JP2002223117A - Antenna feeding system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antenna feeding system that can change a direction of a radio wave on the way of a feeding system at a low loss without deteriorating the cross polarization characteristic. SOLUTION: In the antenna feeding system configured of an antenna 1, an oversized flexible waveguide 2, an undesired mode filtering waveguide 3, two conical horns 10, 20, 4 focus reflecting mirrors 11-14, an oversized circular waveguide 4, a cross polarized wave compensation waveguide 5, and a combining branching filter 6, every time the radio wave emitted from the conical horns is made incident onto each reflecting mirror, the 4 reflecting mirrors are paced in a way that the radio wave is apart from a horizontal in-plane rotary shaft of the antenna, concave mirrors are adopted for the three reflecting mirrors 12-14 and the undulatory cross polarization cancellation conditions are satisfied.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oversized flexible waveguide used between a multi-frequency antenna and a wireless device in the field of wireless communication, an unnecessary form filter waveguide,
The present invention relates to an antenna feed system including two primary radiators, four focusing reflectors, an oversized circular waveguide, a cross polarization compensation waveguide, and a multiplexer / demultiplexer.

[0002]

2. Description of the Related Art An antenna and an oversized flexible waveguide,
The antenna feed system including the unnecessary form filter waveguide, the oversized circular waveguide, the cross polarization compensating waveguide, and the multiplexer / demultiplexer has a feature that the feed length can be increased because of low loss. However, in this oversized circular waveguide,
If there is a discontinuous point such as a bend or a step in the middle, reflection occurs and a higher-order mode wave is generated there, and the cross polarization discrimination characteristic and the VSWR (voltage standing wave rati) are generated.
o: Electrical characteristics such as voltage standing wave ratio) characteristics are significantly impaired. For this reason, the oversized circular waveguide is piped vertically below with high precision, and there is a disadvantage that the direction of the radio wave cannot be changed on the way.

As shown in FIG. 3, in order to eliminate the above-mentioned drawbacks, a conventional antenna feed system includes an antenna 1, an oversized circular flexible waveguide 2, an unnecessary-shaped filtered waveguide 3, an oversized circular waveguide. There is a waveguide comprising a waveguide 4, a cross polarization compensating waveguide 5, a multiplexer / demultiplexer 6, and a plurality of rectangular waveguides 7. Although the unnecessary form filter waveguide 3 is a filter that absorbs higher-order mode waves propagating from the antenna 1, it can only absorb a specific mode. The cross polarization compensating waveguide 5 has a function of reducing cross polarization components generated from the oversized circular flexible waveguide 2 and the oversized circular waveguide 4.

In the above-described antenna feed system, the frequency is demultiplexed by the multiplexer / demultiplexer 6 at a portion where the pipe needs to be bent,
It is possible to bend in an arbitrary direction by the rectangular waveguide 7 which does not deteriorate the cross polarization discrimination degree in which only the fundamental mode propagates. After bending, the rectangular waveguide 7 is combined with the multiplexer / demultiplexer 6 and the oversize circular. By connecting the waveguide 4, electric waves can be supplied in any direction. However, there is a disadvantage that the cross polarization characteristic and the VSWR characteristic are deteriorated by the added multiplexer / demultiplexer 6.

[0005]

In the conventional antenna feed system as described above, not only the configuration of the feed system becomes complicated, but also the loss, the VSWR, and the cross polarization discrimination characteristics of the multiplexer / demultiplexer 6 deteriorate. There was a problem to do.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and is intended to change the direction of radio waves so as to have low loss and no deterioration of cross polarization characteristics in the middle of a power supply system. It is an object of the present invention to obtain an antenna feed system that can perform the above-described operations.

