JP2616536B2 - Double reflector antenna - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a double reflector antenna suitable for microwave communication and the like.

[0002]

2. Description of the Related Art A conventional double reflector antenna of this type is disclosed in Japanese Patent Laid-Open Publication No. 2-209003 (published on Aug. 1990, 1990).
, A rotating parabolic antenna as a main reflecting mirror, a sub-reflecting mirror for illuminating the rotating parabolic antenna, and a primary radiator for illuminating the sub-reflecting mirror With horn. In this double reflector antenna, a desired antenna radiation pattern is obtained by modifying the mirror surfaces of the primary radiator and the sub reflector in order to adjust the amplitude and phase of the electromagnetic wave applied to the main reflector.

[0003]

In the above-mentioned conventional double reflector antenna, the mirror surface can be corrected more easily than the mirror surface of the main reflector. Need two mirror corrections. Further, the conductor curved surface of the sub-reflection mirror requires precise mirror surface precision, and there is a disadvantage that the cost is increased due to the precision machining of the conductor curved surface.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a double reflector antenna which can obtain a desired antenna radiation pattern by a simple mirror surface correcting means and has a low processing cost.

[0005]

Means for Solving the Problems] double reflector antenna of the present invention, horn and, given radiation pattern of the electromagnetic wave with receiving an electromagnetic wave from the horn that radiates electromagnetic waves
Double that a reflex recto array antenna for re-radiating by the phase correction to be down, Ru and a main reflector of appropriate conductors curved re-emit the electromagnetic waves into space together with receiving an electromagnetic wave from the reflex recto array antenna For reflector antenna
The reflect array antenna re-radiates
When the beam center axis of the electromagnetic wave is directed in the antenna axis direction
In this case, the electromagnetic wave from the horn is
The amplitude decreases as you move away from
Phase as it moves away from the antenna axis
Is re-emitted with a phase correction so that

In one embodiment of the double reflector antenna according to the present invention, the reflect array antenna includes a re-radiating antenna.
The center axis of the beam of the electromagnetic wave in the axial direction of the antenna.
When the turn has a plurality of patch antennas for re-radiation by phase correction so that the phase is delayed with increasing the electromagnetic wave with receiving an electromagnetic wave from the horn in a direction away from the antenna axis, the electromagnetic wave reradiated and a phase shifter of each respective corresponding of the patch antenna to each phase of the electromagnetic waves each respective receives said patch antenna to said phase correction.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings.

FIG. 1 is a conceptual diagram of one embodiment of a double reflector antenna according to the present invention. 2A and 2B are diagrams showing the electromagnetic wave radiation characteristics of the present embodiment. FIG. 2A shows a desired antenna radiation pattern R (= R1), and FIGS. 2B and 2C show radiation patterns on the radiation plane P of the reflect array antenna. Is the electric field distribution (amplitude and phase).

In this double reflector antenna, the feed line 4
Is irradiated on the reflect array antenna 3 by the horn 2 as a primary radiator. Antenna 3
Is a reciprocal or non-reciprocal operation in which N (N is a positive integer) element antennas 31 and one end is connected to each of the element antennas 31 and the electromagnetic wave S1 received from the horn 2 is passed with an appropriate phase shift amount described later. A phase shifter 32 and these phase shifters 3
2 are short-circuited to each other, and the electromagnetic wave S1 from the phase shifter 32 is
Short circuit 33 that reflects light again in the direction of the element antenna 31
And The antenna 3 includes a phase shifter 32 and a short circuit 3 corresponding to the electromagnetic wave S1 received by each of the element antennas 31.
3 and re-radiate from each of the same element antennas 31 via
The main reflector 1, such as a rotating parabolic antenna, is irradiated. The main reflecting mirror 1 converts the received electromagnetic wave S1 into an antenna radiation pattern R
1 (electromagnetic wave S1a), a radiation pattern R2 (electromagnetic wave S1b) different from the pattern R1, and the like.
Here, the array antenna 3 is generally arranged such that the radiation plane P of the electromagnetic wave S1 is substantially perpendicular to the antenna axis A of the double reflector antenna. Antenna axis A is main reflector 1
And the center axis of the beam of the electromagnetic wave S1a of the horn 2. The radiation plane P has a horizontal axis as the u-axis, a vertical axis as the v-axis, and a point that intersects with the antenna axis A as C.

The reflect array antenna 3 has phase shift means for correcting the phase characteristic of the electromagnetic wave S1 radiated from the main reflector 1, and sets each of the phase shifters 32 to an appropriate phase shift amount. The radiation phase of the electromagnetic wave S1 applied to the reflecting mirror 1 is corrected, and the phase of the electromagnetic wave S1 (S1a, S1b, etc.) emitted from the main reflecting mirror 1 is made a flat aperture phase distribution. The amplitude characteristic on the radiation plane P is corrected as shown in FIG. 2B because the amplitude of the electromagnetic wave emitted from the horn 2 is separated from the antenna axis A.
By appropriately designing with a known method so that the number decreases as shown in FIG. 2 (b), it can be easily realized technically and manufacturingly.

