JP2002171124A - Antenna device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antenna device which can receive both of a circularly polarized wave signal from a satellite and a linear polarized wave signal of surface waves transmitted by a repeater which received the circularly polarized wave signal by a set of antenna device with short antenna. SOLUTION: A first plane electrode 12 is formed on a front surface of a ceramic substrate 10, and a second plane electrode 14 is formed on a rear surface thereof. Each plates 16 are arranged at a predetermined internal in parallel to each other on a side of the second plane electrode 14, and first coaxial line 26 is penetrated through the earth plate 16 from a side of the earth plate 16, so that an external conductor 26a is electrically connected to it and the second plane electrode 14. A central conductor 26b is penetrated through the ceramic substrate 10 to offset-feed the first plane electrode 12. An external conductor 28a of a second coaxial line 28 is electrically connected to the earth plate 16, a central conductor 28b is fed to a center of the second plane electrode 14, and a short pin 18 in interposed between the second plane electrode 14 and the earth plate 16. The first plane electrode 12 receives a circularly polarized wave signal, and the second plane electrode 14 receives a linear polarized wave signal.

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. This is because, for example, in Sirius radio, a circularly polarized signal of 2320 to 2332.5 MHz is transmitted from a broadcasting satellite, and this circularly polarized signal is received by a repeater on the ground, and 2324.2 to 2328 is transmitted as a terrestrial wave. This is a broadcasting system in which a .3 MHz linearly polarized signal is retransmitted. Areas along highways where circularly polarized signals from satellites are obstructed by large buildings are covered by linearly polarized terrestrial signals from repeaters.

[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 has a first surface on a dielectric substrate.
Forming a second planar electrode on the back surface of the dielectric substrate, disposing a ground plate parallel to the second planar electrode side of the dielectric substrate at a predetermined interval, A first coaxial line is passed through the ground plate from the ground plate side, and an outer conductor thereof is electrically connected to the ground plate and electrically connected to the second plane electrode; A central conductor is passed through the dielectric substrate and electrically connected to the first planar electrode;
An outer conductor of a second coaxial line is electrically connected to the ground plate, a center conductor of the second coaxial line is electrically connected to the second plane electrode, and the second plane electrode and the ground plate are electrically connected. A short pin is interposed therebetween, and the first plane electrode is configured to receive a circularly polarized signal from a satellite, and the second plane electrode is configured to receive a terrestrial linearly polarized signal. I have.

The first plane electrode is a rectangular patch antenna, the center conductor of the first coaxial line is electrically connected to a position where offset power is supplied to the rectangular patch antenna, and the second plane electrode is also connected to the first plane electrode. A central conductor of the second coaxial line may be electrically connected to a central position of the rectangular patch antenna.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is an external view of an embodiment of the antenna device of the present invention, in which (a) is a plan view and (b) is a front view. FIG. 2 shows A of FIG.
It is a figure which shows an electrical structure in the -A cross section. FIG. 3 is a partial longitudinal sectional view of a state where the antenna device of FIG. 1 is housed in a case. FIG. 4 is an antenna directivity diagram for a circularly polarized signal. FIG. 5 is a Smith chart for a circularly polarized signal. FIG. 6 is a VSWR characteristic diagram for a circularly polarized signal. FIG. 7 is an antenna directivity diagram for a linearly polarized signal. FIG. 8 is a Smith chart for a right circular polarization signal. FIG. 9 is a VSWR characteristic diagram for a linearly polarized signal. 4 to 9 are characteristic diagrams in the frequency band of Sirius radio. Similar characteristics can be obtained in the XM radio.

In FIG. 1, a first planar electrode 12 as a rectangular patch antenna is formed on the surface of a ceramic substrate 10 as a dielectric substrate having a square planar shape, and a second planar electrode 14 is formed on the entire back surface. Is done. This second plane electrode 14 is a rectangular patch antenna,
It also functions as a ground plate for the first plane electrode. Also,
A ground plate 16 having a large-diameter circular plane made of a conductive metal plate having a larger area than the ceramic substrate 10 is arranged on the second plane electrode 14 side parallel to and separated from the ceramic substrate 10 by a predetermined distance. You. Short pins 18 made of a dielectric metal are interposed between the second plane electrode 14 and the ground plate 16. Both ends of the short pins 18 are electrically connected to the second plane electrode 14 and the ground plate 16 by soldering or the like, respectively.

