JP2003347838A - Antenna device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an antenna device, capable of receiving both circularly polarized signal of satellite wave and a linearly polarized signal of a ground wave, and of being installed with a small height. <P>SOLUTION: An antenna portion 12 for a satellite wave is disposed at the front surface of a ceramic substrate 10, and an antenna portion 14 for a ground wave constituted by a large plate is installed on the rear surface to be contacted thereto. A ground plate 18 constituted by a larger plate is disposed in parallel on the rear surface side and spaced apart by a predetermined distance from the antenna portion 14 for the terrestrial wave, and is interposed shorting pins 20 for shorting between the central part of the edge of the antenna portion 14 for the terrestrial wave and the earth plate 18 to be electrically shorted therebetween and to be supported with each other. An external conductor 16b of a coaxial cable 16 for transmitting the satellite wave is electrically connected to the antenna portion 14 for the terrestrial wave, and a central conductor 16a of the cable is passed through the ceramic substrate 10, to be electrically connected to the offset feed position of the antenna portion 12 for the satellite wave. A vertical element portion 24 for the terrestrial wave is passed through the ground plate in isolated state to be electrically connected to the central position of the antenna portion 14 for the terrestrial wave. <P>COPYRIGHT: (C)2004,JPO

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna apparatus for receiving both a circularly polarized signal from a satellite and a terrestrial linearly polarized signal retransmitted by a repeater receiving the signal.

[0002]

2. Description of the Related Art In recent years, broadcasting such as S-BAND (Sirius radio and XM radio) has been planned in the United States. For example, in Sirius radio, a circularly polarized signal of 2320 to 2332.5 MHz is transmitted from a broadcasting satellite, and this satellite wave is received by a repeater on the ground, and 2323.7 to 2328.8 MHz is transmitted as a terrestrial wave. Is a broadcasting system in which a linearly polarized signal is retransmitted. In the XM radio, 2332 to 233 are used as satellite waves and terrestrial waves.
This is a broadcasting system in which signals are transmitted in a frequency band of 8.75 MHz. In these systems, an area such as a highway where a circularly polarized signal from a satellite is blocked by a large building or the like is covered by a linearly polarized ground wave signal from a repeater.

[0003]

Conventionally, in order to receive such a broadcast by a vehicle, an antenna device for receiving a circularly polarized signal from a satellite and an antenna device for receiving a linearly polarized signal of a terrestrial wave are used. Two had to be installed in each. In addition, a pole antenna having a low elevation angle gain and a high pole antenna is often used as an antenna device for receiving a terrestrial linearly polarized signal. Therefore, when the antenna device of the pole antenna is provided, it protrudes high from the vehicle, and two separate antenna devices are provided, so that the appearance of the vehicle is impaired.

SUMMARY OF THE INVENTION The present invention has been made to solve such a conventional problem. An antenna device for receiving a circularly polarized signal from a satellite and an antenna device for receiving a terrestrial linearly polarized signal from a repeater are integrated. It is another object of the present invention to provide an antenna device having a low height provided.

[0005]

In order to achieve the above object, an antenna device according to the present invention comprises a satellite wave antenna portion provided on the surface of a dielectric substrate, and abutting against the back surface of the dielectric substrate to form the dielectric material. A ground wave antenna portion made of a plate material larger than the outer shape of the substrate is provided, and a ground made of a plate material larger than the outer shape of the terrestrial antenna portion is provided on the back side of the dielectric substrate at a predetermined distance from and parallel to the terrestrial antenna portion. A plate is disposed, a short pin is interposed between the side of the terrestrial antenna unit and the ground plate, and an outer conductor of the coaxial cable for transmitting satellite waves is electrically connected to the terrestrial antenna unit and a center conductor is provided. Is electrically connected to the satellite wave antenna section through the dielectric substrate, and the ground wave vertical element section is passed through the ground plate in an insulated state, and the terrestrial antenna section is Electrically connected to receive circularly polarized signals from satellites in the satellite wave antenna portion is configured to receive a terrestrial linear polarization signal in the terrestrial antenna unit.