FIGS. 3A and 3B are explanatory diagrams for obtaining the phase shift amount of the phase shifter 32 according to the present embodiment. FIG. 3A shows the positional relationship between the horn 2 and the reflect array antenna 3, and FIG.
Excitation distribution (phase), and (c) shows the electrical length compensation phase element antennas 31, (d) the radiating position phase of the horn 2.

The operation of this embodiment will be described with reference to FIGS. 1, 2 and 3.

When the size of the main reflector 1, the curve of the conductor curved surface, and the position of the radiation plane P of the reflect array antenna 3 are determined, a desired antenna radiation pattern R1 (FIG. 2) is obtained.
(A), the radiation pattern R1 of the electromagnetic wave S1a is the beam center
The excitation (electric field) distribution on the radiation plane P corresponding to (the axis is oriented in the direction of the antenna axis A) is as shown in FIG. 2B (amplitude distribution) and FIG. 2C (phase distribution). Conversely, as shown in FIG. 2B, the amplitude distribution on the radiation plane P is reduced as the distance from the antenna axis (C) increases, and the phase distribution on the radiation plane P is changed as shown in FIG.
When the phase is corrected so that the phase is delayed as the distance from the antenna axis (C) increases as shown in (c), a desired antenna radiation pattern R1 with few side lobes is obtained. Here, each of the N element antennas 31 of the array antenna 3 is referred to as 31-1,..., 31-n,.
And These N element antennas 31-1,..., 31
, 31-N are respectively arranged on the radiation plane P, and the electromagnetic waves S1 in each of these element antennas 31
Is on the radiation plane P. Now, an arbitrary element antenna 31-n is arranged at a position (arbitrary angle) θn on the angle θ from the antenna axis A passing through the phase center 21 of the horn 2 (FIG. 3A). Excitation coefficient (phase term) Φn of element antenna 31-n corresponding to antenna radiation pattern R1
Is a phase corresponding to the phase distribution of FIG.
(B).

The angle θ from the phase center 21 of the horn 2 is
The distance l to the element antenna 31-n at the position n is
It is longer than the distance from the center 21 of the radiation plane P, which is the intersection with the antenna axis A, to the center C of the radiation plane P, which is the intersection with the antenna axis A, and it is necessary to correct the phase difference based on this distance difference. There is. The electrical length correction phase of the element antenna 31-n at the position θn on the angle θ from the antenna axis A is Φln (FIG. 3C). Further, the radiation phase αn of the electromagnetic wave S1a with respect to the angle θn at which an arbitrary element antenna 31 is viewed from the phase center 21 of the horn 2 is shown in FIG.
As shown in FIG. The radiation phase of horn 2 is the antenna axis
As it moves away from A, it changes in the fast-moving direction once
After that, it changes in the slow direction. This complex radiation phase change
Is appropriate phase control by the reflect array antenna 3.
Unless there is any, there is a need for precise and complicated mirror correction on the main reflector 1.
It will be important.

Therefore, in order to obtain the excitation distribution (phase) shown in FIG. 3B, the phase shifter 3 connected to the element antenna 31-n is required.
The phase shift amount of 2 (reciprocation) Φpn is given by Φpn = Φn- (Φln
+ Αn), the excitation distribution on the radiation plane P of the reflect array antenna 3 can be set to a desired pattern (FIG. 3B), and the main reflector 1 can be modified without complicated mirror surface correction.
In this double reflector antenna, a desired antenna radiation pattern R1 (FIG. 2A) can be realized.

In this double reflector antenna, an antenna radiation pattern R2 (electromagnetic wave S1) having another beam direction (radiation direction of electromagnetic wave S1) is formed by inclining the phase distribution on radiation plane P of reflect array antenna 3.
1a) and the like can be obtained.

FIGS. 4A and 4B are structural views of the reflect array antenna 3 of the present embodiment, wherein FIG. 4A is a front view, and FIG.
(C) is a sectional view taken along line v1-v2 of FIG.
FIG. 5D is a cross-sectional view taken along line v3-v4 of FIG. 5C, and FIG. 5E is an enlarged rear view of the portion A of FIG.

The reflect array antenna 3 includes N circular patch antennas 41 composed of circular conductors and a dielectric plate 46.
a, a conductor ground plate 45, a dielectric plate 46b, and N microstrip lines 42 composed of conductors are sequentially laminated. Circular patch antenna 41 and dielectric plate 46
a and the ground plate 45 constitute N element antennas 31. Further, each of the microstrip lines 42 and the dielectric plate 46b form N microstrip lines to form N phase shifters 32. Arbitrary element antenna 31-n and phase shifter 32-n at the corresponding position
Is electromagnetically coupled by a coupling slit 45 provided at a corresponding position of the ground plate 45. Microstrip line 4
Each of 3 has one open end and the other end connected to a ground plate 45 by a short-circuit pin 43. This short pin 4
3 and the ground plate 45 constitute the short circuit 33.
The loss of the array antenna 3 due to the phase shifter 32 and the short circuit 33 is slight, and there is little possibility that the amplitude characteristic of the array antenna 3 is changed.

In the reflect antenna 3, the surface of the circular patch antenna 41 has a radiation plane P, and the electromagnetic wave S1 is transmitted and received from the surface of the circular patch antenna 41. Also,
By adjusting the length of the microstrip line 42, the phase shift amount of the phase shifter 32 is set appropriately. By replacing a part of the microstrip line 42 with a variable phase shifter using a PIN diode or the like and electrically controlling the phase of the variable phase shifter, the beam direction of the double reflector antenna can be easily adjusted. Can be controlled.

[0020]

As described above, according to the present invention is, Refureku
Array antenna re-radiates the beam of electromagnetic waves
When directing the mandrel to the antenna axis direction, from the horn
The amplitude of the electromagnetic wave decreases in a direction away from the antenna axis, and the electromagnetic wave is separated from the antenna axis.
Phase correction so that the phase is delayed
Since there is no need to perform precise mirror correction of the main reflector and the sub-reflector having a conductor curved surface, a double reflector antenna having a desired antenna radiation pattern, such as a small side lobe, can be easily and inexpensively manufactured. There is an effect that can be obtained.

This reflect array antenna is
By changing the amount of phase shift of the phase shifting means, the phase of the re-emitted electromagnetic wave can be freely changed, so that the radiation beam direction of the double reflector antenna can be easily changed.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of one embodiment of the present invention.

FIG. 2 is a diagram showing electromagnetic wave radiation characteristics of the present embodiment;
(A) is a desired antenna radiation pattern, and (b) and (c) are electric field distributions (amplitude and phase) on a radiation plane P of the reflect array antenna 3.

3A and 3B are explanatory diagrams for obtaining a phase shift amount of a phase shifter 32 according to the present embodiment, wherein FIG. 3A illustrates a positional relationship between a horn 2 and a reflect array antenna 3, and FIG. 3B illustrates an excitation distribution of the antenna 3; ,
(C) the electrical length correcting phase of the element antenna 31, (d) shows a radiation position phase of the horn 2.

4A and 4B are structural diagrams of the reflect array antenna 3 of the present embodiment, wherein FIG. 4A is a surface view, and FIG. 4B is v1-v of FIG.
FIG. 2C is a cross-sectional view taken along line 2, (c) is an enlarged surface view of part A of (a), (d) is a cross-sectional view taken along line v3-v4 of (c),
(E) is an enlarged back view of part A of (a).

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Main reflection mirror 2 Horn 3 Reflect array antenna 4 Feeding line 21 Phase center 31 Element antenna 32 Phase shifter 33 Short circuit 41 Round patch antenna 42 Microstrip line 43 Short pin 44 Coupling slot 45 Ground plate 46a, 46b Dielectric plate

Claims (4)

(57) [Claims] (1)ElectricA horn that emits magnetic waves,The horn
FromWhile receiving the electromagnetic wave, this electromagnetic wavePrescribed release
Become a fire patternTo re-radiate after phase correction
And a reflect array antenna
And release this electromagnetic wave into space
And a main reflector having an appropriate conductor curved surface to radiate.Double reflector
In antenna, Wherein the reflect array antenna re-radiates the electromagnetic wave;
If the beam center axis of the wave is oriented in the antenna axis direction,
Move the electromagnetic wave from the horn away from the antenna axis
In a state where the amplitude decreases as
Phase lags away from antenna axis
Phase-corrected and re-radiate Characterized by double reflection
Mirror antenna. 2. The reflect antenna receives electromagnetic waves from the horn and re-radiates the electromagnetic waves with a plurality of element antennas, and complements the re-radiated electromagnetic waves.
Double reflector antenna according to claim 1, further comprising a phase shifter of each respective corresponding prior Symbol antenna elements positively to. Wherein the element antenna, the sub-reflector antenna according to claim 2, characterized in that the circular patch antenna. 4. The reflect array antenna according to claim 1, wherein
A plurality of patch antennas that receive the electromagnetic wave from the horn and re-emit the electromagnetic wave, a microstrip line connected to each of the patch antennas via a coupling slot, and a microstrip line connected to one end of the microstrip line, respectively. The double reflector antenna according to claim 1, further comprising a short circuit.