Further, a printed circuit board 20 is provided on the back surface of the ground plate 16, that is, on the surface opposite to the ceramic substrate 10, and electronic components are mounted thereon to form a low noise amplifier. And the printed circuit board 2
The output cable 22 is derived from 0. Further, a shield cover 24 is provided so as to cover the low noise amplifier provided on the printed circuit board 20. Although not shown, a low-noise amplifier that amplifies a circularly polarized wave signal received by the first plane electrode 12 and a low-noise amplifier that amplifies a linearly polarized wave signal received by the second plane electrode 14 include:
The position is divided and mounted on the printed circuit board 20. Further, the cider cover 24 is configured to separately shield a low-noise amplifier for circularly polarized signals and a low-noise amplifier for linearly polarized signals. As an example, the inside of the shield cover 24 may be divided into two sections, and each section may cover the low-noise amplifier, or two shield covers may cover the two sections of the low-noise amplifier. .

Further, the center conductor of the first coaxial line is electrically connected to the first plane electrode 12 at a position where offset power is supplied, and the center conductor of the second coaxial line is electrically connected to the center of the second plane electrode 14. Connection. The connection between the first and second coaxial lines will be described with reference to FIG.

In FIG. 2, a first coaxial cable 26 is provided to penetrate from the ground plate 16 side, and an outer conductor 26a of the first coaxial cable 26 is connected to the ground plate 16 and the second plane electrode 14. It is electrically connected by soldering or the like. The center conductor 26b of the first coaxial cable 26 penetrates through the ceramic substrate 10 and is electrically connected to the first plane electrode 12 by soldering or the like. The position where the center conductor 26b of the first coaxial cable 26 is electrically connected to the first plane electrode 12 is such that the square first plane electrode 12 acts as a patch antenna capable of receiving a circularly polarized signal. , Is an offset position on a line connecting diagonal lines of a rectangle and deviated from the center.

A second coaxial line 28 is provided from the ground plate 16 side and penetrates the second coaxial line 28.
The outer conductor 28a is electrically connected to the ground plate 16 by soldering or the like, and its center conductor 28b is electrically connected to the second plane electrode 14 by soldering or the like. The position where the center conductor 28b of the second coaxial line 28 is electrically connected to the first plane electrode 12 is at the center of the second plane electrode 14.

Further, two short pins 18, 18
Are interposed between the second flat electrode 14 and the ground plate 16 at substantially opposite ends on the diagonal line of the second flat electrode 14 and are electrically connected by soldering or the like.

The antenna device 30 having such a configuration is housed in a case 32 as shown in FIG. The structure of the case 32 is as follows. First, the metal case base 3
A cylindrical portion protrudes coaxially with the hole formed in the center of 4,
A male screw 34a is engraved on the outer periphery. Then, the case base 36 is covered with a case lid 36 made of a dielectric resin, and is appropriately fixed with screws or the like. In addition, an O-ring 38 is interposed between the case base 34 and the case lid 36, and has a watertight structure with respect to the outside of the case in a state where the inside is disposed. Also, the ground plate 1 is attached to the case lid 36.
6 is appropriately fixed with screws or the like, and the entire antenna device 30 is fixed to the case cover 36. Here, the case lid 3 facing the ground plate 16 and the first plane electrode 12.
Portion 6 functions as a radome having an appropriate dielectric constant.

The case 32 for housing the antenna device 30 is provided with a male screw 34a inserted from the outside into a hole formed in the roof of the vehicle or the like, and a nut 40 is screwed from the inside to be disposed and fixed. A pad member 42 made of rubber or the like is interposed between the case base 34 and the roof of the vehicle.
Rainwater and the like are prevented from entering the vehicle through holes formed in the roof. Then, an output cable 2 appropriately connected to the antenna device 30 and transmitting an antenna reception signal.
2 is drawn into the vehicle through a hole in case base 34 of case 32.