The satellite wave antenna section is a rectangular patch antenna, and the center conductor of the satellite wave transmitting coaxial cable is electrically connected to an offset feeding position of the rectangular patch antenna, and the terrestrial wave antenna section has a rectangular shape. Yes,
The terrestrial vertical element section may be electrically connected to the center position.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a plan view of an embodiment of the antenna device of the present invention. FIG. 2 is a front view of FIG. FIG. 3 is a sectional view taken along the line AA of FIG. FIG. 4 is a vertical cross-sectional view of the antenna device of FIG. 1 in a state where the antenna device is housed in the case. FIG. 5 is a graph showing gain characteristics of the E plane with respect to satellite waves. FIG. 6 is a graph showing gain characteristics of the E-plane with respect to terrestrial waves. FIG. 7 shows H for ground waves.
FIG. 4 is a diagram illustrating gain characteristics of a surface.

In FIGS. 1 to 3, a satellite wave antenna section 12 which is a rectangular patch antenna having a size smaller than the outer shape of the ceramic substrate 10 is electrically conductive on the surface of a ceramic substrate 10 as a dielectric substrate having a square planar shape. It is appropriately disposed by printing a thin film or the like. The terrestrial antenna unit 14 is provided in contact with the back surface of the ceramic substrate 10 and made of a plate material and having a rectangular plane larger than the outer shape of the ceramic substrate 10. The terrestrial antenna unit 14 is formed by appropriately plating a conductive plate with a good conductive material. Then, the center conductor 16a of the satellite wave transmitting coaxial cable 16 penetrates the ceramic substrate 10 from the terrestrial wave antenna unit 14 side and is electrically connected to the offset power supply position of the satellite wave antenna unit 12 by soldering or the like. The center conductor 16a is, of course, electrically insulated from the terrestrial antenna unit 14. Further, the outer conductor 16b of the satellite wave transmitting coaxial cable 16 is electrically connected to the terrestrial antenna unit 14 by soldering or the like, is further routed to the center of one side of the terrestrial antenna unit 14, and is soldered to that side. Fixed. Here, the satellite wave antenna unit 12 and the terrestrial wave antenna unit 14 are disposed in parallel via the ceramic substrate 10, and a patch antenna for receiving a satellite wave is formed to receive a circularly polarized signal of the satellite wave. . In this patch antenna, the terrestrial antenna unit 14 functions as a ground plate.

On the back side of the ceramic substrate 10, an earth plate 18 made of a plate material having a rectangular plane larger than the outer shape of the terrestrial antenna unit 14 is disposed in parallel with the terrestrial antenna unit 14 at a predetermined interval. You. The earth plate 18 is formed by plating a suitable good conductive material on a conductive plate. One end of each of the short pins 20, 20, 20 is soldered in a vertical position to the center of the three sides other than the outer conductor 16b of the satellite wave transmitting coaxial cable 16 of the terrestrial antenna unit 14 to which the outer conductor 16b is soldered. The other ends of the short pins 20, 20, 20 are fixed and electrically connected to the ground plate 18 by soldering or the like. An external conductor 16 is connected to one side of the terrestrial antenna unit 14.
The satellite wave transmitting coaxial cable 16 to which b is fixed is bent so as to hang down from the side thereof and penetrates through the earth plate 18.
Are fixed and electrically connected to the earth plate 18 by soldering or the like. Further, insulating support members 22, 22, 22 having a substantially columnar outer shape are interposed between the terrestrial antenna unit 14 and the earth plate 18 so as to surround the short pins 20, 20, 20, and the ground wave antenna unit 14 and the ground. The space between the plates 18 is maintained at a predetermined interval. And the vertical element part 24 for terrestrial waves
The terrestrial antenna unit 14 is electrically connected to the square center position of the terrestrial antenna unit 14 by soldering or the like by penetrating through the earth plate 18 from the opposite side (the back side of the earth plate 18). The ground wave vertical element portion 24 is, of course, electrically insulated from the ground plate 18. Here, the terrestrial antenna unit 14 and the earth plate 1
8 are arranged in parallel at predetermined intervals, and a patch antenna for receiving terrestrial waves is formed using the air within the predetermined intervals as a dielectric layer to receive a terrestrial linearly polarized signal.

