plurality of electromagnetic waves having different frequencies used in the vehicle as transmission / reception radio waves to the outside. The apparatus includes a metal plate 12 and a dielectric substrate 14. The antenna device 100 includes an antenna pattern 102 that is an antenna conductor formed on the dielectric substrate 14.

  The antenna pattern 102 extends linearly from the input end 18 to the surface of the dielectric substrate 14 and branches to two lines from a branch point 104 on the opposite side of the line from the input end 18. Is formed. The two branch lines 102a and 102b from the branch point 104 in the antenna pattern 102 are arranged so as to be orthogonal to each other (at an angle of 90 °). The antenna pattern 102 is made of a metal material such as copper or titanium.

  The metal plate 12, the dielectric substrate 14, and the antenna pattern 102 constitute a transmission line through which electromagnetic waves propagate. The transmission line is fed via a coaxial cable. In this case, the fed electromagnetic waves are transmitted from the input end 18 via the branch point 104 toward the respective terminations 106a and 106b of the branch lines 102a and 102b. Both terminations 106a and 106b are terminated by resistors.

  The branch lines 102a and 102b of the antenna pattern 102 are connected to the capacitance component 22 in series from the branch point 104 to the terminal ends 106a and 106b to realize a left-handed medium, and in parallel with the ground side. 24 has a connected structure. The branch line 102 a has a straight line distance L 1 from the branch point 104 to the nearest capacitance component 22 as viewed from the branch point 104, and the branch line 102 a is the capacitance closest to the branch point 104 from the branch point 104. It has a linear distance L2 to component 22. One of the linear distances L1 and L2 (the direct communication distance L1 in FIG. 6) is set longer than the other (the linear distance L2 in FIG. 6) by a quarter wavelength of the transmitted / received radio wave. That is, one of the branch lines 102a and 102b has a length of ¼ wavelength of the transmitted / received radio wave from the branch point 104 to the nearest capacitance component 24 so that the phase of the transmitted / received signal is shifted by 90 ° from each other. It is formed so long.

  In order to realize a right-handed medium, the branch lines 102a and 102b have a capacitance component 30 connected in parallel with the ground side from the branch point 104 to the terminations 106a and 106b, and an inductance component 32 connected in series. Have a structure.

  In the configuration of the antenna device 100 described above, when power is supplied from the input end 18, the electromagnetic wave passes through the branch point 104 from the input end 18 toward the terminal ends 106a and 106b of the branch lines 102a and 102b. Is terminated by a terminating resistor. In the process of propagation of the electromagnetic wave in the transmission line, a part of the electromagnetic wave leaks from the surface of the dielectric substrate 14 and is radiated to the outside as a radio wave.

  At this time, the maximum radiation direction of the radio wave leaked from the surface of the dielectric substrate 14 is obtained by synthesizing the directivity of the radio wave leaked by using each of the two branch lines 102a and 102b. Accordingly, the antenna pattern 102 differs in the range from the propagation direction of the electromagnetic wave due to the feeding at the branch lines 102a and 102b to the direction opposite to the propagation direction.

  Specifically, the maximum radiation direction of the radio waves on the branch lines 102a and 102 is on the power feeding direction side from the branch point 104 to the terminal points 106a and 106b when the frequency of the electromagnetic wave is relatively large compared to when the frequency is relatively small. On the contrary, when the frequency of the electromagnetic wave is relatively small, it is on the side opposite to the feeding direction from the terminal ends 106a and 106b to the input end 104 as compared with when the frequency is relatively large. The maximum radiation direction of the combined wave is on the feeding direction side from the input end 18 when the frequency of the electromagnetic wave is relatively large, and is relatively large when the frequency of the electromagnetic wave is relatively small. Compared to the case, it is on the side opposite to the feeding direction toward the input end 18.

  For example, in the 5.8 GHz band corresponding to the ETC system, the maximum radiation direction of the synthesized wave is the same direction (forward direction) as the power feeding direction from the input end 18 to the branch point 104 and corresponds to the GPS system. In the 1.5 GHz band, the direction is the direction opposite to the feeding direction (rear direction), and in the 2.5 GHz band corresponding to the VICS system, the direction is substantially perpendicular to the surface of the dielectric substrate 14.

  Further, in such a configuration, a synthesized wave obtained by synthesizing the transmission / reception signal on the branch line 102a and the transmission / reception signal on the branch path 102b with a 90 ° phase shift is obtained. Therefore, in the antenna device 100, a circularly polarized wave or an elliptically polarized wave is generated by a pair of branch lines 102a and 102b which the antenna pattern 102 has orthogonal to each other and a configuration for shifting the phase by 90 degrees as a phase shifter. It is possible to send and receive.