[0007]

According to the present invention, there is provided an antenna feed system comprising: an oversize flexible waveguide, an unnecessary form filter waveguide for filtering an unnecessary form, and an oversize circular form. In the waveguide, the cross-polarization compensating waveguide for reducing the cross-polarization component, and the antenna feed system for feeding power through the multiplexer / demultiplexer, the unnecessary form filter waveguide and the oversize flexible waveguide are used. A convergent horn, a fourth converging reflector comprising a plane reflecting mirror, a third converging reflecting mirror comprising a rotating quadric mirror, from the side closer to the antenna,
A second focusing reflector, a first focusing reflector, and another conical horn are sequentially connected, and a radio wave incident on the conical horn connected to the unnecessary form filter waveguide is transmitted to a horizontal axis of rotation of an antenna. The light is repeatedly incident on and reflected from each of the reflecting mirrors so as to move away from the conical horn connected to the oversized circular waveguide, and the first to third focusing mirrors are concave mirrors. It is characterized by having.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 is a configuration diagram showing an antenna feed system according to Embodiment 1 of the present invention, in which an antenna, an oversized flexible waveguide, an unnecessary shape filtered waveguide, two conical horns, and four , An oversized circular waveguide, a cross polarization compensating waveguide, and a multiplexer / demultiplexer constitute an antenna feed system.

In FIG. 1, the same portions as those of the conventional example shown in FIG. 3 are denoted by the same reference numerals, and description thereof will be omitted. As a new code, 10 is a first conical horn, 11 is a fourth focusing reflector made of a plane reflecting mirror, 12 is a third focusing reflecting mirror made of a concave mirror, 13 is a second focusing reflecting mirror made of a concave mirror,
Reference numeral 14 denotes a first focusing reflector formed of a concave mirror. And
Each of the focusing reflectors 11, 12, 13, and 14 is arranged such that the radio wave 30 supplied to the second conical horn 20 sequentially goes away from the horizontal axis of rotation 40 of the antenna every time passing through the focusing reflector. ing.

Here, each of the focusing mirrors 11, 12, 13,
A description will be given of the conditions for canceling the wave cross-polarization of the radio wave incident on. Consider the mirror system such as FIG. 2 configured in N pieces of rotational quadric surface mirror, the order the focal distance from the reflector close to the conical horn f _1, f _2, · · ·, When f _n, the focal The distance has the relationship shown in equation (1). In FIG. 2, reference numeral 10 denotes a first conical horn similar to that shown in FIG. 1, 15 denotes a reflecting mirror # 1, 16 denotes a reflecting mirror # 2, 17 denotes a reflecting mirror # 3, and 18 denotes a reflecting mirror # N-1 and 19 are reflecting mirrors #N.

[0011]

(Equation 1)

Here, n = 1, 2,..., N,
N is a natural number of 1 or more. Further, R _n and R _n ′ are the radius of curvature of the wavefront incident on the reflecting mirror #n and the radius of curvature of the reflected wavefront, respectively, and take a value (−) when there is a focus in the traveling direction of the light beam. In equation (1), when f _n is positive, the mirror is a concave mirror, and when f _n is negative, the mirror is a convex mirror.

Further, if the beam radii of the reflector near the conical horn 10 are ω1, ω2,..., ΩN and the angles σ1, σ2,. Proceedings of the 2000 IEICE General Conference,
Communication 1, B-1-156, "Wave dynamic cross-polarization cancellation condition of multiple reflector antenna", as shown on page 156, generated from each reflector of a multiple reflector offset antenna composed of N reflectors. The cross-polarization canceling condition for canceling mutually cross-polarized components that take into account each other in consideration of the phase is given by the following equation (2).
Given by

[0014]

(Equation 2) here,

(Equation 3) It is. Also, k _n is a vector indicating the traveling direction of the radio wave,
j ₁ is a vector perpendicular to the paper surface of FIG.

The wave-dynamic cross-polarization canceling condition of the equation (2) is a geometric relational expression that is not related to the frequency. In a mirror system satisfying this relation, no cross-polarization occurs regardless of the frequency. From this result, two conical horns and each focusing reflector 1
1, 12, 13, and 14 can be applied to the antenna feed system without deteriorating the cross polarization characteristics.