Further, as shown in FIG. 4, a circuit board (not shown) is provided behind the ground plate 18, and a shield cover 28 is provided so as to cover the circuit board. The circuit board includes a low noise amplifier that amplifies a circularly polarized signal of a satellite wave received by the satellite wave antenna unit 12 and a low noise amplifier that amplifies a linearly polarized signal of a terrestrial wave received by the terrestrial antenna unit 14, The shield cover 28 is configured so that its position is divided and mounted, and shields the two low-noise amplifiers separately.

Then, the antenna device having such a configuration is housed in the flat case 30. The case 30 can be divided into upper and lower parts of a case base 30a and a case lid 30b. The case lid 30b that covers the front of the antenna device is made of a dielectric resin having an appropriate dielectric constant and functions as a radome. Also, magnets 32, 32 are provided on the case base 30a.
And a double-sided tape 34 is disposed on the entire bottom surface of the case base 30a. The double-sided tape 34 is easily and appropriately fixed to the roof 36 of the vehicle by the magnetic attraction of the magnets 32 and the adhesive force of the double-sided tape 34. Can be done.

The measurement results of the antenna characteristics of the antenna device of the present invention as described above were as follows. In the antenna device of the present invention to be measured, the ceramic substrate 10 has 30
mm square with a thickness of 4 mm and a dielectric constant of about 8
It is. The satellite wave antenna section 12 is 23 mm on a side due to the conductive thin film, and its electrical length is set to a half wavelength of 2338.75 MHz of the measurement frequency signal to be received. The terrestrial antenna unit 14 has a conductive metal plate having a thickness of 0.3 mm and both sides thereof are plated with good conductive material such as gold, and is a square having a side of 42 mm. Further, the ground plate 18 is a square having a side of 65 mm and a conductive metal plate having good conductive plating such as gold on both surfaces. 5 mm between the terrestrial antenna unit 14 and the earth plate 18
And the short pins 20, 20, 20 are wires having a thickness of 0.5 mm. Moreover, the outer conductor 16b
The outer conductor 16b of the coaxial cable 16 for transmitting satellite waves, which also functions as a short pin, has an outer shape of 0.5 mm. The measurement result was 2338.75 as shown in FIG.
The antenna gain on the E-plane for a circularly polarized signal of a satellite wave of MHz shows a high gain of 3 dB or more, which is larger than 2 dB required for performance, at an elevation angle of 20 ° or more. As shown in FIG. 6, the antenna gain of the E plane with respect to the linearly polarized signal of the ground wave of 2338.75 MHz is:
At an elevation angle of 0 °, the gain is approximately −0.05 dB, which is larger than −1 dB required for performance, and a high gain is exhibited at a low elevation angle. As shown in FIG. 7, the antenna gain on the H plane with respect to the terrestrial linearly polarized signal is omnidirectional.