The results of measurements performed by the present inventors on the antenna device 30 of the present invention having such a configuration will be described.
In the antenna device 30 of the present invention, which is a measurement target, the ceramic substrate 10 is a square having a side of 35 mm and a thickness of 4 mm.
mm, and the ground plate 16 is a disk having a diameter of 70 mm. Then, the ceramic substrate 10 and the ground plate 1
The distance between 6 is 7.5 mm. The measurement results show the directional characteristics of vertically upward as shown in FIG. 4 with respect to the circularly polarized signal of 2320 to 2332.5 MHz received by the first plane electrode 12, and as shown in the Smith chart of FIG. 50
An appropriate antenna output impedance close to ohms is obtained, and an extremely good VSWR characteristic is obtained as shown in FIG. Thus, excellent antenna characteristics are obtained for a circularly polarized signal from a satellite.

Further, a signal 23 received by the second plane electrode 14 is received.
For a linearly polarized signal of a ground wave of 24.2 to 2328.3 MHz, an appropriate antenna exhibiting a low elevation angle directivity in the horizontal direction as shown in FIG. 7 and close to 50 ohms as shown in the Smith chart of FIG. An output impedance is obtained, and an extremely good VSWR characteristic is obtained as shown in FIG. Thus, excellent antenna characteristics are obtained even for a linearly polarized signal due to a terrestrial wave from the repeater.

Therefore, the antenna device 30 of the present invention
Has good antenna characteristics with respect to both circularly polarized signals from satellites and linearly polarized signals of terrestrial waves from repeaters, and is suitable as an antenna for S-BAND broadcasting and the like. Moreover, the height at which the case 32 was disposed could be reduced to about 35 mm from the roof of the vehicle. Therefore, the antenna device 30 of the present invention does not impair the appearance of the vehicle.

In the practical example, offset power is supplied to the first plane electrode 12 and central power is supplied to the second plane electrode 14. Therefore, the center conductors 26b and 28b of the first and second coaxial wires 26 and 28 are disposed at separate positions, and there is no mutual interference.
In the present invention, in order to make the antenna device 30 low, the distance between the second plane electrode 14 and the ground plate 16 is set to be small to increase the capacitance component. By providing the antenna component with an appropriate thickness, an inductance component is given, and the antenna output impedance can be adjusted to an appropriate value as shown in FIGS. Further, resonance is likely to occur because the space between the second plane electrode 14 and the ground plate 16 is narrow.
The position of the short pins 18 and the first and second coaxial lines 2
By adjusting the distance to 6, 28, the resonance frequency can be out of the band of the frequency band to be received, so that no problems occur in the antenna characteristics.

In the above embodiment, the first planar electrode 1
2 is a square patch antenna and is fed as offset by feeding offset, thereby acting as a circularly polarized wave antenna. However, the present invention is not limited to this as long as circularly polarized waves can be received. Alternatively, a notch may be provided at both ends of the diameter of the circular patch antenna to supply power at the center. The second plane electrode 14 is not limited to a square, but may be a circle, or may be one in which a feeding point is shifted from the center and offset feeding is performed. Here, the outer shape of the ceramic substrate 10 may be any shape as long as the first and second planar electrodes 12 and 14 can be formed, and is not limited to a square as in the above embodiment. Then, by using the ceramic substrate 10, the dielectric substrate is made thinner and the first and second planar electrodes 12, 1 are formed.
4, the antenna device 30 is thinned so that the overall height is reduced. However, a dielectric substrate having an appropriate dielectric constant may be used. Further, if the dimensions permit, the air layer may act as a dielectric substrate. Further, the ground plate 16 is not limited to a circular plane,
It may have any shape such as a square shape, and preferably has an area as large as possible.

[0021]

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 a circularly polarized signal from a satellite and a linearly polarized signal of a terrestrial wave by one unit. And, compared to a conventional pole antenna or the like for receiving a terrestrial linearly polarized signal, the height of the arrangement can be reduced.
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.

According to the antenna device of the present invention, the first plane electrode for receiving the circularly polarized wave signal is supplied with offset power,
The second plane electrode for receiving the linearly polarized signal is the center feeding, and the feeding position is shifted, so that no mutual interference occurs.