Each of the focusing mirrors 11, 12, 1 shown in FIG.
Four-reflector mirror-type focused beam feeding system composed of 3 and 14
The wave-dynamic cross-polarization elimination condition is expressed as follows:
f_Four= 0 is given by the following equation (4). here,
The mirror system of FIG. _n= Sign (j₁・ (K
_n× k_{n + 1})), Q₁= -1, q_Two= + 1, q_Three= -1
Becomes

[0017]

(Equation 4)

As described above, the four-reflecting mirror-type focused beam feeding system applied to the antenna feeding system according to the present embodiment has the focused reflection so as to satisfy the wave dynamic cross polarization canceling condition of the equation (2). Considering the phase of the cross-polarization components generated by the mirrors, the focusing mirrors cancel each other out so that there is no frequency characteristic, so that the cross-polarization can be completely zero regardless of the frequency. Since the frequency can be effectively used, the transmission capacity can be increased.

In further summary, according to the present invention, an antenna and an oversized flexible waveguide, an unnecessary shape filtered waveguide, an oversized circular waveguide, a cross polarization compensating waveguide, and a multiplexing / demultiplexing device. In the antenna feed system consisting of a reflector, a conical horn, a fourth focusing mirror consisting of a plane reflecting mirror, and a rotating secondary are sequentially arranged from the side close to the antenna between the unnecessary form filtering waveguide and the oversized circular waveguide. A radio wave incident on the conical horn which is connected to the third focusing reflector, the second focusing reflector, the first focusing reflector, and the other conical horn, which is formed of a curved mirror, and which is connected to the unnecessary form filter waveguide. However, it repeatedly enters and reflects on each reflector so as to be away from the horizontal axis of rotation of the antenna, and enters the other conical horn connected to the unnecessary form filter waveguide. It is possible to change the direction of the radio wave propagating the cross-polarization component generated in each focused reflectors phase also can cancel each other into account.

In addition, since concave mirrors are used as the first to third focusing reflectors, spillover components from the reflectors can be reduced as compared with the convex mirrors, and effective use of frequency can be achieved, thereby increasing transmission capacity. There is an effect that an antenna feed system that can achieve the above is obtained.

In the above, the case where a conical horn is used as the primary radiator has been described. However, the present invention is not limited to this, and any horn having a central axis may be attached as the primary radiator.

[0022]

As described above, according to the present invention, a conical horn and a plane reflecting mirror comprising a conical horn and a plane reflecting mirror are arranged between the unnecessary-form filtered waveguide and the oversized circular waveguide sequentially from the side near the antenna. By connecting a focusing mirror, a third focusing mirror consisting of a rotating quadric mirror, a second focusing mirror, a first focusing mirror, and another conical horn, low loss and crossing occur in the feeding system. There is an effect that the direction of the radio wave can be changed so that the polarization characteristics do not deteriorate.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an antenna feed system according to an embodiment of the present invention.

FIG. 2 is a diagram showing a mirror system of an N-reflector offset antenna for explaining the operation of the present invention;

FIG. 3 is a configuration diagram showing a conventional antenna feed system.

[Explanation of symbols]

1 antenna, 2 oversized circular flexible waveguide, 3
Unnecessary form filter waveguide, 4 oversized circular waveguide,
5 cross polarization compensating waveguide, 6 multiplexer / demultiplexer, 7 square waveguide, 8 reflecting mirror # 2, 10 first conical horn, 11
Fourth focusing reflector, 12 Third focusing reflector, 13 Second focusing reflector, 14 First focusing reflector, 15 Reflector # 1, 1
6 Reflector # 2, 17 Reflector # 3, 18 Reflector #N
-1,19 reflector # N, 20 second conical horn, 3
0 Radio wave, 40 antenna Rotation axis in horizontal plane.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Takamasa Furuno 2-12-5 Iwamotocho, Chiyoda-ku, Tokyo F-term (reference) 5J020 AA03 BA06 BA09 BC06

Claims (1)

[Claims] 1. An oversize flexible waveguide, an unnecessary form filter waveguide for filtering an unnecessary form, an oversize circular waveguide, and a cross polarization for reducing a cross polarization component. In an antenna feed system for feeding power via a wave compensating waveguide and a multiplexer / demultiplexer, a conical horn is provided between the unnecessary form filtering waveguide and the oversized flexible waveguide from a side close to the antenna. ,
Connecting a fourth focusing mirror consisting of a plane reflecting mirror, a third focusing mirror consisting of a rotating quadric mirror, a second focusing mirror, a first focusing mirror, and another conical horn sequentially; An antenna feed system wherein the first to third focusing reflectors are concave mirrors.