Therefore, the antenna device of the present invention has good antenna characteristics for both satellite waves and terrestrial waves, and is suitable as an antenna for S-BAND broadcasting and the like. Here, the satellite wave antenna unit 12 acts as a circularly polarized patch antenna for the satellite wave, and the ground wave antenna unit 14 has a short pin 20 at the center of each side for the ground wave.
The terrestrial vertical element 24 is electrically connected to the center position of the terrestrial vertical element 24 so as to operate as an M-type antenna, and the terrestrial vertical element 24 serves as a small monopole antenna. It is considered that the directional characteristics in the horizontal direction are improved by acting. In the antenna device of the present invention, the height from the satellite wave antenna section 12 to the ground plate 18 is extremely thin, about 10 mm, and the height of the case 30 for housing the antenna apparatus can be set to about 24 mm. Was. For this reason, even if the antenna device of the present invention is installed on the roof of a vehicle or the like, the appearance is not impaired. By the way, the short pins 20, 20, 20 and the outer conductor 16b of the satellite wave transmitting coaxial cable 16 acting as a short pin are:
In the above embodiment, the terrestrial antenna unit 14 and the earth plate 18 are fixed and electrically connected to each other by soldering. At the time of this soldering, the objects are the terrestrial antenna unit 14 made of a conductive plate material and the ground plate 18, and the work is more complicated than soldering to a conductive thin film provided by printing or the like on a dielectric substrate. Can be done easily and reliably.

In the above-described embodiment, the satellite wave antenna section 12 is configured as a circularly polarized wave receiving antenna by feeding offset power to a square patch antenna. However, the present invention is not limited to this structure as long as a circularly polarized wave can be received. One of the patch antennas may be cut out at one corner to supply power to the center, or a circular patch antenna may be provided with cutouts at opposite positions at both ends of the diameter to supply power to the center. Also, the terrestrial antenna unit 14 is not limited to a square, but may be a circle, or may be a type in which a feeding point is offset from the center and offset feeding is performed. Although the ceramic substrate 10 having a high dielectric constant is used as the dielectric substrate and the external dimensions of the satellite wave antenna section 12 are small, an appropriate synthetic resin such as a fluororesin may be used as the dielectric substrate. Further, the earth plate 18 is not limited to a square, but may be a circle. In the above embodiment, the outer conductor 16b of the satellite wave transmitting coaxial cable 16 is used as a short pin. However, the present invention is not limited to this. A short pin similar to the short pins 20, 20, 20 provided at the center of the other side is disposed at the center of the side of the side, and the coaxial cable 16 for satellite wave transmission is suspended at the offset power supply position, Instead of electrically connecting the conductor 16b to the ground plate 18, the conductor 16b may be provided so as to penetrate the ground plate 18.

[0015]

As described above, since the antenna device of the present invention is constituted, the following special effects can be obtained.

The antenna device according to the first aspect can receive both satellite waves and terrestrial waves with a high gain by one unit. And, compared with a conventional pole antenna for receiving a linearly polarized signal of a terrestrial wave, the arrangement height can be made extremely low. Therefore, it is suitable as an antenna device that is installed on the roof of a vehicle and receives S-BAND broadcasts and the like, and does not impair the appearance of the vehicle. If the short pins are soldered to the terrestrial antenna portion made of a plate and the ground plate, the operation can be performed simply and reliably.

According to a second aspect of the present invention, the satellite wave antenna section for receiving the satellite wave is supplied with offset power, the terrestrial wave antenna section for receiving terrestrial waves is supplied with central power, and the power supply position is shifted. No interference.

According to a third aspect of the present invention, the terrestrial vertical element section electrically connected to the center position of the terrestrial antenna section acts as a small monopole antenna to improve the directional characteristics of the terrestrial wave in the horizontal direction. Have been.

In the antenna device according to the fourth aspect, the terrestrial antenna portion is supported and disposed at a predetermined distance from the ground plate by the insulating support member surrounding the short pin, so that the support structure is relatively simple. is there.

According to the antenna device of the present invention, since the outer conductor of the satellite wave transmitting coaxial cable acts as a short pin, the satellite wave transmitting coaxial cable has no bad influence on the terrestrial antenna portion. There is no.

According to a sixth aspect of the present invention, there is provided an antenna device having a low height, wherein a dimension between a satellite wave antenna portion and a terrestrial wave antenna portion can be reduced by using a ceramic substrate having a high dielectric constant. can do.

In the antenna device according to the present invention, a low-noise amplifier is provided on the back surface of the earth plate, and the low-noise amplifier is covered with a shield cover.
Moreover, noise is not superimposed during transmission of a signal from the antenna to the amplifier.