  Further, in the antenna device 100 of the present embodiment, the maximum radiation direction of the radio wave leaked from the surface of the dielectric substrate 14 differs depending on the frequency of the electromagnetic wave, but when radiating a plurality of radio waves having different frequencies, A single transmission line may be provided by the metal plate 12, the dielectric substrate 14, and the antenna pattern 102, and it is not necessary to provide a transmission line for each corresponding frequency. Therefore, also in the antenna device 100 of the present embodiment, similarly to the antenna device 10 of the first embodiment described above, it is possible to transmit and receive a plurality of radio waves having different frequencies with a simple configuration. There is no need to provide a plurality of connection cables as elements and feed lines corresponding to the frequency of each medium, and the antenna device itself can be miniaturized.

  In the antenna device 100 according to the present embodiment, by changing at least one of the width and the length of each metal strip line composed of the pair of branch lines 102a and 102b of the antenna pattern 102, the distance between the branch lines 102a and 102b is changed. It is possible to adjust the axial ratio of elliptically polarized waves by changing the amount of power distribution. In this regard, it is possible to adjust the polarization of electromagnetic waves that can be transmitted and received by the antenna device 100.

  In the antenna device 100 of the present embodiment, the branch lines 102a and 102b of the antenna pattern 102 are at angles of 0 ° and 90 ° with respect to the straight line passing from the input end 18 to the branch point 104 as shown in FIG. Further, as shown in FIG. 8, it may be arranged so as to form an angle of 45 ° with respect to a straight line passing through the branch point 104 from the input end 18 as shown in FIG. However, in both configurations, it is necessary to provide a phase shifter 110 that shifts the phase by 90 ° at the branch point 104.

  In the first and second embodiments described above, the antennas are selected according to the sizes of the capacitance component 22 and the inductance component 24 (C2, L2) and the sizes of the capacitance component 30 and the inductance component 32 (C1, L1). Although the maximum radiation direction of each radio wave related to directivity can be controlled in an arbitrary direction, these component values C2, L2, C1, and L1 are dynamically changed to appropriately control the maximum radiation direction of radio waves. It is good to do. At this time, as a method of dynamically changing the component values C2, L2, C1, and L1, a technique such as varicap (varactor) or RF-MEMS may be used. According to such a configuration, It becomes possible to change the maximum radiation direction of the radio wave from moment to moment according to the case.

  In the first and second embodiments described above, the present invention is applied to a system equipped with three media: a 1.5 GHz band GPS system, a 2.5 GHz band VICS system, and a 5.8 GHz band ETC system. However, the present invention is not limited to this, and may be applied to a system equipped with at least two of these three media.

It is a block diagram of the antenna apparatus which is 1st Example of this invention. It is the equivalent circuit of the antenna apparatus of a present Example. It is the figure showing the relationship between the direction of electric power feeding in the antenna apparatus of a present Example, and the maximum radiation | emission direction of an electromagnetic wave. It is a figure showing an example of the maximum radiation direction of the electromagnetic wave in the antenna apparatus of a present Example. It is the figure showing an example which mounted the antenna apparatus of a present Example in the vehicle. It is a top view of the antenna apparatus which is 2nd Example of this invention. It is a block diagram of an example of the antenna apparatus of a present Example. It is a block diagram of an example of the antenna apparatus of a present Example.

Explanation of symbols

10,100 Antenna device 12 Metal plate 14 Dielectric substrate 16, 102 Antenna pattern 18 Input end 20, 106a, 106b Termination 104 Branch point

Claims (5)

An antenna pattern is formed on a metal plate so as to face each other with a dielectric interposed therebetween, and electromagnetic waves are leaked and radiated from the surface of the dielectric by supplying power to the transmission line by the antenna pattern. An antenna device,
The antenna device has a structure in which a capacitance component is connected in series and an inductance component is alternately connected in parallel from the input end to the end.   The antenna device according to claim 1, wherein the radiation direction of the electromagnetic wave is adjusted according to a size of the capacitance component and / or the inductance component.   3. The antenna device according to claim 2, further comprising directivity control means for dynamically controlling the magnitude of the capacitance component and / or the inductance component.   4. The antenna device according to claim 1, wherein the antenna pattern includes a pair of strip lines that are branched in directions orthogonal to each other and fed with a phase shifted by 90 °. .   The antenna apparatus according to claim 4, wherein the axial ratio is adjusted according to a length and / or a width of the pair of strip lines.