JPS6327908B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention utilizes two mutually orthogonal polarizations (for example, vertical and horizontal polarizations in the case of linear polarization, and left and right-handed circular polarizations in the case of circular polarization). The present invention relates to an antenna power feeding device in a communication system, and particularly to an antenna power feeding device that compensates for cross-polarized waves generated due to the influence of radio wave propagation paths.

There is a frequency reuse method in which separate signals are placed on two mutually orthogonal polarized waves of the same frequency, and a single frequency is used for two channels, and is also used in satellite communications. What is important with this method is to sufficiently compensate for cross-polarized waves that occur due to the influence of propagation paths, etc.
Devices that have been proposed for this purpose include, for example, ``Cross Polarization Compensation System'' published in Japanese Patent Laid-Open No. 51-115717 (hereinafter referred to as prior document).

FIG. 1 is a block wiring diagram showing the system disclosed in the prior literature, in which 1 is a transmitting and receiving antenna, 2 is a transmitting and receiving duplexer, 3 and 13 are each a 180 degree phase difference plate,
4 and 14 are 90-degree phase difference plates, 5 is a receiving side orthogonal polarization splitter, 15 is a transmission side orthogonal polarization splitter,
6, 7, 16, 17 are amplifiers, 8, 9,
24 and 25 are branch circuits, 30 and 31 are receiver couplers, 18 and 19 are transmitter couplers, 20, 22, 26 and 28 are variable attenuators, and 21, 23, 27 and 29 are respectively variable attenuators. It is a variable phase shifter.

Two mutually orthogonal polarized waves undergo different attenuations, different phase delays, and different polarization plane rotations in the propagation path, so the radio waves received by antenna 1 generally have an anti-rotating relationship with each other. It becomes an elliptically polarized wave. FIG. 2 is a diagram schematically showing the polarization plane of radio waves for explaining the present invention, in which a shows an example of the polarization plane of the radio waves input to the antenna 1, and V ₀ and H are in a counter-rotating relationship with each other. ₀ indicates elliptical polarization. In FIG. 1, each of the retardation plates 3, 13, 4, and 14 has a structure that allows it to rotate around the direction of propagation of electromagnetic waves (that is, the direction of the length of the waveguide) as an axis. It is well known that by adjusting the retardation plates 3 and 4, the polarized wave shown in Figure 2a can be converted into elliptically polarized waves _V1 and _H1 whose long axes are orthogonal, respectively, as shown in Figure 2b. It is. In other words, at the input end of the orthogonal polarization splitter 5, the polarization plane of the radio wave is as shown in Fig. 2b.
The state shown in is reached. The x-direction components of V ₁ , H ₁ and y
If the directional components are V _1x , H _1x , V _1y , and H _1y , the voltage E _y at the input terminal of the amplifier 6 is E _y = V _1y + H _1y (1), and the voltage E _x at the input terminal of the amplifier 7 is E _x = V _1x + H _1x ...(2).

(In order to simplify the explanation, the amplification degree of the amplifier is normalized to 1. The same applies hereinafter.) Branch circuits 8 and 9 each divide the input into two equal parts and output it, and a variable attenuator 28 and a variable phase shifter 29 If α ₁ is _the transfer function of the receiving transfer circuit composed of are respectively S _y = 1/2 [V _1y + H _1y −α ₁ (V _1x + H _1x )] … (3) S _x = 1/2 [H _1x + V _1x − α ₂ (H _1y + V _1y )] … …(4) becomes. Since V _1y > V _1x and H _1x > H _1y , adjust α ₁ and α ₂ to obtain H _1y = α ₁ H _1x ……(5) V _1x = α ₂ V _1y ……(6) , in S _y of equation (3), the component of H ₁ becomes zero, and in equation (4),
In S _x , the component of V ₁ can be made to be zero. That is, each signal can be detected by removing the influence of crossed polarization components.

On the other hand, on the transmitting side, the carrier wave of the first signal is input to the branch circuit 24, and the carrier wave of the second signal is input to the branch circuit 25, and when these carrier waves are transmitted with mutually orthogonal polarization, reception is possible. A cross-polarized wave sufficient to cancel the cross-polarized wave generated at the point is given in advance and transmitted from the antenna 1. The circuit shown in FIG. 1 has been explained in detail in the prior literature, so further description will be omitted, but the disadvantage of the circuit shown in FIG. 20,2
Two lines: 1, 22, 23 and 26, 27, 28, 2
Since two circuits (9) are required, the circuit configuration is complicated and large, which makes it difficult to install and reduces reliability. Also between amplifiers 6 and 7 and 1
Another drawback of the circuit shown in FIG. 1 is that the unbalanced amplitude and phase characteristics for the two systems, dextrorotation system and left-rotation system between 6 and 17, intersect and affect the degree of polarization improvement.

The purpose of this invention is to eliminate the above-mentioned drawbacks by simplifying the circuit configuration by making the transmission circuit into one system on each of the transmission side and the reception side, and by providing the amplifier on the transmission side at a stage before the transmission circuit and the coupler. Therefore, the influence of unbalanced amplitude and phase characteristics on the two systems, dextrorotation system and left-rotation system, is removed, and the drawings will be described in detail below.

FIG. 3 is a block diagram showing one embodiment of the present invention, and the same reference numerals as in FIG. 1 indicate the same or corresponding parts and perform the same operations, so redundant explanation will be omitted.
32 and 33 are transmitting amplifiers, respectively, and 1 in Fig. 1.
6 and 17, but compared to the connection shown in Figure 1, it is located before the circuits 18, 19, 22, 23, etc., so there is a problem with the unbalanced amplitude and phase characteristics for the two systems, dextrorotation system and left rotation system. It will never be.

Also in this invention, the plane of polarization of the radio wave input from the receiver connection part of the transmitter/receiver splitter 2 to the 90-degree phase difference plate 4 is as shown in FIG. By adjusting the retardation plate device consisting of the cascade connection of 4 and 180-degree retardation plate 3, one elliptically polarized wave is shifted in the x-axis direction as shown as V ₂ and H ₂ in Fig. 2c. Convert to linearly polarized wave with polarization plane. The fact that this conversion is possible can be easily understood from the fact that rotating the 90-degree retardation plate 4 changes the polarization from linear to circular polarization, and rotating the 180-degree retardation plate 3 rotates the polarization plane of the linearly polarized wave. It is.

Therefore, corresponding to equations (1) and (2) for Fig. 2 b, the following equations hold true for Fig. 2 c: E _y = V _2y ... (7) E _x = H ₂ + V _2x ... (8) , E _y are amplified by the amplifier 7 and a carrier wave containing no H component is obtained from one output terminal of the branch circuit 9 as S _y = 1/2E _y = 1/2V _2y (9). In addition, the output 1/2E _2y = 1/2V _2y from the other output terminal of the branch circuit 9 is converted to α ₃ V _2y by the receiving side transfer circuits 28 and 29, and is combined with the output shown in equation (8) by the combiner 30. Then S _x = E _x −α ₃ V _2y = H ₂ +V _2x −α ₃ V _2y
...(10), but if the transfer function α ₃ is adjusted so that α ₃ V _2y = V _2x ...(11), S _x = H ₂ ...(12), and the carrier wave does not contain the V component. get.

That is, according to the present invention, the two sets of transmission circuits 26, 27 and 28, 29 required in the connection shown in FIG. It gets easier. Note that the amplifier 7 in Fig. 3 is as shown in equation (7).
Since only the V ₂ component is amplified, amplifier 7 in Figure 1
There is no need to worry about the imbalance between the two systems, the dextrorotation system and the left rotation system, as in the case of FIG.

The operation of the transmitter circuit in FIG. 3 can be easily understood from the operation of the transmitter circuit in FIG.
The sets of transmission circuits become one set in the connection shown in FIG.

FIG. 3 is a block diagram showing one embodiment of the present invention, which is mainly used in the microwave field and is therefore often constructed from a waveguide circuit. Fig _. 4 is a block diagram showing an example of the circuit shown in Fig. 3 configured with _a waveguide circuit. vessel, OMJ
is a group splitter, RJ is a circular waveguide rotary joint, π/2 is a 90-degree retardation plate, π is a 180-degree retardation plate, OMT is an orthogonal polarization splitter, and DC is a directional coupling. D indicates a non-reflection termination, HYB indicates a hybrid circuit, and CWG indicates a circular waveguide. However, although the part with the rotary joint RJ is a circular waveguide, it is not marked with a CWG symbol.

TM ₀₁ 40 and OMJ41, 42 constitute the transmitter/receiver duplexer 2, π/243, 45, π44 constitute the transmission circuit 28, 29, π/246, 4
8 and π47 constitute the transmission circuits 22 and 23. Since the other circuits in FIG. 4 are obvious from the description of the circuits in FIGS. 1 and 3, their explanations will be omitted.

As described above, according to the present invention, it is possible to obtain an antenna feeder that compensates for crossed polarization using a simple circuit.

[Brief explanation of drawings]

FIG. 1 is a block wiring diagram showing the system disclosed in the prior literature, FIG. 2 is a diagram schematically showing the polarization plane of radio waves, FIG. 3 is a block wiring diagram showing an embodiment of the present invention, and FIG. This figure is a block diagram showing an example of the configuration of the circuit shown in FIG. 3. In these figures, 1 is a transmitting and receiving antenna,
2 is a transmitting/receiving duplexer, 3 and 13 are each 180 degree retardation plate, 4 and 14 are each 90 degree retardation plate, 5 and 1
5 are orthogonal polarization splitters, 6 and 7 are receiving amplifiers, 9 and 18 are branch circuits, and 2
2 and 28 are variable attenuators, 23 and 29 are variable phase shifters, 19 and 30 are couplers, and 32 and 33 are transmitting amplifiers.
Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Scope of Claims] 1. In an antenna feeding device that couples a transmitting/receiving antenna to a transmitter and a receiver for transmitting and receiving two elliptically polarized electromagnetic waves having the same frequency and opposite rotation, the antenna connecting portion and the receiving a transmitting/receiving duplexer having a transmitter connecting part and a transmitter connecting part and separating the coupling between the antenna and the receiver from the coupling between the antenna and the transmitter; and an output from the receiver connecting part of the transmitting/receiving duplexer. a receiving-side retardation plate device that inputs the input signal and converts one of two elliptically polarized electromagnetic waves having an anti-rotating relationship contained in the input into a linearly polarized electromagnetic wave having a predetermined plane of polarization; , is connected to the output terminal of this receiving side phase difference plate device, and an electromagnetic wave having the same polarization plane as the linearly polarized electromagnetic wave is sent to a first output terminal, and an electromagnetic wave having a polarization plane perpendicular thereto is sent to a second output terminal. a receiving-side orthogonal polarization splitter that outputs each, and first and second amplifying outputs from the first and second output terminals of the receiving-side orthogonal polarization splitter, respectively;
a receiver amplifier, a receiver transfer circuit that provides adjustable attenuation and adjustable phase delay to a portion of the output from the second receiver amplifier, an output of the receiver transfer circuit and the first receiver amplifier; a receiving-side combiner for combining the outputs of the receiving-side amplifiers of the first and second signals; and first and second receivers for amplifying the carrier wave of the first signal and the carrier wave of a second signal having the same frequency as the carrier wave of the first signal, respectively. a transmission-side amplifier, a transmission-side transmission circuit equivalent to the reception-side transmission circuit, a branch circuit that inputs a part of the output of the first transmission-side amplifier to the transmission-side transmission circuit, and the second transmission circuit. A transmitting side coupler that combines the output of the side amplifier and the output of the transmitting side transmission circuit, and a transmitting side coupler that has a structure equivalent to the receiving side orthogonal polarization splitter, and the receiving side orthogonal polarization splitter is an input device. a transmitting-side orthogonal polarization splitter in which the output terminals are exchanged, and the output of the first transmitting-side amplifier is connected to a first input terminal, and the output of the transmitting-side coupler is connected to a second input terminal; a transmitting-side retardation plate device having a structure equivalent to the receiving-side retardation plate device and connected between the transmitting-side orthogonal polarization splitter and the transmitter connection portion of the transmitting/receiving duplexer; An antenna power feeding device characterized by: 2 The receiving side phase difference plate device changes the phase of one of the two orthogonal polarized waves constituting the two elliptically polarized electromagnetic waves having a counter-rotating relationship to each other by 90 degrees with respect to the phase of the other polarized wave. A 90 degree retardation plate that can be changed in degree,
A 180 degree phase difference plate that can change the phase of one of the two orthogonal polarized waves by 180 degrees with respect to the phase of the other polarization is connected in cascade, and these phase plates are connected to the electromagnetic wave. 2. The antenna power feeding device according to claim 1, wherein the antenna power feeding device is configured to have a structure that can rotate around the traveling direction of the antenna. 3. The antenna power feeding device according to claim 1, wherein the receiving side transmission circuit includes a variable attenuator and a variable phase shifter connected in series to the variable attenuator.