JPH0232281A - High frequency signal processing circuit for target tracking device - Google Patents

Abstract

PURPOSE:To reduce the size and weight of the tracking device by using a plane antenna by providing at least four patch antennas, three hybrid circuits, a circuit which connects them, and three microstrip-coaxial converter. CONSTITUTION:The device consists of the patch antennas 1a-1d corresponding to a four-horn type horn, output terminals 3a-3c, for a sum signal SIGMA, a difference signal DELTAAz in a depression-directional plane, and a difference signal DELTAEl in an elevation-directional plane which are generated by rat race circuits 2a-2b corresponding to the hybrid circuits, coaxial outputs 4a-4c, and a signal processing circuit 5. The difference signals become zero in the peak direction of the sum signal and are inverted in phase in the left and right directions from the front, and the direction of an error can be detected by comparing the amplitudes and phases of the difference signals DELTAAz and DELTAEl to obtain the device which can obtain a tracking error signal for directing the antenna to a target. For example, this device is fitted on the reverse surface of the sub-reflecting mirror of, for example, a Cassegrain antenna to easily pickup a target such as an artificial satellite.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a high frequency signal processing circuit in a tracking antenna device for an earth station antenna for satellite communication.

[Conventional technology]

Figure 4 shows, for example, "Array Antenna J 5.8" in the document "Antenna Engineering Handbook, IEICE Report, Ohmsha".
．． A high frequency signal processing circuit called a so-called comparator is shown in a conventional target tracking device using a four-horn monopulse tracking method shown in 3-Monopulse Power Supply Circuit, P, 225, and FIG. 5 shows its horn section.

In both figures, la, lb, kc, and ld are horns of the same shape, 2a is the first hybrid (HYBl), 2b is the second hybrid (HYB2), 3a, 3b, and 3c are monopulse outputs, and 3a is the The sum signal output of the outputs of the four horns, 3b is the difference signal output in the Az plane (depression angle direction),
3c is a difference signal output in the E1 plane (elevation angle direction).

Next, the operation will be explained.

The radio waves received by horns A, B, C, and D are HYBL (
There are four composite outputs: A±B) and (C±D), which are further synthesized by HYB 2, resulting in (A+B)+(C+D),
In other words, the sum signal (Σ) of the four horns is output from the output port 3a.
Therefore, (A+B)-(C+D), that is, the difference signal (ΔAz) in the Az plane, is transmitted from the output port 3b and further from (A-B
)+(C-D)mi(A+C)-(B+D), that is, the difference signal ΔEl within the 81 plane is obtained from the output port 3c.

-i, when using such a four-horn monopulse tracking method, a pyramidal horn with a square aperture as shown in Figure 5 is used as the horn, and a three-dimensional circuit (waveguide circuit) using Magic-T is used as the HYB. ) to construct a high-frequency signal processing circuit.

[Problem to be solved by the invention]

The high-frequency signal processing circuit of a target tracking device using the conventional 4-horn monopulse tracking method is configured as described above, so it is difficult to make it smaller and lighter. When used as an antenna device or for similar purposes on the back of a folding antenna, there are problems such as the impossibility of attachment.

This invention was made to solve the above-mentioned problems, and uses a flat antenna to create a small and lightweight 4
The purpose of this study is to obtain a high-frequency signal processing circuit that utilizes the principle of the single-monopulse tracking method.

[Means to solve the problem]

The high frequency signal processing circuit of the target tracking device according to the present invention includes:
It consists of four patch antennas using microstrip lines, three rough trace circuits using microstrip lines, and a coaxial output circuit that converts the output of the rough trace circuits to coaxial.

[Effect]

In the four-horn monopulse tracking high-frequency signal processing circuit according to the present invention, the difference signal becomes zero in the direction of the peak of the sum signal, as shown in FIG. The phase is reversed in the left and right direction from the front, and ΔAz, ΔEI! By comparing the amplitude and phase of the signals, the direction of the error can be detected, and a tracking error signal for directing the antenna toward the target can be obtained. In particular, the error signal ΔAz normalized by the sum signal Σ
, ΔEl change linearly near the main beam of the sum signal.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

1 and 2 show a high frequency signal processing circuit in a tracking antenna device for target tracking according to an embodiment of the present invention, and in the figures, la and lb.

lc and Id are four patch antennas corresponding to four horns, 2a is the first hybrid, 2b is the second hybrid, 3a, 3b, and 3c are the sum signal Σ and the difference signal ΔA, respectively.
z is an output terminal for the difference signal ΔEl, and 4a, 4b, and 4c are coaxial outputs. 5 is a monopulse tracking high frequency signal processing circuit using a microstrip line having the above-mentioned four patch antennas, three rough trace circuits and three coaxial outputs, and 51 is a ground plane. FIG. 3 shows the conversion from a microstrip line to a coaxial line.

If such a packaged monopulse signal processing circuit is attached to the back surface of the sub-reflector 6 of the Cassegrain antenna, as shown in FIG. 8, for example, targets such as satellites can be easily captured.

FIG. 6 is a configuration diagram showing the principle and appearance of this invention.
a, lb, lc, ld are horns A, B, C, in Fig. 5.
Patch antenna corresponding to D, 2a is a rough trace circuit and corresponds to the first hybrid HYB1, 2b is also a rough trace circuit and corresponds to the second hybrid HYB2
This corresponds to Although 2C can in principle be replaced with a hybrid like 2b, a simple synthesizer is used here to simplify the circuit.

FIG. 7 shows the directivity characteristics of the output obtained by this embodiment, and FIG. 8 is a diagram showing an example in which the present high-frequency signal processing circuit is attached to a parabolic antenna, which is the first application example of the present invention. The radiation pattern 8 in FIG. 7 corresponds to the radiation pattern from the aperture 6 of the parabolic antenna in FIG. The beam width is narrow. Therefore, when temporarily setting up a satellite communication line using a portable or mobile antenna, it is necessary to use a tracking antenna device like the one above for initial acquisition of the satellite. It is something that needs to be done.

Here, in order to configure the above-mentioned tracking antenna device, in addition to the above-mentioned high-frequency signal processing circuit using monopulse tracking, a low-noise amplifier (LNA), which is called a normal tracking receiving device in satellite communication, and a frequency converter (D/ C) and an amplitude and phase detector (DEM) are required.

In the application example shown in FIG. 8, the sub-reflecting mirror 7 and the main reflecting mirror 6 need to be set within a required precision. If this accuracy does not satisfy the required performance, the beam axis deviation between the radiation pattern from the main reflector tIL6 and the radiation pattern from the sub-reflector 5 will become large, and no matter how much monopulse tracking is used, the beam axis deviation will continue. Therefore, it is clear that it is not useful for initial acquisition.

FIG. 9 shows another application example of the present invention in which a portable antenna is used for initial acquisition of a satellite, and this is an example in which the invention is applied to a foldable antenna. That is, the monopulse signal processing circuit 5 is attached to the back of the antenna main reflector 6, and the monopulse signal processing circuit 5 is previously directed toward the satellite before the antenna is deployed.

After the initial acquisition of the satellite is completed, the antenna is deployed and a satellite communication line is set up. It should be noted that the monopulse signal processing circuit 5 may be installed at a position indicating the mirror axis direction of the antenna instead of at the back of the antenna, and the same effect as described above can be obtained.

Furthermore, although the above embodiment has shown a tracking antenna device in which a monopulse signal processing circuit is used auxiliarily, the high frequency signal processing circuit using the monopulse tracking method described above is a third application of the present invention shown in FIG. As shown in the example,
It can also be used as the −order radiator of a Cassegrain antenna (Gregorian antenna), or the parabolic primary radiator itself.
This makes it possible to obtain an antenna device with a tracking function. In this case, it has the advantage of being significantly smaller and lighter than a high-frequency signal processing circuit using a monopulse tracking method using a conventional three-dimensional circuit (waveguide circuit).

Note that the sum signal terminal of the embodiment of the present invention can be operated not only as a tracking reference signal terminal but also as a communication signal terminal.

〔Effect of the invention〕

As described above, according to the present invention, the high-frequency signal processing circuit using the monopulse tracking method is made into a planar antenna using a microstrip line, etc., so the device can be made smaller and lighter, and furthermore, the device can be made cheaper. , there is also the effect of obtaining a packaged product.

[Brief explanation of the drawing]

FIG. 1 is a front view of a high-frequency signal processing circuit of a target tracking device according to an embodiment of the present invention, FIG. 2 is a rear view of the same, FIG. 3 is a sectional view of the same, and FIG. 4 is a principle of the present invention and a conventional example. Explanatory drawings: FIG. 5 is a diagram showing a conventional four-horn example high-frequency signal processing circuit; FIG. 6 is a diagram showing the principle and external appearance of the present invention; FIG.
The figure is a diagram showing the directivity characteristics of each output for detailed explanation of the present invention, Figure 8 is a diagram showing a first example of application to a parabolic antenna of the present invention, and Figure 9 is a diagram showing a first application example of the present invention to a folding antenna. FIG. 10 is a diagram showing a third application example in which the present invention is applied to a primary radiator of a Cassegrain antenna. la, lb, lc, ld are four batch antennas, 2a
is the first hybrid, 2b is the second hybrid, 3
a, 3b, and 3c are output terminals of the sum signal Σ, difference signal ΔAz, and difference signal ΔEl, respectively, and 4a. 4b and 4c are coaxial outputs, 5 is a high frequency signal processing circuit, 6 is a main reflecting mirror, and 7 is a sub reflecting mirror. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] (1) at least four patch antennas configured with microstrip lines, at least three hybrid circuits, a connection circuit connecting the four patch antennas and the at least three hybrid circuits, and the hybrid A high-frequency signal processing circuit for a target tracking device using a monopulse tracking method, comprising at least three microstrip-to-coaxial converters that convert the output of the circuit into a coaxial output.