JPH0546510B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a self-tracking feeding system for an antenna that accurately points in the direction of arrival of radio waves with a quick response.

Conventionally, in order to accurately point an antenna in the direction of arrival of radio waves, when the direction of the antenna deviates from the direction of arrival of radio waves, a higher-order mode wave excited in the radiation feeding part of the antenna is used to generate a direction error signal. A self-tracking system that automatically drives the antenna to counteract this problem has been put into practical use. Among these self-tracking methods using higher-order mode waves, in the case of a power supply device equipped with two mode detectors, it is possible to detect all polarizations of incoming radio waves, from linear polarization to circular polarization. Since it is easy to obtain a direction error signal from this method, it is often used.

To explain such a conventional example with reference to the graph in FIG. 1 showing the coordinate relationship between the arriving wave and the tracking antenna, θ is the angular difference between the direction of the antenna H and the source of the arriving wave, and the orthogonal component of the direction error is the following: Therefore, E _H =
θcosφ, E _V =θsinφ. The arriving wave P is expressed as follows: P=K(ejωt+be−jωt)ejγ (1) and is a generalized arbitrary polarized wave. In equation (1), K is a constant that normalizes the voltage of the arriving radio wave, and includes 1/√2 (1+ ² ). b indicates the elliptical polarization coefficient; when b=0, it is a right-handed circularly polarized wave, when b=1, it is a linearly polarized wave, and when b=∞, it is a left-handed circularly polarized wave. γ represents the inclination angle representing the long axis direction of the arriving radio wave.

FIG. 2 is a block diagram showing the configuration of a conventional self-tracking feed system suitable for the above-mentioned tracking antenna. In this figure, 1 is the primary radiator of the antenna, 2 is the TE゜₀₁ mode coupler, and 3 is the antenna primary radiator.
TM゜₀₁ mode coupler, 4 is a 90 degree phase shifter, 5 is a synthetic hybrid, 6 is a switch, 7-1 is a 180 degree polarizer, 7-2 is a 90 degree polarizer, 8
-1 and 8-2 are polarizers 7-1 and 7
9 is a polarization splitter, 10-1 and 10-3 are circularly polarized wave generators, and 10-2 is a 180 degree polarizer.
Now, when the direction of the arbitrary arriving radio wave deviates from the axial direction of the primary radiator 1, the mode couplers 2 and 3 have voltages due to higher-order modes as shown in equations (2) and (3), respectively, V ₁ = k ₁ Kθ{sin(ωt+γ−φ) −bsin(ωt−γ+φ)} …(2) V ₂ =k ₂ Kθ{cos(ωt+r−φ) +bcos(ωt−r+φ)} …(3) is detected . Here, by the phase shifter ₄ , −
When a phase shift of 90 degrees is given and the amplitudes of k ₁ and k ₂ are made equal, k is the value and synthesized by the hybrid 5, the in-phase terminal 5-1 and anti-phase terminal 5-2 at the output have the following: The following voltages are obtained, respectively: V _H =kKθsin(ωt+r−φ)…(4) V _E =−kKθbsin(ωt−r+φ)…(5).

On the other hand, radio waves in fundamental wave mode (TE゜₁₁ mode) are transmitted to polarizer 7-1 with rotation angle r ₂ and
It passes through the polarizer 7-2 of _r1 and is received by the polarization splitter 9, which is used as a reference signal. This reference signal is applied to the X-axis component terminal 9-1 and the Y-axis component terminal 9-2 of the deflection wave device 9, respectively, with output voltages expressed by equations (6) and (7), E _H =C・KAsinW ₁ +CKb・BsinW ₂ …(6) E _Y =CKBsinW ₁ −CKb・AsinW ₂ …(7) is obtained. Here, C is a constant K is a constant including 1/√2 ( ² ) explained in equation (1) A = cosr ₁ + sinr ₁ B = cosr ₁ - sinr ₁ W ₁ = ωt + r-2r ₂ + r ₁ W ₂ = It represents ωt−r+2r ₂ −r ₁ . Conventionally, since this reference signal passes through the same route as the communication signal, it has been put into practical use on the assumption that the arriving wave is linearly polarized, right-handed, or left-handed circularly polarized. For example, right-handed circularly polarized wave,
That is, when b=0, r ₁ is fixed at 45°. In this case, E _X =CK・√2・sin(ωt+r−2r ₂ +π/4) E _Y =0. If r ₂ = constant, the phase variation term of _E
, and can be converted as shown in equation (8) below: _EX = C'Ksin (ωt+r) (8). Using the signal expressed by equation (8) as a reference signal, this reference signal and (4)
By using two multipliers, a DC component signal proportional to θsinφ and θcosφ can be obtained from the signal expressed by the equation. In exactly the same way, b=∞,
In other words, even in the case of left-handed circularly polarized waves, the same signal as in equation (8) and (5)
θsinφ and θcosφ are obtained from the signals expressed by the equations. Also, when b=1, that is, when linearly polarized wave
Since r ₁ =0 is set and the rotation angle of the polarizer 8 is driven so that 2r ₂ =r, E _X or E _Y becomes C'·Ksinωt.

On the other hand, the error signal given by equations (4) and (5) is
Therefore, in order to cancel the inclination angle r of the arriving polarized wave, the circularly polarized wave generator 10-1, the 180 degree polarizer 10-2, and the circularly polarized wave generator 10-3 It uses a phase shifter configured. This phase shifter converts the input wave into a circularly polarized wave generator 1
After being converted once into a circularly polarized wave by 0-1, it is input to a 180 degree phase shift type polarizer 10-2, and then converted again to a linearly polarized wave by a circularly polarized wave generator 10-3. At this time, the amount of phase shift of the output wave is the polarizer 10-
2, the tilt angle r can be canceled out by driving the polarizer 10-2 with the geared motor/angle detector 8-1 of the drive section.

However, in the above-mentioned conventional self-tracking power feeding system, since the incoming polarized wave is assumed to be linearly polarized wave, right-handed circularly polarized wave, or left-handed circularly polarized wave, the arriving polarized wave becomes elliptically polarized wave. Then, since the reference signal includes a varying phase term, independent angular error signals for θcosφ and θsinφ cannot be obtained. Another drawback is that the circuit configuration of the reference signal must be changed depending on the type of arriving polarized wave.

An object of the present invention is to eliminate the above-mentioned conventional drawbacks and to provide a complete self-tracking power supply system that can be used for all kinds of incoming polarized waves without changing the circuit configuration and without crosstalk.

According to the present invention, an error signal due to two different high-order mode waves and a fundamental wave mode among the high-order mode waves excited in the antenna radiation feeding section according to the deviation of the reception antenna direction axis with respect to the direction of arrival of radio waves. In a self-tracking feed system that tracks the direction of the antenna by comparison with a reference signal obtained from 90 degree phase shifter 14
is combined with the output of the other higher-order mode coupler 13 via the hybrid 15, and the combined output is separated into a right-handed circularly polarized wave component and a left-handed circularly polarized wave component,
comprising error signal generating means for transmitting an error signal generated by the higher-order mode wave to a receiver for tracking control;
A first rotating 180-degree polarizer 16, a first rotating 90-degree polarizer 17, and a first orthogonal polarization splitter 20 are connected in series to the two higher-order mode couplers 12 and 13. ; Said orthogonal polarization splitter 2
comprises low noise amplifiers 21, 23 and directional couplers 22, 24 directly connected to the two outputs of 0;
The two signals extracted from the directional couplers 22 and 24 are guided to a second orthogonal polarization splitter 25; directly connected to the orthogonal polarization splitter 25, a second rotating 180 degree polarizer 26 and a third comprising an orthogonal polarization demultiplexer 27;
The two outputs of the third orthogonal polarization splitter 27 are guided to a fourth orthogonal polarization splitter 29 via a hybrid 28; directly connected to the orthogonal polarization splitter 29, a second 90 degree polarizer is connected. 30, third rotating 180 degree polarizer 31, third 90 degree polarizer 35 and fifth
A reference signal generating means is provided with orthogonal polarization splitters 36 in series one after another, and sends two outputs of the orthogonal polarization splitters 36 as a reference signal obtained from the fundamental mode wave to the tracking control receiving section. , and the first rotating 90 degree polarizer 17 and the first,
Second and third rotating 180 degree polarizers 1
6, 26, and 31, respectively, by controllably driving the first
The rotating 90 degree polarizer 17 and the first, second,
and a third rotating 180 degree polarizer 16, 2
Letting the rotation angles of 6 and 31 be r ₁ , r ₂ , r ₃ , r ₄ respectively, _{2r 3 =} r ₁ and 2r ₄ according to the determined r 1 and r ₂
2nd and 3rd rotation type so as to satisfy =r ₁ −2r ₂
A self-tracking power supply device characterized by having a function of setting 180-degree polarizers 26 and 31 is obtained.

Next, examples of the self-tracking power feeding system according to the present invention will be described with reference to the drawings.

FIG. 3 is a block diagram showing the structure of an embodiment according to the present invention. According to this example:
An incoming radio wave is received by a primary radiator 11 of the antenna, and two higher-order mode outputs are extracted by a TE ₀₁ mode coupler 12 and a TM ₀₁ mode coupler 13, respectively. One of them is given a phase shift of 90 degrees by a phase shifter 14, and after making both outputs have the same amplitude, they are combined by a hybrid 15. The output of this hybrid 15 is extracted separately into a voltage V _H due to the right-handed circularly polarized wave component and a voltage VE due to the left-handed circularly polarized wave component given by the above equations (4) and (5 ₎ .

On the other hand, in order to obtain signals used for communication that do not include interference components with respect to arriving waves of arbitrary polarization, a rotatable 180 degree phase shift type polarizer 16 and a 90 degree phase shift type polarizer 17 are used. is provided in the communication signal passage path. In this case, since the reference signal also passes through the same path as the communication signal path, the rotation angle of the polarizer 17 is r ₁ and the rotation angle of the polarizer 16 is
If r ₂ , the orthogonal output terminal 2 of the orthogonal polarization splitter 20
0-1 and 20-2, _the signal voltages _E These signal voltages are connected to low noise amplifiers 21 and 23, respectively.
After being amplified by , the signals are branched by directional couplers 22 and 24 , one of which is guided to output terminals 22 - 1 and 24 - 1 , and the other of which is provided to an orthogonal polarization splitter 25 . The output of the orthogonal polarization splitter 25 is detected by the polarization splitter 27 via a 180 degree polarizer 26 which can be simultaneously rotated by a control system. _The two _outputs detected _{here are E ′} +CKb(Asin2r
₃ +Bcos2r ₃ ) sinW ₂ …(9) E′ _Y = CK (Asin2r ₃ −Bcos2r ₃ ) sinW ₁ −CKb (Acos2r ₃ −B
sin2r ₃ ) sinW ₂ …(10) becomes the converted signal. Here, r ₃ is the rotation angle of the polarizer 26, C, K, b, A, B,
W ₁ and W ₂ are respectively given when the rotation angles of polarizers 17 and 16 are given as r ₁ and r ₂ , respectively.
This is the same expression used in equation (7).

Now, in the above equations (9) and (10), if 2r ₃ =r ₁ is set, the respective output voltages become equations (11) and (12). _{These signal voltages} are divided by the polarization splitter ₂₇ into orthogonal _outputs , E _″ Signals obtained from equations (11) and (12) above
E″ _X and E″ _Y are synthesized by hybrid 28. The outputs are signal voltages Ea and Eb as shown in equations (13) and (14), respectively, and the output lines 28a and 28a are respectively
and 28b. These voltages serve as reference signals for each of the right-handed and left-handed circularly polarized components, which do not change depending on the rotation angle r ₁ of the polarizer 17.

Ea＝C′KsinW ₁ …(13) Eb＝C′K・bsinW ₂ …(14) The above voltages Ea and Eb are applied to the orthogonal polarization splitter 29, and the two After simultaneously passing through a phase shifter consisting of 90 degree polarizers 30 and 35 and a rotatable 180 degree polarizer 31 sandwiched between them,
The signals are separated again by the orthogonal polarization demultiplexer 36. The output lines 36a and 36b of the orthogonal polarization demultiplexer ₃₆ each have (1
5) and ( ₁₆ ), the following signals appear: E'a=-C'Kcos( _W1-2r4 )...(15) E'b=C'Kbcos( _W2 + _2r4 )...(16).

Here, in the above equations (15) and (16), W ₁ =
Since ωt+r−2r ₂ +r ₁ and W ₂ =ωt−r+2r ₂ −r ₁ , by giving the polarizer 31 a rotation angle r ₄ such that 2r ₄ =r ₁ −2r ₂ , (15) and (16) are obtained. The voltage signals of the equations are respectively E″a=−C′Kcos(ωt+r)…(17) E″b=C′Kbcos(ωt−r)…(18). These two signal voltages are used as reference signals, and these reference signals are supplied to the tracking receiver together with the error signals given by equations (4) and (5). The tracking receiver uses four multipliers, and as a result of multiplication, the DC component of the output signal is V ₁ = C″K ² θsinφ …(19) V ₂ = C″K ² θcosφ …(20) V ₃ =C″K ² b ² θsinφ…(21) V ₄ =C″K ² b ² θcosφ…(22) are obtained. Among these DC signals, the polarity of the V ₃ and V ₄ signals is swapped to create V ₁ +V ₃ and V ₂ +V _4.
If K is a constant proportional to 1/√2 (1+ ² ), it is possible to obtain Vy=Cθsinφ and Vx=Cθcosφ, which do not include the elliptical polarization coefficient b of the arriving wave.

In addition, in FIG. 3, the part indicated by the broken line shows the drive control system of the polarizer, of which:
The gear/motor 19 receives the signal _C2 from the control section and drives the 90 degree polarizer 17.
The 180 degree polarizer 26 is connected to the gear/motor 19 and is connected to the gear/motor 19 through a reducer 32 that reduces the rotation angle to 1/2.
to drive. Further, the gear/motor 18 drives the 180-degree polarizer 16 in response to a signal _C1 from the control section. The drive circuit 33 receives the controlled rotation angle r ₂ of the 180-degree polarizer 16 obtained from the gear/motor 18 and the controlled rotation angle r ₁ of the 90-degree polarizer 17 obtained from the reducer 32, and calculates (2r ₂ −
r)/2 rotation. Gear/motor 34 operates in conjunction with drive circuit 33 to drive 180 degree polarizer 31.

In the above embodiment, the circuit through which the communication signal and the reference signal pass is conventionally implemented.
The explanation has been given using an example where a 180 degree polarizer and a 90 degree polarizer are provided, but if there is no 90 degree polarizer, that is, if there is no 90 degree polarizer 17 in FIG.
5. The polarizer 26 and polarization splitter 27 are no longer needed. In addition, if the 180-degree polarizer 16 is not used, the 90-degree polarizer 17 is used fixed at 45 degrees, so the elements of the orthogonal polarization demultiplexer 29, polarizers 30, 31, 35, and orthogonal polarization demultiplexer 36 is no longer necessary, but the operating principle remains exactly the same.

In addition, in the above embodiment, two higher-order mode outputs are extracted by the TM ₀₁ mode and TE ₀₁ mode coupler, but a pair of orthogonal mode outputs are extracted.
Even if a TE ₂₁ mode coupler is used, the voltage due to higher-order modes similar to equations (2) and (3) above, V' ₁ = k' ₁ Kθ {cos (ωt + r + φ) + bcos (ωt − r − φ)} V′ ₂ =k′ ₂ Kθ{sin(ωt+r+φ) −bsin(ωt−r−φ)} is detected. And the phase shifter 4 in FIG.
gives a 90° phase shift to V′ ₂ , and the above k′ ₁ and k′ ₂
If the value when the amplitudes of
and 5-2, the following voltages are obtained, respectively: V' _H =kKθcos(ωt+r+φ) _V′E =kKθbsin(ωt−r−φ). Therefore, using the reference signals of equations (17) and (18) in the above embodiment, voltages with the same amplitude as the DC component expressed by equations (19) to (22) can be generated using four multipliers. Therefore, by performing polarity conversion and composing, Vy=Cθsinφ and Vx=C
θcosφ can be obtained.

As is clear from the above description, according to the present invention, the 180
Independently from the operations of the 90-degree polarizer and the 90-degree polarizer, it is possible to obtain direction error voltages that are necessary for antenna self-tracking and are completely orthogonal and do not interfere with each other. There is no need to change the circuit configuration for waves,
Therefore, the effects of increasing the flexibility of the system and improving economic efficiency are significant.

[Brief explanation of the drawing]

Fig. 1 is a graph showing the coordinate relationship between the arriving wave and the tracking antenna, Fig. 2 is a block diagram showing a configuration example of a conventional self-tracking power feeding system, and Fig. 3 is a block diagram showing the configuration of an embodiment according to the present invention. It is. In the figure, 11 is the primary radiator of the antenna, 1
2 is a TE ₀₁ mode coupler, 13 is a TM ₀₁ mode coupler, 14 is a phase shifter, 15 is a hybrid, 16 is a rotating 180 degree polarizer, 17 is a 90 degree polarizer, 18, 19, 34 are gears/motors, 20
is an orthogonal polarization splitter, 21 and 23 are low noise amplifiers, 2
2 and 24 are directional couplers, 25 is an orthogonal polarization splitter,
26 is a rotating 180 degree polarizer, 27 is an orthogonal polarization demultiplexer, 28 is a hybrid, 29 is an orthogonal polarization demultiplexer, 30 and 35 are 90 degree polarizers, 31 is a rotation 180 degree polarizer, 32 is a speed reducer, 33 3 is a drive circuit, and 36 is an orthogonal polarization splitter.

Claims (1)

[Claims] 1. An error signal caused by two different higher-order mode waves among the higher-order mode waves excited in the antenna radiation feeding section according to the deviation of the receiving antenna direction axis with respect to the arrival direction of the radio wave, and a fundamental wave. In the self-tracking feed system that tracks the direction of the antenna by comparing it with a reference signal obtained from the mode, each of the two higher-order mode waves is extracted.
The output of one of the two high-order mode couplers is hybridly combined with the output of the other high-order mode coupler via a 90 degree phase shifter, and the combined output is an error signal generating means for separating a right-handed circularly polarized wave component and a left-handed circularly polarized wave component and sending the error signal to a receiver for tracking control as an error signal due to the higher-order mode wave; the two higher-order mode couplers; A first rotating 180 degree polarizer, a first rotating 90 degree polarizer, and a first orthogonal polarization demultiplexer are connected in series; directly connected to the two outputs of the orthogonal polarization demultiplexer, respectively. equipped with a low noise amplifier and a directional coupler;
The two signals extracted from the directional coupler are guided to a second orthogonal polarization demultiplexer; a second rotating 180 degree polarizer and a third orthogonal polarization demultiplexer are directly connected to the orthogonal polarization demultiplexer. directing the two outputs of the third orthogonal polarization splitter to a fourth orthogonal polarization splitter via a hybrid;
a third rotary 180 degree polarizer, a third 90 degree polarizer, and a fifth orthogonal polarization demultiplexer, which are successively connected in series;
reference signal generating means for transmitting two outputs obtained from the fundamental mode wave to the tracking control receiving section as a reference signal obtained from the fundamental mode wave; By controllably driving the rotation drive units provided in the third rotary type 180 degree polarizer, the first rotary type 90
The rotation angles of the 180-degree polarizer and the first, second, and third rotating 180-degree polarizers are γ ₁ ,
γ ₂ , γ ₃ , γ ₄ according to the determined γ ₁ and γ ₂
A self-tracking power feeding device characterized by having a function of setting the second and third rotating 180-degree polarizers so as to satisfy 2γ ₃ =γ ₁ and 2γ ₄ =γ ₁ −2γ ₂ .