JP7038634B2 - Antenna device and railroad vehicle - Google Patents

Description

The techniques disclosed herein relate to antenna devices and railroad vehicles.

The shared antenna for overhead line voltage detection and wireless communication is mounted on the roof of the train. The shared antenna has a use for an overhead line voltage detection system and a use for a wireless communication system.

The overhead wire voltage detection system is a system for confirming that the voltage of the overhead wire wired above the train is in a pressurized state. The overhead line voltage detection system is used when an AC power supply is used.

On the other hand, the wireless communication system is used for communication between a base station on the ground side and a mobile station on the vehicle side, or for receiving a protective radio in the event of an emergency with an antenna mounted on the vehicle. To. The frequency band used for the communication is, for example, a VHF band or a UHF band.

The shared antenna for overhead line voltage detection and wireless communication includes a planar conductor and a columnar conductor (see, for example, Non-Patent Document 1).

AC voltage is induced in the columnar conductor and the planar conductor at the overhead wire power supply frequency due to the capacitance generated between the columnar conductor and the planar conductor. The planar conductor then operates as a monopole antenna at radio frequencies.

Tadamitsu Kuroda, Hajime Kubota, Sakae Nagaoka, Takashi Kirenkawa, Yoshihiro Takeichi, "Tokaido Shinkansen Overhead Line Voltage Detection / Private Wireless Shared Antenna", Mitsubishi Electric Technical Report, Vol. 38 No. 4, 1964

However, in the configuration as shown in Non-Patent Document 1, the length L of the columnar conductor corresponds to 0.25 wavelength, which is relatively long. Therefore, there is a problem that the wind noise when the train is running is loud.

Further, since the length L of the columnar conductor is relatively long as described above, the columnar conductor is electromagnetically coupled to the planar conductor at a radio frequency. Then, a high frequency current flows through the columnar conductor.

Therefore, there is a problem that the radiation from the high frequency current flowing through the columnar conductor in the zenith direction becomes large and the gain in the horizontal direction decreases.

The technique disclosed in the present specification has been made to solve the above-mentioned problems, and an object thereof is to provide a technique for suppressing wind noise and increasing horizontal gain. It is a thing.

The first aspect of the technique disclosed in the present specification is a ground conductor plate, a substrate connected to the ground conductor plate, and the ground conductor formed on the first surface of the substrate and the ground conductor of the substrate. A first flat conductor located on the side opposite to the end connected to the plate, and the ground conductor plate formed on the first surface of the substrate and separated from the first flat conductor. A second planar conductor in contact with, a columnar conductor arranged on the side of the substrate opposite to the end connected to the ground conductor plate, and a surface of the substrate opposite to the first surface. The second end is formed on the second surface, the first end is connected to the ground conductor plate via a radio terminal, and the end is opposite to the first end. The first open end line, which is an open end whose portion is arranged at a position overlapping the first plane conductor in a plan view, and the second surface of the substrate, the third end is an overhead wire. The fourth end, which is connected to the ground conductor plate via the voltage detection terminal and is the end opposite to the third end, is a short-circuit end short-circuited with the first flat conductor. , The first short-circuit line at the tip and the second surface of the substrate, the fifth end is connected to the columnar conductor via a connecting conductor, and is opposite to the fifth end. A sixth end, which is a side end, is a short-circuit end that short-circuits with the first flat conductor, a second tip short-circuit line, and a seventh end formed on the second surface of the substrate. The portion is connected to the second plane conductor, and the eighth end portion, which is the end portion opposite to the seventh end portion, is arranged at a position where it overlaps with the first plane conductor in a plan view. A region that is provided with a second open end line, which is an open end, and separates the first plane conductor from the second plane conductor is defined as a separation region, and the first plane conductor is separated from the first plane conductor. A slit extending from the region toward the columnar conductor is formed, and the slit is formed at a position sandwiched between the first open-ended line and the second open-ended line in a plan view.

In addition, a second aspect of the technique disclosed in the present specification comprises an antenna device according to the above aspect.

The first aspect of the technique disclosed in the present specification is a ground conductor plate, a substrate connected to the ground conductor plate, and the ground conductor formed on the first surface of the substrate and the ground conductor of the substrate. A first flat conductor located on the side opposite to the end connected to the plate, and the ground conductor plate formed on the first surface of the substrate and separated from the first flat conductor. A second planar conductor in contact with, a columnar conductor arranged on the side of the substrate opposite to the end connected to the ground conductor plate, and a surface of the substrate opposite to the first surface. The second end is formed on the second surface, the first end is connected to the ground conductor plate via a radio terminal, and the end is opposite to the first end. The first open end line, which is an open end whose portion is arranged at a position overlapping the first plane conductor in a plan view, and the second surface of the substrate, the third end is an overhead wire. The fourth end, which is connected to the ground conductor plate via the voltage detection terminal and is the end opposite to the third end, is a short-circuit end short-circuited with the first flat conductor. , The first short-circuit line at the tip and the second surface of the substrate, the fifth end is connected to the columnar conductor via a connecting conductor, and is opposite to the fifth end. A sixth end, which is a side end, is a short-circuit end that short-circuits with the first flat conductor, a second tip short-circuit line, and a seventh end formed on the second surface of the substrate. The portion is connected to the second plane conductor, and the eighth end portion, which is the end portion opposite to the seventh end portion, is arranged at a position where it overlaps with the first plane conductor in a plan view. A region that is provided with a second open end line, which is an open end, and separates the first plane conductor from the second plane conductor is defined as a separation region, and the first plane conductor is separated from the first plane conductor. A slit extending from the region toward the columnar conductor is formed, and the slit is formed at a position sandwiched between the first open-ended line and the second open-ended line in a plan view. According to such a configuration, the slit is formed at a position sandwiched between the first open-ended line and the second open-ended line in a plan view, thereby suppressing wind noise and gaining in the horizontal direction. Even when the length of the columnar conductor is shortened in order to increase the impedance, the impedance can be properly matched.

In addition, a second aspect of the technique disclosed in the present specification comprises an antenna device according to the above aspect. According to such a configuration, even when the length of the columnar conductor is shortened in order to suppress the wind noise and increase the horizontal gain, the impedance can be appropriately matched.

Also, the objectives, features, aspects and advantages of the technology disclosed herein will be further clarified by the detailed description and accompanying drawings set forth below.

It is a figure which shows the example of the configuration of the shared antenna of overhead line voltage detection and wireless communication schematically. It is a figure which shows typically the example of the structure of the antenna device which concerns on embodiment. It is a figure which shows the example of the equivalent circuit in the radio frequency of the antenna device which concerns on embodiment. It is a figure which shows the example of the operation of the antenna device which concerns on embodiment at a radio frequency. It is a figure which shows the example of the ordinary monopole structure which does not have a slit and a tip open line. It is a figure which shows the calculation result of the input impedance seen from the radio terminal of the antenna device which concerns on embodiment. It is a figure which shows the calculation result of the radiation pattern in the horizontal plane of the vertical polarization in _fl of the antenna device which concerns on embodiment. It is a figure which shows the calculation result of the radiation pattern in the horizontal plane of the vertical polarization in _ph of the antenna device which concerns on embodiment. It is a figure which shows typically the example of the structure of the antenna device which concerns on embodiment. It is a figure which shows the example of the equivalent circuit in the radio frequency of the antenna device which concerns on embodiment. It is a figure which shows the calculation result of the input impedance seen from the radio terminal of the antenna device which concerns on embodiment. It is a figure which shows typically the example of the structure of the antenna device which concerns on embodiment.

Hereinafter, embodiments will be described with reference to the attached drawings.

It should be noted that the drawings are shown schematically, and for convenience of explanation, the configuration is omitted or the configuration is simplified as appropriate. Further, the interrelationship between the sizes and positions of the configurations and the like shown in different drawings is not always accurately described and can be changed as appropriate. Further, even in a drawing such as a plan view which is not a cross-sectional view, hatching may be added to facilitate understanding of the contents of the embodiment.

Further, in the description shown below, similar components are illustrated with the same reference numerals, and their names and functions are the same. Therefore, detailed description of them may be omitted to avoid duplication.

Also, in the description described below, a specific position and direction such as "top", "bottom", "left", "right", "side", "bottom", "front" or "back". Even if terms that mean are used, these terms are used for convenience to facilitate understanding of the content of the embodiments and have nothing to do with the direction in which they are actually implemented. It doesn't.

Also, even if ordinal numbers such as "first" or "second" may be used in the description described below, these terms should be used to understand the content of the embodiment. It is used for convenience for the sake of facilitation, and is not limited to the order that can occur due to these ordinal numbers.

<First Embodiment>
Hereinafter, the antenna device and the railroad vehicle according to the present embodiment will be described. For convenience of explanation, first, the configuration of an antenna device having a relatively long columnar conductor will be described.

<About the configuration of the antenna device>
FIG. 1 is a diagram schematically showing an example of a configuration of a shared antenna for overhead line voltage detection and wireless communication. As an example is shown in FIG. 1, the shared antenna includes a planar conductor 12a and a columnar conductor 6.

More specifically, the shared antenna includes a wireless terminal 1, an overhead wire voltage detection terminal 2, a columnar conductor 6, a substrate 11, a flat conductor 12a, a tip open line 21, a tip short circuit line 31a, and a tip short circuit line. 32, a short-circuit point 41, a short-circuit point 42, a ground conductor plate 51, and a connecting conductor 61 are provided.

The flat conductor 12a is formed on the back surface (that is, the surface on the back side of the paper surface) of the substrate 11 installed substantially perpendicular to the ground conductor plate 51. Further, the tip open line 21, the tip short-circuit line 31a, and the tip short-circuit line 32 are formed on the surface of the substrate 11 (the surface on the front side of the paper surface).

The columnar conductor 6 is installed in the vicinity of the upper side of the substrate 11 substantially parallel to the substrate 11. Normally, the overhead wire 101 is installed above the columnar conductor 6 at intervals.

One end of the open-ended line 21 is connected to the wireless terminal 1, and the end of the short-circuited line 31a on the opposite side of the short-circuit point 41 is connected to the overhead wire voltage detection terminal 2.

The overhead wire voltage detection terminal 2 is installed between one end of the tip short-circuit line 31a and the ground conductor plate 51. The overhead wire voltage detection terminal 2 detects the overhead wire detection voltage. One end of the tip short-circuit line 32 is connected to the columnar conductor 6 via the connecting conductor 61.

The other end of the tip short-circuit line 31a is short-circuited to the flat conductor 12a by the short-circuit point 41. Further, the other end of the tip short-circuit line 32 is short-circuited to the flat conductor 12a by the short-circuit point 42.

The open-ended line 21 has an electric length of about 1/4 wavelength at the radio frequency, and is installed to cut off the radio terminal 1 and the planar conductor 12a at the overhead wire power supply frequency and short-circuit at the radio frequency. ..

The tip short-circuit line 31a has an electric length of about 1/4 wavelength at the radio frequency, and is installed to conduct the overhead wire voltage detection terminal 2 and the flat conductor 12a at the overhead wire power supply frequency and to cut off at the radio frequency. ing.

The tip short-circuit line 32 has an electric length of about 1/4 wavelength at a radio frequency, and is installed to conduct the planar conductor 12a and the columnar conductor 6 at the overhead wire power supply frequency and to cut off at the radio frequency. ..

The columnar conductor 6 operates as a conductor for detecting the overhead wire voltage. On the other hand, the flat conductor 12a has a function as a radiation element for wireless communication and a function as a conductor for detecting overhead wire voltage.

An AC voltage is induced in the columnar conductor 6 and the planar conductor 12a at the overhead wire power supply frequency by the capacitance 71 generated between the columnar conductor 6 and the planar conductor 12a. Then, the planar conductor 12a operates as a monopole antenna at a radio frequency.

FIG. 2 is a diagram schematically showing an example of the configuration of the antenna device according to the present embodiment. Further, FIG. 3 is a diagram showing an example of an equivalent circuit at the radio frequency of the antenna device according to the present embodiment.

Further, FIG. 4 is a diagram showing an example of the operation of the antenna device according to the present embodiment at a radio frequency. Further, FIG. 5 is a diagram showing an example of a normal monopole structure having no slit and an open-ended line.

Further, FIG. 6 is a diagram showing a calculation result of the input impedance seen from the wireless terminal of the antenna device according to the present embodiment. Further, FIG. 7 is a diagram showing the calculation result of the radiation pattern of the antenna device according to the present embodiment in the horizontal plane of vertically polarized _waves in f. Further, FIG. 8 is a diagram showing the calculation result of the radiation pattern of the antenna device according to the present embodiment in the horizontal plane of vertical polarization at _fh .

As an example shown in FIG. 2, the antenna device according to the present embodiment includes a wireless terminal 1, an overhead wire voltage detection terminal 2, a columnar conductor 6, a substrate 11, a flat conductor 12, a flat conductor 13, and a slit. 16, tip open line 21, tip open line 22, tip short circuit line 31, tip short circuit line 32, short circuit point 41, short circuit point 42, connection point 46, ground conductor plate 51, and connection conductor. It is equipped with 61.

The antenna device according to this embodiment is a shared antenna for overhead line voltage detection and wireless communication. The frequency of the overhead wire power supply is 50 Hz, 60 Hz, or the like. As the frequency of the radio signal, a VHF band, a UHF band, or the like is used. Here, the center frequency of the frequency band of the radio signal used is f ₀ , the lower limit frequency is f _l , and the upper limit frequency is f _h .

The ground conductor plate 51 is a plate-shaped conductor, and for example, it is conceivable to use the roof of a train as the ground conductor plate 51. Here, it is assumed that the ground conductor plate 51 is substantially parallel to the horizontal plane (that is, the xy plane in FIG. 2).

The substrate 11 is connected substantially vertically to the ground conductor plate 51. The flat conductor 12 and the flat conductor 13 are each formed on the back surface of the substrate 11 (that is, the surface on the back side of the paper surface in FIG. 2).

The flat conductor 12 is located on the + z side of the back surface of the substrate 11, that is, on the side opposite to the end portion connected to the ground conductor plate 51.

The columnar conductor 6 is installed in the vicinity of the upper side of the substrate 11 substantially parallel to the substrate 11. That is, the columnar conductor 6 is arranged on the side of the substrate 11 opposite to the end portion connected to the ground conductor plate 51. The length L of the columnar conductor 6 is 0.2 wavelength or less at _f0 .

The plane conductor 13 is arranged at the lower part of the substrate 11, that is, a portion of the substrate 11 close to the ground conductor plate 51. The flat conductor 13 is in contact with the ground conductor plate 51.

The plane conductor 12 is installed in the vicinity of the plane conductor 12 on the upper part of the plane conductor 13, but is not connected to the plane conductor 13. That is, the plane conductor 12 and the plane conductor 13 are arranged so as to be separated from each other with the separation region 100.

Further, a slit 16 is formed upward from the lower side of the plane conductor 12. That is, the planar conductor 12 is formed with a slit 16 extending in the direction approaching the columnar conductor 6 from the separation region 100.

The length of the slit 16 is an electric length of about 1/4 wavelength at _f0 (that is, about 1/4 wavelength at an effective wavelength in consideration of wavelength shortening by the substrate 11).

The tip open line 21, the tip open line 22, the tip short-circuit line 31, and the tip short-circuit line 32 are formed on the surface of the substrate 11 (that is, the surface on the front side of the paper in FIG. 2).

The wireless terminal 1 is installed between one end of the open-ended line 21 and the ground conductor plate 51. Wireless signals are transmitted and received by the wireless terminal 1.

One end of the open-ended line 22 is connected to the planar conductor 13 at the connection point 46. The other end of the open-ended line 21 and the other end of the open-ended line 22 are open ends arranged at positions overlapping the flat conductor 12 in a plan view. The open-ended line 22 is installed on the plane conductor 12 on the side opposite to the side on which the open-ended line 21 is located when viewed from the slit 16.

The overhead wire voltage detection terminal 2 is installed between one end of the tip short-circuit line 31 and the ground conductor plate 51. Then, the overhead wire voltage is detected by the overhead wire voltage detection terminal 2. One end of the tip short-circuit line 32 is connected to the columnar conductor 6 via the connecting conductor 61.

The other end of the tip short-circuit line 31 is short-circuited to the flat conductor 12 by the short-circuit point 41. The other end of the tip short-circuit line 32 is short-circuited to the flat conductor 12 by the short-circuit point 42.

The open-ended line 21 and the short-circuited-tip line 31 are transmission lines having the flat conductor 13 as the ground at one end thereof and the flat conductor 12 as the ground at the other end.

On the other hand, the tip open line 22 and the tip short circuit line 32 are transmission lines with the flat conductor 12 as the ground.

The open-ended line 21 is installed to cut off the wireless terminal 1 and the flat conductor 12 at the overhead wire power supply frequency.

The open-ended line 22 has an electric length of about 1/4 wavelength at _f0 (that is, about 1/4 wavelength in consideration of wavelength shortening due to the substrate 11), and the flat conductor 12 and the flat conductor 13 are combined with each other. It is installed to cut off at the overhead line power supply frequency and short-circuit at the radio frequency.

The tip short-circuit line 31 has an electric length of about 1/4 wavelength at _f0 , and is installed to conduct the overhead wire voltage detection terminal 2 and the flat conductor 12 at the overhead wire power supply frequency and to cut off at the radio frequency. ing.

The tip short-circuit line 32 has an electric length of about 1/4 wavelength at _f0 , and is installed to conduct the planar conductor 12 and the columnar conductor 6 at the overhead wire power supply frequency and to cut off at the radio frequency. ..

<About the operation of the antenna device>
Next, the operation of the antenna device according to the present embodiment will be described with reference to FIGS. 2 to 8.

First, the overhead wire voltage detection function will be described. Normally, the overhead wire 101 is installed above the columnar conductor 6 at intervals. Then, a capacitance is generated between the overhead wire 101 and the columnar conductor 6 and between the overhead wire 101 and the planar conductor 12.

Here, the columnar conductor 6 and the flat conductor 12 are conducted by the tip short-circuit line 32 at the overhead wire power supply frequency. Further, the flat conductor 12 is cut off from the wireless terminal 1, the ground conductor plate 51, and the flat conductor 13 at the overhead wire power supply frequency, and is electrically connected to the overhead wire voltage detection terminal 2 by the tip short-circuit line 31. There is.

On the other hand, the radio terminal 1 and the flat conductor 12 are blocked by the open-ended line 21 at the overhead wire power supply frequency. Further, the flat conductor 12 and the flat conductor 13 are also cut off by the open-ended line 22 at the overhead wire power supply frequency.

Therefore, an AC voltage is induced in the columnar conductor 6 and the planar conductor 12 at the overhead wire power supply frequency due to the capacitance generated between the columnar conductor 6 and the planar conductor 12. Then, this AC voltage can be detected by the overhead wire voltage detection terminal 2.

In order to increase the overhead wire detection voltage, it is necessary to increase the capacitance generated between the overhead wire 101 and the columnar conductor 6 and between the overhead wire 101 and the planar conductor 12.

The capacitance can be increased by increasing the length of the columnar conductor 6 or by increasing the size of the planar conductor 12.

Next, the wireless communication function will be described. When an electric signal is input at a radio frequency by the radio terminal 1, a high frequency current flows through the open-ended line 21.

The open-ended line 21 can be regarded as a reactance connected in series between the radio terminal 1 and the planar conductor 12. Therefore, a high-frequency current mainly flows in the plane conductor 12 in the z-axis direction of FIG. 2 via the open-ended line 21, and the plane conductor 12 resonates as a monopole, so that electromagnetic waves are radiated from the plane conductor 12.

Here, the flat conductor 12 and the overhead wire voltage detection terminal 2 are cut off by the tip short-circuit line 31 at the radio frequency. Further, the flat conductor 12 and the columnar conductor 6 are blocked by the tip short-circuit line 32 at the radio frequency.

FIG. 3 is a diagram showing an example of an equivalent circuit at a radio frequency of the antenna device according to the present embodiment. The resonance of the planar conductor 12 can be regarded as the series resonance circuit 201 including the capacitance 202, the inductance 203, and the resistance 204 in FIG.

If the electrical length of the open-ended line 21 is about 1/4 wavelength, it can be considered that the wireless terminal 1 and the flat conductor 12 are short-circuited.

Further, if the electric length of the open-ended line 21 is 1/4 wavelength or less, the open-ended line 21 can be regarded as a capacitance connected in series between the radio terminal 1 and the planar conductor 12.

Further, if the electric length of the open-ended line 21 is 1/4 wavelength or more, the open-ended line 21 can be regarded as an inductance connected in series between the radio terminal 1 and the planar conductor 12.

Therefore, by changing the length of the open-ended line 21, the imaginary portion of the input impedance of the antenna can be adjusted to be approximately 0 at f ₀ .

Further, in the antenna device according to the present embodiment, the length L of the columnar conductor 6 is shortened to 0.2 wavelength or less at f ₀ to suppress the amount of electromagnetic field coupling between the planar conductor 12 and the columnar conductor 6. By doing so, the high frequency current flowing through the columnar conductor 6 can be reduced.

Therefore, the radiation from the high frequency current flowing through the columnar conductor 6 in the zenith direction (that is, the + z direction in FIG. 2) can be suppressed, and as a result, the radiation from the high frequency current flowing through the plane conductor 12 becomes large. The gain in the horizontal direction (that is, the xy plane in FIG. 2) can be improved.

On the other hand, when the length L of the columnar conductor 6 is f ₀ and is shorter than the 0.25 wavelength, the actual portion of the input impedance of the antenna device becomes low. Therefore, it becomes difficult to maintain impedance matching.

Here, when the length L of the columnar conductor 6 is f ₀ and the wavelength is about 0.25, in addition to the mode in which the planar conductor 12 resonates as a monopole, the planar conductor 12 and the columnar conductor 6 are electromagnetic. There is a mode in which the columnar conductor 6 and the upper part of the planar conductor 12 resonate as dipoles by field coupling.

Since these two resonance modes have two resonance characteristics, it was possible to increase the input impedance real part of the antenna device and realize impedance matching.

However, when the length L of the columnar conductor 6 is f ₀ and is 0.2 wavelength or less and short, the amount of electromagnetic field coupling between the planar conductor 12 and the columnar conductor 6 is small. Therefore, only the mode in which the plane conductor 12 resonates as a monopole is available. This lowers the real part of the input impedance of the antenna device, making it difficult to maintain impedance matching.

On the other hand, when the length L of the columnar conductor 6 is shortened to reduce the size of the antenna device, it is desirable to increase the size of the flat conductor 12 in order to secure the overhead wire voltage detection performance.

Therefore, a slit 16 is formed in the flat conductor 12, and the open tip line 22 is arranged on the side of the flat conductor 12 opposite to the side where the open tip line 21 is located when viewed from the slit 16.

FIG. 4 is a diagram showing an example of operation of the antenna device according to the present embodiment at a radio frequency. In this case, it can be considered that the open-ended line 22 in FIG. 2 short-circuits the planar conductor 12 and the planar conductor 13 at a radio frequency, so that the planar conductor 12 and the planar conductor 13 are short-circuited at the short-circuit point 143. (In FIG. 4, the open-ended wire 22 in the short-circuited state is not shown). Note that FIG. 5 is a diagram showing an example of a normal monopole structure without a slit and an open-ended line.

Therefore, the antenna device according to the present embodiment can be equivalently regarded as a folded monopole structure.

When the folded monopole structure is used, the input impedance real part of the antenna can be made higher than that of the normal monopole structure shown in FIG. 5 as an example. This is because the current of the wireless terminal 1 is distributed to the short-circuit point 143 and the feeding current becomes small.

Further, in the antenna device of FIG. 2, the actual input impedance portion of the antenna can be controlled by changing the position of the slit 16 in the left-right direction (that is, the ± x direction of FIG. 2).

When the slit 16 is moved to the left (that is, the + x direction in FIG. 2), the impedance real part becomes high, and when it is moved to the right (that is, the −x direction in FIG. 2), the impedance real part becomes low. Therefore, impedance matching can be achieved by adjusting the position of the slit 16.

An example of the calculation result is shown below. In the antenna device according to the present embodiment, when H = 0.17 wavelength and L = 0.17 wavelength at f ₀ , the calculation is performed using the finite element method. Here, the width of the plane conductor 12 is f ₀ and La = 0.25 wavelength.

FIG. 6 is a diagram showing a calculation result of the input impedance seen from the wireless terminal 1 of the antenna device according to the embodiment. Here, the normalized impedance is 50Ω.

Referring to FIG. 6, the volume standing wave ratio (VSWR) is 2 or less in the frequency band used (that is, the band including f _l , f ₀ , and f _h ). That is, it can be confirmed that impedance matching is achieved.

FIG. 7 is a diagram showing the calculation result of the radiation pattern of the antenna device according to the embodiment in the horizontal _plane of vertically polarized waves (that is, the xy plane of FIG. 2). Further, FIG. 8 is a diagram showing the calculation result of the radiation pattern of the antenna device according to the embodiment in the horizontal plane of vertical polarization in _fh (that is, the xy plane of FIG. 2).

The calculation result of the antenna device in FIG. 1 is shown in FIG. 1 when H = 0.18 wavelength and L = 0.25 wavelength at _f0 .

Referring to FIGS. 7 and 8, the configuration of the antenna device according to the present embodiment in FIG. 2 has improved the gain in the horizontal _plane at _f and f as compared with the case of the antenna device in FIG. Can be confirmed.

The shape of the flat conductor 12 is not limited to the shape shown in the present embodiment. However, when the size of the flat conductor 12 is increased, the capacitance between the plane conductor 12 and the overhead wire 101 becomes large, so that the overhead wire detection voltage can be increased.

Further, the shape of the planar conductor 13 is not limited to the shape shown in the present embodiment. The plane conductor 13 may have a height sufficient to provide the connection point 46. For example, the planar conductor 13 may have a height of 0.01 wavelength at _f0 .

The shape of the substrate 11 may be any shape as long as the flat conductor 12 and the flat conductor 13 can be formed on the back surface of the substrate 11. However, the shape of the substrate 11 needs to be such that the volume of the wind noise is equal to or less than a desired value.

Further, in a normal monopole structure, as the height H of the antenna decreases, the actual part of the input impedance of the antenna decreases. Therefore, impedance matching becomes difficult.

Therefore, the configuration of the antenna device according to the present embodiment is particularly effective when the height H of the antenna is f ₀ and is lower than 0.2 wavelength.

The width of the open-ended line 21, the width of the open-ended line 22, the width of the short-circuited line 31, and the width of the short-circuited line 32 are not limited to the embodiments shown in the present embodiment. However, for example, the characteristic impedance of the line can be set to a width of 50Ω.

Further, the crawling path of the tip open line 21, the tip open line 22, the tip short-circuit line 31, and the tip short-circuit line 32 is not limited to the embodiment shown in the present embodiment. However, the path may be bent in the middle so that it can be formed on the surface of the substrate 11, for example.

As described above, the antenna device includes the columnar conductor 6, the substrate 11, the flat conductor 12, the flat conductor 13, the slit 16, the open tip line 21, the open tip line 22, the short circuit line 31, and the tip. By providing the short-circuit line 32, it is possible to obtain a small antenna for overhead wire voltage detection and wireless communication, which has a small wind noise, a high horizontal gain, and a small size.

<Second embodiment>
An antenna device and a railroad vehicle according to the present embodiment will be described. In the following description, components similar to the components described in the above-described embodiments will be illustrated with the same reference numerals, and detailed description thereof will be omitted as appropriate. ..

<About the configuration of the antenna device>
In the present embodiment, the configuration when the tip open line 23 and the tip short circuit line 33 are further added to the antenna device according to the first embodiment will be described.

FIG. 9 is a diagram schematically showing an example of the configuration of the antenna device according to the present embodiment. Further, FIG. 10 is a diagram showing an example of an equivalent circuit at the radio frequency of the antenna device according to the present embodiment.

Further, FIG. 11 is a diagram showing a calculation result of the input impedance seen from the wireless terminal of the antenna device according to the present embodiment.

As an example shown in FIG. 9, the antenna device according to the present embodiment includes a wireless terminal 1, an overhead wire voltage detection terminal 2, a columnar conductor 6, a substrate 11, a flat conductor 12, a flat conductor 13, and a slit. 16, tip open line 21, tip open line 22, tip open line 23, tip short circuit line 31, tip short circuit line 32, tip short circuit line 33, short circuit point 41, short circuit point 42, short circuit. It includes a point 43, a connection point 46, a ground conductor plate 51, and a connection conductor 61.

The tip open line 23 and the tip short circuit line 33 are formed on the surface of the substrate 11 (that is, the surface on the front side of the paper surface in FIG. 9).

The tip open line 23 and the tip short circuit line 33 are arranged at positions corresponding to the plane conductor 13 in a plan view. The open-ended line 23 and the short-circuited-tip line 33 are transmission lines with the flat conductor 13 as the ground.

One end of the open-ended line 23 is connected to the open-ended line 21, and one end of the short-circuited line 33 is connected to the open-ended line 21.

On the other hand, the other end of the open-ended line 23 is an open end arranged at a position overlapping the flat conductor 13 in a plan view. Further, the other end of the tip short-circuit line 33 is short-circuited to the flat conductor 13 by the short-circuit point 43.

FIG. 10 is a diagram showing an example of an equivalent circuit at a radio frequency of the antenna device according to the present embodiment. The resonance of the planar conductor 12 can be regarded as the series resonance circuit 201 including the capacitance 202, the inductance 203, and the resistance 204 in FIG.

When the electrical length of the open-ended line 23 is 1/4 wavelength or less, the open-ended line 23 operates as a capacitance 212 connected in parallel to the open-ended line 21.

When the electrical length of the tip short-circuit line 33 is 1/4 wavelength or less, the tip short-circuit line 33 operates as an inductance 213 connected in parallel to the tip open line 21.

Therefore, the open-ended line 23 and the short-circuited short-circuit line 33 can be regarded as a parallel resonant circuit 211 connected in parallel to the open-ended line 21.

In the equivalent circuit of FIG. 10, if the resonance frequency of the parallel resonant circuit 211 is f ₀ , the capacitance 212 is _{Cr, and the inductance 213 is L r ,} f ₀ can be shown as follows.

In the above equation, since f ₀ is predetermined, L _r can be obtained by determining C _r . If _Cr is adjusted, the Q value of the parallel resonance circuit 211 changes, and the input impedance of the antenna can be widened as a double resonance.

Further, by adjusting the length of the open-ended line 23 and the width of the open-ended line 23 (that is, the characteristic impedance), the desired capacitance 212 can be realized at the radio frequency.

Similarly, by adjusting the length of the tip short circuit line 33 and the width of the tip short circuit line 33 (that is, the characteristic impedance), the desired inductance 213 at the radio frequency can be realized.

FIG. 11 is a diagram showing a calculation result of the input impedance seen from the wireless terminal 1. In the antenna device shown in FIG. 9, H = 0.17 wavelength, L = 0.17 wavelength, La = 0.25 wavelength, and the normalized impedance of 50Ω at _f0 .

With reference to FIG. 11, it can be confirmed that the impedance locus has a kink (that is, a knot-shaped locus) and the input impedance is widened.

Further, as compared with the case of the antenna device having no tip open line 23 and tip short circuit line 33 shown in FIG. 6, in the frequency band used (that is, the band including f _l , f ₀ and f _h ). , VSWR is improved.

The crawling path of the tip open line 23 and the tip short circuit line 33 is not limited to the embodiment shown in the present embodiment. That is, for example, the path may be bent in the middle so that it can be formed on the surface of the substrate 11.

Further, the shape of the planar conductor 13 is not limited to the shape shown in the present embodiment. The flat conductor 13 may have a height such that the open-ended line 23, the short-circuited line 33, and the connection point 46 are provided. For example, the planar conductor 13 may have a height of 0.01 wavelength at _f0 .

As described above, the antenna device includes the columnar conductor 6, the substrate 11, the flat conductor 12, the flat conductor 13, the slit 16, the open-ended line 21, the open-ended line 22, the open-ended line 23, and the tip. By providing the short-circuit line 31, the tip short-circuit line 32, and the tip short-circuit line 33, the wind noise is small, the horizontal gain is high, the wide band is supported, and the overhead line voltage detection and wireless are small. A shared antenna for communication can be obtained.

<Third embodiment>
An antenna device and a railroad vehicle according to the present embodiment will be described. In the following description, components similar to the components described in the above-described embodiments will be illustrated with the same reference numerals, and detailed description thereof will be omitted as appropriate. ..

<About the configuration of the antenna device>
In the present embodiment, in the antenna device according to the second embodiment, the configuration in which the tip short-circuit line 31 and the tip short-circuit line 32 are deleted and the spiral conductor 81 and the spiral conductor 82 are provided instead will be described.

FIG. 12 is a diagram schematically showing an example of the configuration of the antenna device according to the present embodiment.

As an example shown in FIG. 12, the antenna device according to the present embodiment includes a wireless terminal 1, an overhead wire voltage detection terminal 2, a columnar conductor 6, a substrate 11, a flat conductor 12, a flat conductor 13, and a slit. 16, tip open line 21, tip open line 22, tip open line 23, tip short circuit line 33, short circuit point 43, connection point 46, ground conductor plate 51, connection conductor 61, and plan view. The spiral conductor 81, which is a spiral conductor, and the spiral conductor 82, which is a spiral conductor in a plan view, are provided.

The spiral conductor 81 and the spiral conductor 82 are formed on the surface of the substrate 11 (that is, the surface on the front side of the paper surface in FIG. 12).

The spiral conductor 81 is formed in the vicinity of the overhead wire voltage detection terminal 2. The overhead wire voltage detection terminal 2 is arranged between one end of the spiral conductor 81 and the ground conductor plate 51. The other end of the spiral conductor 81 is connected to the flat conductor 12.

The spiral conductor 82 is formed in the vicinity of the columnar conductor 6. One end of the spiral conductor 82 is connected to the columnar conductor 6 via the connecting conductor 61. The other end of the spiral conductor 82 is connected to the flat conductor 12.

The spiral conductor 81 and the spiral conductor 82 operate as an inductance. The spiral conductor 81 conducts the overhead wire voltage detection terminal 2 and the flat conductor 12 at the overhead wire power supply frequency and cuts off at the radio frequency. The spiral conductor 82 conducts the planar conductor 12 and the columnar conductor 6 at the overhead wire power supply frequency and interrupts them at the radio frequency.

For example, in FIG. 9, not only a reverse-phase current but also a small amount of in-phase current flows through the tip-short-circuit line 31 and the tip-short-circuit line 32 on the surface of the substrate 11 and the flat conductor 12 on the back surface of the substrate 11. Therefore, the current cutoff performance at the radio frequency is not sufficient.

On the other hand, in the present embodiment, the spiral conductor 81 and the spiral conductor 82 are provided instead of the tip short-circuit line 31 and the tip short-circuit line 32.

For example, when the size of the spiral conductor 81 and the size of the spiral conductor 82 are 20.4 mm × 20.4 mm and the number of turns is 14, the inductance is 2.4 μH.

When the frequency of the overhead wire power supply is 60 Hz and the center frequency of the radio frequency band is 160 MHz, the reactance of the spiral conductor 81 and the reactance of the spiral conductor 82 are 0.9 mΩ at 60 Hz and 2.4 kΩ at 160 MHz, respectively. Become.

Therefore, at 60 Hz, the reactance of the spiral conductor 81 and the reactance of the spiral conductor 82 are negligibly small, while at 160 MHz, they can be regarded as almost open.

As described above, by providing the spiral conductor 81 and the spiral conductor 82 in place of the tip short-circuit line 31 and the tip short-circuit line 32, the current cutoff performance at the radio frequency can be improved.

As a result, the high-frequency current flowing from the flat conductor 12 to the overhead wire voltage detection terminal 2 and the columnar conductor 6 can be sufficiently cut off, so that the horizontal gain at the radio frequency can be improved.

The spiral conductor 81 and the spiral conductor 82 are formed on either the front surface of the substrate 11 (that is, the surface on the front side of the paper surface in FIG. 12) or the back surface (that is, the surface on the back side of the paper surface in FIG. 12). It may be formed on both sides of the substrate 11.

Further, the shape of the spiral conductor 81 and the shape of the spiral conductor 82 are not limited to the embodiments shown in the present embodiment, and for example, a square or a circular shape is assumed as the outer shape thereof.

Further, the size and the number of turns of each of the spiral conductor 81 and the spiral conductor 82 are adjusted so that the reactance is so small that it can be ignored at the overhead wire power supply frequency and can be regarded as almost open at the radio frequency.

Further, when the spiral conductor 81 and the spiral conductor 82 are formed on the front surface of the substrate 11, no conductor is formed on the back surface of the substrate 11 in a portion where the spiral conductor 81 and the spiral conductor 82 are present in a plan view. Is desirable. Similarly, when the spiral conductor 81 and the spiral conductor 82 are formed on the back surface of the substrate 11, no conductor is formed on the front surface of the substrate 11 in a portion of the spiral conductor 81 and the spiral conductor 82 in a plan view. Is desirable. This is because the inductance decreases when another conductor is in close proximity to the spiral conductor 81 and the spiral conductor 82.

As described above, the antenna device includes the columnar conductor 6, the substrate 11, the flat conductor 12, the flat conductor 13, the slit 16, the open tip line 21, the open tip line 22, the open tip line 23, and the tip. By providing the short-circuit line 33, the spiral conductor 81, and the spiral conductor 82, the wind noise is small, the horizontal gain is high, the wide band is supported, and the overhead line voltage detection and radio are small. A shared antenna for communication can be obtained.

The spiral conductor 81 and the spiral conductor 82 may be provided in place of the tip short-circuit line 31 and the tip short-circuit line 32 in FIG. 2, for example.

<Effects caused by the above-described embodiments>
Next, an example of the effect caused by the above-described embodiment will be shown. In the following description, the effect is described based on the specific configuration shown in the embodiment described above, but to the extent that the same effect occurs, the examples are described in the present specification. May be replaced with other specific configurations indicated by.

Further, the replacement may be made across a plurality of embodiments. That is, it may be the case that the respective configurations shown in the examples in different embodiments are combined to produce the same effect.

According to the embodiment described above, the antenna device includes the ground conductor plate 51, the substrate 11, the first flat conductor, the second flat conductor, the columnar conductor 6, and the first open tip. It includes a line, a first tip short-circuit line, a second tip short-circuit line, and a second tip open line. Here, the first planar conductor corresponds to, for example, the planar conductor 12. Further, the second planar conductor corresponds to, for example, the planar conductor 13. Further, the first open-ended line corresponds to, for example, the open-ended line 21. Further, the first short-circuited line at the tip corresponds to, for example, at least one of the short-circuited line 31 at the tip and the spiral conductor 81. The second tip short-circuit line corresponds to, for example, at least one of the tip short-circuit line 32 and the spiral conductor 82. Further, the second open-ended line corresponds to, for example, the open-ended line 22. The substrate 11 is connected to the ground conductor plate 51. The planar conductor 12 is formed on the first surface of the substrate 11 (for example, the back surface of the substrate 11). Further, the flat conductor 12 is located on the side opposite to the end portion connected to the ground conductor plate 51 of the substrate 11. The plane conductor 13 is formed on the first surface of the substrate 11 (for example, the back surface of the substrate 11). Further, the flat conductor 13 is separated from the flat conductor 12 and comes into contact with the ground conductor plate 51. The columnar conductor 6 is arranged on the side of the substrate 11 opposite to the end portion connected to the ground conductor plate 51. The open-ended line 21 is formed on a second surface (for example, the surface of the substrate 11) which is a surface opposite to the first surface of the substrate 11. Further, in the open-ended line 21, the first end is connected to the ground conductor plate 51 via the wireless terminal 1, and the second end, which is the end opposite to the first end, is It is an open end arranged at a position overlapping the plane conductor 12 in a plan view. The tip short-circuit line 31 is formed on the second surface of the substrate 11 (for example, the surface of the substrate 11). Further, the tip short-circuit line 31 has a third end connected to the ground conductor plate 51 via the overhead wire voltage detection terminal 2, and is a fourth end which is an end opposite to the third end. The portion is a short-circuit end short-circuited with the flat conductor 12. Here, the fourth end corresponds to, for example, the short circuit point 41. The tip short-circuit line 32 is formed on the second surface of the substrate 11 (for example, the surface of the substrate 11). Further, in the tip short-circuit line 32, the fifth end is connected to the columnar conductor 6 via the connecting conductor 61, and the sixth end, which is the end opposite to the fifth end, is a flat surface. It is a short-circuit end that short-circuits with the conductor 12. Here, the sixth end corresponds to, for example, the short circuit point 42. The open-ended line 22 is formed on the second surface of the substrate 11 (for example, the surface of the substrate 11). Further, in the open-ended line 22, the seventh end is connected to the flat conductor 13, and the eighth end, which is the end opposite to the seventh end, is connected to the flat conductor 12 in a plan view. It is an open end arranged at an overlapping position. Here, the seventh end corresponds to, for example, the connection point 46. When the area for separating the plane conductor 12 and the plane conductor 13 and the separation area 100 are set, a slit 16 extending from the separation region 100 toward the columnar conductor 6 is formed in the plane conductor 12. The slit 16 is formed at a position sandwiched between the open-ended line 21 and the open-ended line 22 in a plan view.

According to such a configuration, the slit 16 is formed at a position sandwiched between the open-ended line 21 and the open-ended line 22 in a plan view, so that the length of the columnar conductor 6 is short and the size is small. Even with an antenna device, wind noise can be suppressed and the horizontal gain can be increased.

In addition to these configurations, other configurations shown in the present specification may be omitted as appropriate. That is, at least if these configurations are provided, the effects described above can be produced.

However, the present specification is not mentioned when at least one of the other configurations shown in the present specification is appropriately added to the above-described configuration, that is, as the above-described configuration. Similar effects can be produced even if other configurations, for example, are added as appropriate.

Further, according to the embodiment described above, when the signal of the first frequency (for example, the overhead wire power supply frequency) is input, the open-ended line 21 and the open-ended line 22 are cut off and the open-ended line 22 is cut off. The tip short-circuit line 31 and the tip short-circuit line 32 are conductive. Further, when a signal having a second frequency (for example, a radio frequency) higher than the first frequency is input, the open-ended line 21 and the open-ended line 22 are conducted and the short-circuited-ended line is connected. 31 and the tip short-circuit line 32 are cut off. According to such a configuration, when a signal of the frequency of the overhead wire power supply is input, the overhead wire voltage can be detected. Further, when a signal having a frequency of a wireless signal is input, wireless communication can be performed.

Further, according to the embodiment described above, the spiral conductor 81 and the spiral conductor 82 have a spiral shape in a plan view. The spiral conductor 81 is located in the vicinity of the overhead wire voltage detection terminal 2. Further, the spiral conductor 82 is located in the vicinity of the connecting conductor 61. According to such a configuration, the current cutoff performance at the radio frequency can be improved. As a result, the high-frequency current flowing from the flat conductor 12 to the overhead wire voltage detection terminal 2 and the columnar conductor 6 can be sufficiently cut off, so that the horizontal gain at the radio frequency can be improved.

Further, according to the embodiment described above, the antenna device includes a third tip short-circuit line and a third tip open line. Here, the third tip short-circuit line corresponds to, for example, the tip short-circuit line 33. Further, the third open-ended line corresponds to, for example, the open-ended line 23. The tip short-circuit line 33 is formed on the second surface of the substrate 11 (for example, the surface of the substrate 11). Further, in the tip short-circuit line 33, the ninth end is connected to the tip open line 21, and the tenth end, which is the end opposite to the ninth end, is short-circuited with the flat conductor 13. It is a short-circuit end. Here, the tenth end corresponds to, for example, the short circuit point 43. The open-ended line 23 is formed on the second surface of the substrate 11 (for example, the surface of the substrate 11). Further, in the open-ended line 23, the eleventh end is connected to the open-ended line 21, and the twelfth end, which is the end opposite to the eleventh end, is a flat conductor 13 in a plan view. It is an open end arranged at a position overlapping with. According to such a configuration, in particular, if the series resonance circuit 201 and the parallel resonance circuit 211 are used and adjusted so as to have double resonance, the input impedance of the antenna can be widened.

Further, according to the embodiment described above, the length of the columnar conductor 6 is 0.2 wavelength or less at the second frequency. According to such a configuration, the amount of electromagnetic field coupling between the planar conductor 12 and the columnar conductor 6 can be suppressed. By doing so, the high frequency current flowing through the columnar conductor 6 can be reduced.

Further, according to the embodiment described above, the distance between the columnar conductor 6 and the ground conductor plate 51 is 0.2 wavelength or less at the second frequency. According to such a configuration, impedance matching can be realized while downsizing the antenna device.

Further, according to the embodiment described above, the railroad vehicle includes the above-mentioned antenna device. According to such a configuration, even when the length of the columnar conductor is shortened in order to suppress the wind noise and increase the horizontal gain, the impedance can be appropriately matched.

<About the modified example in the embodiment described above>
In the embodiments described above, the materials, materials, dimensions, shapes, relative arrangement relationships, implementation conditions, etc. of each component may also be described, but these are one example in all aspects. However, it is not limited to those described in the present specification.

Therefore, innumerable variations and equivalents for which examples are not shown are envisioned within the scope of the techniques disclosed herein. For example, transforming, adding or omitting at least one component, or extracting at least one component in at least one embodiment and combining it with the components of another embodiment. Shall be included.

Further, as long as there is no contradiction, the components described as being provided with "one" in the above-described embodiment may be provided with "one or more".

Furthermore, each component in the embodiments described above is a conceptual unit, and within the scope of the technique disclosed herein, one component comprises a plurality of structures. It is assumed that one component corresponds to a part of a structure, and further, a case where a plurality of components are provided in one structure is included.

In addition, each component in the above-described embodiment shall include a structure having another structure or shape as long as it exhibits the same function.

In addition, the description in the present specification is referred to for all purposes relating to the present technology, and none of them is recognized as a prior art.

Further, in the above-described embodiment, when the material name or the like is described without being specified, the material contains other additives, for example, an alloy or the like, as long as there is no contradiction. It shall be included.

1 Wireless terminal, 2 Overhead voltage detection terminal, 6 Columnar conductor, 11 Substrate, 12, 12a, 13 Flat conductor, 16 Slit, 21, 22, 23 Tip open line, 31, 31a, 32, 33 Tip short circuit line, 41, 42,43,143 Short circuit point, 46 connection point, 51 ground conductor plate, 61 connection conductor, 71 capacitance, 81,82 spiral conductor, 100 separation region, 101 overhead wire, 201 series resonance circuit, 202,212 capacitance, 203, 213 inductance, 204 resistance, 211 parallel resonance circuit.

Claims (7)

With a ground conductor plate,
A substrate connected to the ground conductor plate and
A first planar conductor formed on the first surface of the substrate and located on the side opposite to the end connected to the ground conductor plate of the substrate.
A second planar conductor formed on the first surface of the substrate, separated from the first planar conductor, and in contact with the ground conductor plate.
A columnar conductor arranged on the side of the substrate opposite to the end connected to the ground conductor plate,
It is formed on a second surface of the substrate opposite to the first surface, the first end is connected to the ground conductor plate via a wireless terminal, and the first end. A first open end line, which is an open end in which the second end, which is the end opposite to the portion, is arranged at a position where it overlaps with the first planar conductor in a plan view.
It is formed on the second surface of the substrate, the third end is connected to the ground conductor plate via the overhead wire voltage detection terminal, and the end is opposite to the third end. A first tip short-circuit line, the fourth end of which is a short-circuit end short-circuited with the first planar conductor.
A sixth, which is formed on the second surface of the substrate, has a fifth end connected to the columnar conductor via a connecting conductor, and is an end opposite to the fifth end. A second tip short-circuit line, the end of which is a short-circuit end that short-circuits with the first planar conductor.
An eighth end formed on the second surface of the substrate, the seventh end of which is connected to the second planar conductor, and the end opposite to the seventh end. Is provided with a second tip open line, which is an open end arranged at a position overlapping the first planar conductor in a plan view.
The region that separates the first planar conductor and the second planar conductor is defined as a separation region.
The first planar conductor is formed with a slit extending from the separated region toward the columnar conductor.
The slit is formed at a position sandwiched between the first open-ended line and the second open-ended line in a plan view.
Antenna device. When a signal of the first frequency is input, the first open-ended line and the second open-ended line are cut off, and the first short-circuited line and the second tip are cut off. The short circuit line is conducting,
When a signal of a second frequency, which is a frequency higher than the first frequency, is input, the first open-ended line and the second open-ended line are conductive and the first open line is connected. The tip short-circuit line and the second tip short-circuit line are cut off.
The antenna device according to claim 1. The first tip short-circuit line and the second tip short-circuit line have a spiral shape in a plan view.
The first short-circuit line at the tip is located in the vicinity of the overhead line voltage detection terminal.
The second short-circuit line at the tip is located in the vicinity of the connecting conductor.
The antenna device according to claim 1 or 2. A tenth end formed on the second surface of the substrate, the ninth end being connected to the first open-circuit line, and the end opposite to the ninth end. A third tip short-circuit line, the portion of which is a short-circuit end short-circuited with the second flat conductor,
A twelfth end formed on the second surface of the substrate, the eleventh end being connected to the first open-ended line, and the end opposite to the eleventh end. A third open end line, which is an open end arranged at a position where the portion overlaps with the second planar conductor in a plan view, is further provided.
The antenna device according to any one of claims 1 to 3. The length of the columnar conductor is 0.2 wavelength or less at the second frequency.
The antenna device according to claim 2. The distance between the columnar conductor and the ground conductor plate is 0.2 wavelength or less at the second frequency.
The antenna device according to claim 2 or 5. The antenna device according to any one of claims 1 to 6 is provided.
Railroad vehicle.

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