Since the antenna device according to the present invention is housed in a flat case having a low height, the appearance of the vehicle is not impaired even if it is arranged on a roof of the vehicle.

[Brief description of the drawings]

FIG. 1 is a plan view of an embodiment of an antenna device according to the present invention.

FIG. 2 is a front view of FIG.

FIG. 3 is a sectional view taken along the line AA of FIG. 1;

FIG. 4 is a longitudinal sectional view of the antenna device of FIG. 1 in a state in which the antenna device is housed in the case;

FIG. 5 is a diagram illustrating gain characteristics of an E plane with respect to a satellite wave.

FIG. 6 is a diagram illustrating gain characteristics of an E-plane with respect to a terrestrial wave.

FIG. 7 is a diagram illustrating gain characteristics of an H plane with respect to a terrestrial wave.

[Explanation of symbols]

10. Ceramic substrate 12 Satellite wave antenna 14 Terrestrial antenna 16 Coaxial cable for satellite wave transmission 16a center conductor 16b outer conductor 18 Ground plate 20 short pins 22 Insulating support members 24 Vertical element for ground wave 28 Shield cover 30 cases

Continuation of front page    F term (reference) 5J021 AA02 AA06 AB02 AB06 HA05                       HA07 HA10 JA03 JA05 JA06                 5J045 AA03 AA06 AA12 DA10 HA06                       MA04 NA01 NA02

Claims (8)

[Claims] 1. A satellite wave antenna unit is provided on a surface of a dielectric substrate, and a terrestrial wave antenna unit made of a plate material larger than an outer shape of the dielectric substrate is provided in contact with a back surface of the dielectric substrate. A ground plate made of a plate material larger than the outer shape of the terrestrial antenna unit is disposed in parallel on the back side of the body substrate at a predetermined distance from the terrestrial antenna unit, and between the side of the terrestrial antenna unit and the ground plate. A short pin is interposed, and an outer conductor of the satellite wave transmitting coaxial cable is electrically connected to the terrestrial antenna portion, and a center conductor is electrically connected to the satellite wave antenna portion through the dielectric substrate. The ground wave vertical element portion penetrates the earth plate in an insulated state and is electrically connected to the terrestrial antenna portion, and receives a circularly polarized signal from a satellite at the satellite wave antenna portion, An antenna device, wherein the terrestrial antenna unit is configured to receive a terrestrial linearly polarized signal. 2. The antenna device according to claim 1, wherein
The satellite wave antenna section is a rectangular patch antenna, the center conductor of the satellite wave transmission coaxial cable is electrically connected to the offset feeding position of the rectangular patch antenna, and the terrestrial antenna section is rectangular, Wherein the terrestrial vertical element section is electrically connected to the antenna. 3. The antenna device according to claim 2, wherein
An antenna device, wherein the short pin is electrically connected to a center of each of four sides of a square of the terrestrial antenna unit. 4. The antenna device according to claim 1, wherein
An antenna device, wherein the terrestrial antenna unit is supported and arranged at a predetermined interval on the ground plate by an insulating support member surrounding the short pin. 5. The antenna device according to claim 1, wherein
Routing the satellite wave transmitting coaxial cable to the side of the terrestrial antenna portion to electrically connect the outer conductor to the terrestrial antenna portion and electrically connecting the outer conductor to the ground plate; Characterized in that they function as the short pins. 6. The antenna device according to claim 1, wherein
An antenna device, wherein the dielectric substrate is formed of a ceramic substrate. 7. The antenna device according to claim 1, wherein
An antenna device, wherein a low noise amplifier for amplifying the received satellite wave signal and the terrestrial wave signal is provided on the back surface of the ground plate, and the low noise amplifier is covered with a shield cover. 8. The antenna device according to claim 1, wherein the dielectric substrate and the entire ground plate are housed in a case where the front of the satellite wave antenna is a radome and is flat. An antenna device comprising: