JP2000114825A - Antenna power feeder part structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce leak of signals at a power feeder part to an antenna formed by utilizing a radial waveguide. SOLUTION: Concerning a planar antenna 11, the antenna is formed on an antenna side conductive plate 13 of a radial waveguide 12. Near the center of a power feeder side conductive plate 14, an inserting hole 16 is formed and a power feeder probe 15 is inserted. The outside of the power feeder probe 15 is surrounded with a shield member 18. The shield member 18 has a flange part 18a and a coaxial part 18b. The flange part 18a contacts the power feeder side conductive plate 14 at a touch part 19 where a length La in a diameter direction becomes the odd multiple of 1/4 use wavelength. Thus, the leak of signals at the touch part 19 can be reduced. By making the total Lb of the thickness of the power feeding side conductive plate 14 and the length of the coaxial part 18b into odd multiple of 1/4 use wavelength, the leak in the axial direction can be reduced as well.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna feed unit structure provided in a planar antenna or the like used in a microwave band.

[0002]

2. Description of the Related Art In a microwave band for receiving satellite broadcasting and transmitting and receiving satellite communication, a planar antenna formed using a radial waveguide is used. Prior art related to such a planar antenna is disclosed in, for example,
244633 and JP-A-7-235828. In these prior arts, a microwave antenna is formed on one end face of a cylindrical or disc-shaped radial waveguide having a short axial length, and a feeder is provided at the center of the other end face. A conductor probe is inserted into the power supply unit from outside the radial waveguide to form a power supply point. In the prior art of Japanese Patent Application Laid-Open No. 7-235828, the specific structure of the feeding point is unknown. JP-A-6-244633 discloses a structure in which the other end of a power supply probe is connected to a converter, and the converter and the power supply probe are entirely covered with a shield plate and fixed to a frame forming a power supply side end face of the radial waveguide. ing.

In these prior arts, the feed probe is fixed with respect to the radial waveguide. Therefore, the external shield can be sufficiently provided also at the portion where the power supply probe is inserted into the radial waveguide. However, the purpose of forming a planar antenna on the surface of the radial waveguide is to mount it on a mobile object such as an automobile and receive radio waves from the satellite while automatically tracking the direction of the geostationary satellite. That is. For this purpose,
It is desirable that the radial waveguide be angularly displaceable.

FIG. 5 shows a schematic configuration of a planar antenna 1 used for receiving radio waves from a satellite. A microwave antenna is formed on the surface of the antenna-side conductive plate 3 on one end surface side of the disk-shaped or flat cylindrical radial waveguide 2. An insertion hole 6 into which the power supply probe 5 is inserted from the outside is formed at a substantially central portion of the power supply side conductive plate 4 facing the antenna side conductive plate 3. Power supply probe 5
Is covered with an insulating coating 7, inserted into the insertion hole 6, the exposed portion of the tip projects into the radial waveguide 2, and is inserted into the radial waveguide 2 from an antenna provided on the antenna-side conductive plate 3. Receives incoming signal. Planar antenna 1
Can be angularly displaced about the power supply probe 5.
Thus, even if the planar antenna 1 has a sharp directivity, it can be automatically tracked toward the position of the satellite with the angular displacement centered on the feeding probe 5.

[0005] If the radio wave leaks at the insertion hole 6, the receiving sensitivity is reduced, so that the periphery of the power supply probe 5 is surrounded by the shield member 8. The shield member 8 is formed of a conductor such as a metal, and is electrically in contact with the power supply side conductive plate 4 at a contact portion 9. The inner peripheral side of the shield member 8 is spaced from the outer peripheral side of the insulating coating 7, the feeding probe 5 including the insulating coating 7 is fixed, and the planar antenna 1 is configured to be able to angularly displace around it. I have. Prior art for such a power supply portion is disclosed in Japanese Patent Laid-Open No. 5-1 / 5-1.
21912 and the like.

[0006]

In the structure of the power supply portion as shown in FIG. 5, the shield member 8 and the power supply side conductive plate 4 come into contact with each other at the contact portion 9 to provide an electric connection around the insertion hole 6. Prevents leaks. However, the radial waveguide 2
The antenna-side conductive plate 3 and the feed-side conductive plate 4 are combined to form a three-dimensional cylindrical shape, and the insertion hole 6 is formed near the center of the feed-side conductive plate 4. Tends to have small protrusions and irregularities. Further, even on the surface of the shield member 8 facing the contact portion 9, fine projections and the like may exist unless polishing or the like is performed with extremely high precision. If fine protrusions or irregularities are present in the contact portion 9, surface contact becomes incomplete, leakage occurs, and loss at the power supply portion increases.

In a structure in which the feeding section is fixed, the loss can be reduced by sufficiently shielding, but when the directivity direction is changed, it cannot be changed only by the antenna portion. It is necessary to change the direction of the directivity by performing displacement on the whole including the portion connected via the feeding probe. For this reason, the displacement mechanism becomes large. In addition, since the signal received by the antenna must be finally input to a stationary receiving device, it is necessary to provide a slip ring, a rotary joint, or the like in the middle of the signal transmission system. The frequency band received by the planar antenna is a microwave band and has a very high frequency, so that a slip ring gear rotary joint or the like must be used for high frequency and expensive.

It is an object of the present invention to provide an antenna power supply unit structure that can reliably prevent leakage at a portion where a power supply probe is inserted.

[0009]

According to the present invention, there is provided an antenna feed section structure formed on the other end face of a radial waveguide having an antenna formed on one end face, wherein a feed side end face of the radial waveguide is provided. In the conductive plate to be formed, an insertion hole is formed at the power supply position, inserted so as to protrude into the radial waveguide from the insertion hole, and a power supply probe having an outer diameter smaller than the inner diameter of the insertion hole, and a power supply probe. It has an inner diameter larger than the outer diameter, and surrounds the power supply probe outside the radial waveguide while keeping an interval with the outer peripheral surface of the power supply probe, and a portion in contact with the conductive plate in which the insertion hole is formed has a power supply portion. An antenna feed comprising a shield member formed of a conductive material so as to form a flange extending at an odd multiple of one-fourth of a wavelength to be used outside in a radial direction of the probe. Part structure

According to the present invention, an antenna is formed on one end face of a radial waveguide. The conductive plate forming the other end surface of the radial waveguide has an insertion hole formed at a power supply position, and is provided with a power supply portion structure including a power supply probe and a shield member. The feeding probe has an outer diameter smaller than the inner diameter of the insertion hole, and is inserted so as to protrude from the insertion hole into the radial waveguide. The shield member has an inner diameter larger than the outer diameter of the power supply probe, and surrounds the power supply probe outside the radial waveguide while keeping an interval with the outer peripheral surface of the power supply probe. A portion of the shield member that comes into contact with the conductive plate in which the insertion hole is formed is a flange extending outward in the radial direction of the power supply probe with a length that is an odd multiple of a quarter of the wavelength to be used. It is formed. Since the length of the contact portion between the shield member and the power supply side conductive plate is an odd multiple of one-fourth of the wavelength used radially outward of the power supply probe, a signal is generated inside the contact portion. Even if the amplitude of
The amplitude becomes small outside the contact portion separated by an odd multiple of one-half wavelength, and it is possible to prevent the signal from leaking to the outside.

In the present invention, the shield member is fixed to the radial waveguide at a contact portion serving as the flange, and is relatively angularly displaceable about the power supply probe.

According to the present invention, the shield member is fixed to the conductive plate on the power supply side of the radial waveguide at the flange portion and can be relatively angularly displaced around the power supply probe. Thus, the directional direction of the antenna formed on the antenna-side end surface can be easily changed by angular displacement around the antenna.

The present invention is characterized in that the sum of the thickness of the conductive plate and the length of the shield member in the axial direction of the power supply probe is an odd multiple of 1/4 of the wavelength.

According to the present invention, the sum of the length of the shield member surrounding the power supply probe and the thickness of the conductive plate is an odd multiple of 1/4 of the wavelength. Can be minimized in the axial direction.

[0015]

FIG. 1 shows a schematic configuration of a planar antenna 11 according to an embodiment of the present invention. The planar antenna 11 is formed on the surface of the antenna-side conductive plate 13 on one end surface side of the radial waveguide 12. A power-supply-side conductive plate 14 is provided to face the antenna-side conductive plate 13. The power supply side conductive plate 14 has an insertion hole 16 in which the power supply probe 15 is inserted substantially at the center. The power supply probe 15 is electrically insulated around its periphery by an insulating coating 17 or the like. The distal end portion of the power supply probe 15 is not provided with the insulating coating 17, and is received in the radial waveguide 12 from the antenna formed on the surface of the antenna-side conductive plate 13 into the radial waveguide 12. Receive the signal.

Radial waveguide 1 by feeding probe 15
A shield member 18 surrounds the power supply probe 15 to provide shielding around the power supply portion to the power supply 2. The shield member 18 has a flange portion 18a and a coaxial portion 18b. The flange portion 18a is formed so as to extend outward in the radial direction of the power supply probe 15, and the radial length La of the contact portion 19 that comes into contact with the power supply side conductive plate 14 is an odd multiple of 1/4 of the wavelength. is there. If the radial length La of the contact portion 19 is an odd multiple of one-fourth of the wavelength, the contact portion 19 will not contact even if the amplitude of the electric field component or the magnetic field component of the signal reaches its peak. Outside the part 19, the strength of the electric or magnetic field
Become closer to Thereby, even if there is some gap in the contact portion 19, it is possible to prevent signal leakage. If leakage around the insertion hole 16 of the power supply probe 15 can be prevented, a signal received by the antenna can be effectively transmitted to the power supply probe 15 and signal loss can be avoided. The coaxial portion 18 b extends in the axial direction of the power supply probe 15, and the inner peripheral surface is arranged at a distance from the outer peripheral surface of the insulating coating 17 covering the periphery of the power supply probe 15.

In the present embodiment, also in the axial direction of the power supply probe 15, the total value Lb of the lengths of the coaxial portions 18a of the antenna-side conductive plate 13 and the shield member 18 is 4 wavelengths.
Since it is formed so as to be an odd multiple of one-half, signal leakage can be prevented.

FIG. 2 shows an example of the configuration of a planar antenna formed on the antenna-side conductive plate 13 of FIG. A plurality of microstrip antenna elements 20 are arranged on the surface of the antenna-side conductive plate 13 of the radial waveguide 12. The microstrip antenna elements 20 respectively correspond to the same polarized waveform type, and the direction of the directivity as a whole is determined based on the geometric relationship of the arrangement. The antenna beam 21 indicating directivity is sharply formed in one specific direction, so that a relatively small planar antenna 11 can obtain a gain necessary for receiving radio waves from a satellite, for example.

FIG. 3 shows a schematic configuration of an antenna device which can receive a radio wave from a satellite while tracking it using the planar antenna 11 of FIG. Antenna beam 21
Is directed in a direction inclined by a tilt angle θ (0 <θ <90 °) from a normal to the surface of the antenna-side conductive plate 13 of the radial waveguide 12. The planar antenna 11 has an inclined antenna beam 21 for receiving radio waves from a broadcasting satellite (BS) or a communication satellite (CS) on a geostationary satellite orbit provided on the equator of the earth.

The planar antenna 11 is mounted on a base 22. A bearing 23 is provided between the base 22 and the radial waveguide 12 of the planar antenna 11. An external gear 24 is formed on the outer peripheral surface of the radial waveguide 12, and meshes with a drive gear 26 of a motor 25 mounted on the base 22 so that the motor 25 can be driven to rotate. Motor 2
When the 5 is rotated, the planar antenna 11 can change the antenna beam 21 with respect to the surface of the base 22.

The base 22 is provided with a converter 27 for reducing the frequency of the signal received by the planar antenna 11. When the planar antenna 11 receives a signal in a frequency band of, for example, 12 GHz, the converter 27 converts the signal into a signal in a frequency band of 1 GHz, for example. This is because lowering the frequency facilitates subsequent handling. Converter 27 is provided inside shield case 28, and shield case 28 contacts shield member 18. However, since the shield case 28 is fixed to the base 22, the space between the shield case 28 and the shield member 18 cannot be fixed. Since the length of the shield member 18 in the axial direction of the power supply probe 15 and the thickness of the power supply side conductive plate 14 are formed at an odd multiple of 1/4 of the wavelength, the coaxial portion 18b of the shield member 18 is formed.
Of the signal from between the tip of the shield case 28 and the shield case 28 can be reduced. In the shield case 28,
The circuit board 29 is housed, and the converter circuit 30 is mounted.

As shown in FIG. 4, the antenna-side conductive plate 13
Microstrip antenna element 2 formed on the surface of
Numeral 0 is arranged on the surface of the antenna-side conductive plate 13 via the dielectric plate 31. Signal transmission between the inside of the radial waveguide 12 and the microstrip antenna element 20 is performed by a feed probe 32. The distal end of the feed probe 32 is connected to the microstrip antenna element 20, and the proximal end protrudes into the radial waveguide 12. In the radial waveguide 12, a signal is transmitted between the base end side of the power supply probe 32 and the protruding portion at the distal end of the power supply probe 15.

In the present embodiment, signal leakage around the insertion hole 16 of the power supply probe 15 is reduced.
About 2d compared to the prior art power supply structure shown in FIG.
The effect of reducing the loss by about B is obtained.

[0024]

As described above, according to the present invention, the shield member for covering the periphery of the power supply probe inserted on the power supply side of the radial waveguide forming the antenna is used with the power supply side conductive plate of the radial waveguide. Since the contact is made at a length that is an odd multiple of one-fourth of the wavelength, the signal leakage from the contact portion can be reduced and the loss of the signal at the power supply portion can be prevented.

Further, according to the present invention, the antenna including the shield member can be angularly displaced around the power supply probe, and furthermore, the loss of the signal from the power supply part can be prevented and the loss can be suppressed.

Further, according to the present invention, the shield member has an odd multiple of one-fourth of the signal frequency in the axial direction of the feed probe together with the thickness of the conductive plate on the feed side of the radial waveguide. Therefore, signal leakage in the axial direction of the feeding probe can be reduced, and a decrease in gain as an antenna can be suppressed.

[Brief description of the drawings]

FIG. 1 is a plan sectional view showing a schematic configuration of a planar antenna 11 according to an embodiment of the present invention.

FIG. 2 is a simplified plan view of the planar antenna 11 of FIG.

FIG. 3 is a schematic side sectional view of an antenna device constituting the planar antenna 11 of FIG. 1;

FIG. 4 is a schematic side sectional view of the microstrip antenna element of FIG. 2;

FIG. 5 is a simplified side sectional view showing a conventional antenna feed unit structure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Planar antenna 12 Radial waveguide 13 Antenna side conductive plate 14 Feeding side conductive plate 15 Feeding probe 16 Insertion hole 18 Shield member 18a Flange part 18b Coaxial part 19 Contact part 20 Microstrip antenna element 21 Antenna beam 27 Converter 28 Shield case

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshiaki Minami 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Corporation F-term (reference) 5J021 AA05 AA09 AA11 AB06 CA02 GA02 GA05 GA08 HA05 HA07 5J045 AA27 AB06 DA10 FA02 HA01 HA06 JA03 LA01 MA04 NA01

Claims (3)

[Claims] In an antenna feed portion structure formed on the other end face of a radial waveguide having an antenna formed on one end face, a conductive plate forming a feed side end face of the radial waveguide is supplied with power. A power supply probe having an outer diameter smaller than the inner diameter of the insertion hole, and having an inner diameter larger than the outer diameter of the power supply probe, the power supply probe being inserted so as to protrude from the insertion hole into the radial waveguide; Then, while maintaining a distance from the outer peripheral surface of the power supply probe, the power supply probe is surrounded outside the radial waveguide, and a portion in contact with the conductive plate in which the insertion hole is formed is radially outward of the power supply probe. And a shield member formed of a conductive material so as to form a flange extending at an odd multiple of a quarter of the wavelength to be used. 2. The shield member is fixed to the radial waveguide at a contact portion serving as the flange, and is relatively angularly displaceable about the power supply probe. Antenna feed structure. 3. The apparatus according to claim 1, wherein the sum of the thickness of the conductive plate and the length of the shield member in the axial direction of the power supply probe is an odd multiple of 波長 of the wavelength. Or the antenna feeder structure according to 2.