According to the third aspect of the present invention, the antenna device having a low height can be provided by shortening the dimension between the first and second planar electrodes using a ceramic substrate.

In the antenna device according to the fourth aspect, by providing a low noise amplifier on the back surface of the ground plate, a received signal can be immediately amplified, and noise is superimposed during transmission of a signal from the antenna to the amplifier. Nothing.

According to the antenna device of the present invention, a low noise amplifier for amplifying a received circularly polarized signal and a low noise amplifier for amplifying a received linearly polarized signal are separately covered with a shield cover. Therefore, no mutual interference occurs due to the amplified signals.

Since the antenna device according to the sixth aspect is housed in a flat case, the appearance of the vehicle is not impaired even if it is arranged on the roof of the vehicle.

[Brief description of the drawings]

FIG. 1 is an external view of an embodiment of an antenna device according to the present invention, in which (a) is a plan view and (b) is a front view.

FIG. 2 is a diagram showing an electrical structure in an AA cross section of FIG.

FIG. 3 is a partial longitudinal sectional view of a state where the antenna device of FIG. 1 is housed in a case.

FIG. 4 is an antenna directivity diagram for a circularly polarized signal.

FIG. 5 is a Smith chart for a circularly polarized signal.

FIG. 6 is a VSWR characteristic diagram for a circularly polarized signal.

FIG. 7 is an antenna directivity diagram for a linearly polarized signal.

FIG. 8 is a Smith chart for a right circularly polarized signal.

FIG. 9 is a VSWR characteristic diagram for a linearly polarized signal.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Ceramic substrate 12 1st plane electrode 14 2nd plane electrode 16 Ground plate 18 Short pin 24 Shield cover 26 1st coaxial line 26a, 28a Outer conductor 26b, 28b Center conductor 28 2nd coaxial line 30 Antenna device 32 Case

 ────────────────────────────────────────────────── ─── Continued on the front page F term (reference) 5J021 AA02 AA13 AB06 CA01 FA26 HA05 HA07 HA10 JA05 JA06 5J045 AA12 BA01 CA01 CA04 DA10 EA07 JA02 JA03 NA02 NA03 NA04 5J046 AA00 AA07 AB13 RA03 RA05 RA09 UA08

Claims (6)

[Claims] 1. A first planar electrode is formed on a front surface of a dielectric substrate, and a second planar electrode is formed on a back surface of the dielectric substrate. A predetermined distance is provided between the dielectric substrate and the second planar electrode. And a ground plate is disposed in parallel with the second plate electrode, and a first coaxial line is passed through the ground plate from the ground plate side to electrically connect an outer conductor thereof to the ground plate. And electrically connect the center conductor of the first coaxial line to the first plane electrode through the dielectric substrate, and connect the outer conductor of the second coaxial line to the ground plate. Electrically connecting the center conductor of the second coaxial line to the second plane electrode, interposing a short pin between the second plane electrode and the ground plate, The plane electrode receives a circularly polarized signal from the satellite and An antenna device characterized in that the second plane electrode receives a linearly polarized signal of a terrestrial wave. 2. The antenna device according to claim 1, wherein
The first planar electrode is a rectangular patch antenna, and a center conductor of the first coaxial line is electrically connected to a position where offset power is supplied to the rectangular patch antenna, and the second planar electrode is also a rectangular patch antenna. An antenna device characterized in that a central conductor of the second coaxial line is electrically connected to a central position thereof. 3. The antenna device according to claim 1, wherein said dielectric substrate is formed of a ceramic substrate. 4. The antenna device according to claim 1, wherein a low-noise amplifier for amplifying the received circularly polarized signal and the linearly polarized signal is provided on a surface of the ground plate opposite to the dielectric substrate. An antenna device characterized by being provided and configured. 5. The antenna device according to claim 4, wherein
An antenna device, wherein a low-noise amplifier for amplifying the circularly-polarized signal and a low-noise amplifier for amplifying the linearly-polarized signal are separately provided, and each is covered with a cider cover. 6. The antenna device according to claim 1, wherein the whole of the dielectric substrate and the ground plate is housed in a case where a front of the first plane electrode is a radome and is flat. An antenna device characterized by comprising: