JPS58103206A - Array antenna device - Google Patents

Abstract

PURPOSE:To prevent both deterioration of gain and null shift of a differential pattern, by using a hybrid coupler to a directional coupler that has a coupling degree to compensate a power loss due to a difference of the delay line lengths. CONSTITUTION:The difference of power loss between the delay line (3-2)(3-3) of a group B and the delay line (3-1) of a group A, i.e. the power loss of the 2nd line (3-3) is set at DELTALdB. In such case, the coupling degree CAdB between the terminal SIGMA of a directional coupler 6 and the line (3-3) is set so as to satisfy the equation 1. Thus the electric power to be distributed to the group B through the terminal SIGMA is larger than the electric power to be distributed to the group A by an amount of DELTALdB. Therefore the electric wave supplied through the terminal SIGMA is divided into two parts. Then the electric power obtained when the divided electric waves reach a coupler (2-1) for radiator is equal to the electric power obtained when the divided electric waves reach a coupler (2-3) for radiator. Therefore the levels of the amplitude distributions coincide with each other at the boundary between the groups A and B. This can prevent the occurrence of a null shift of a differential pattern as well as the deterioration of gain.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a frequency scanning array antenna device having a monopulse angle measurement function.

A conventional device of this type is shown in FIG. In the figure, (1-1) to (1-4) are radiators, (2-1
) to (2-4) are radiator couplers, (3-1) (3-2
) is the radiator (1-1) (1-2) or (1-3) (1-
4) The first delay line gives a phase difference between the signals, (4)
-1) (4-2) is a non-reflection terminator, (7-1) (7-2
) are respectively radiators (1-1) (1-2) or (1-3
)(1-4), first delay line (3-1) or (3-2
) and a non-reflection terminator (4-1) or (4-2), (3-3) is continuous with the first delay line (3-2) of the antenna circuit (7-2). A delay line of I82 is provided to provide a phase difference between the signals of both antenna circuits (7-1) and (7-2), and (5) is a no.1 hybrid coupler (
3dB coupler), Σ, and Δ are its input and output terminals. Here, the circuit including the radiators (1-1) and (1-2) will be referred to as group A, and the circuit including the radiators (1-3 and 1-4) will be referred to as group B.

Next, the principle of a frequency scanning antenna will be explained. For simplicity, we will omit the radiator coupler and consider the circuit shown in Figure 2.

The length of the delay line (3-1) from the radiator (1-1) to the radiator (1-2) is S, the wavelength in the line is λg, the spatial wavelength is λ, and the radiator (1-1) and ( 1-2) and the beam direction angle is θ, the following relationship exists between them.

or can be obtained. From equation (2), the frequency, and therefore χ.

By changing χg, the beam directivity angle θ can be changed. This is the principle of a frequency scanning array antenna.

Now, returning to FIG. 1, the operation will be explained.

The radio waves input from the Σ terminal of the hybrid coupler (5) are equally divided into two, and one radio wave passes through the delay line (3-1) and reaches the radiator coupler (2-1).

Here, radio waves branched according to the coupling degree of the radiator coupler (2-1) are radiated from the radiator (1-1). The remaining radio waves reach the radiator coupler (2-2), are branched according to the degree of coupling, and are radiated from the radiator <1-2). The remaining radio waves are absorbed by the non-reflection terminator (4-1).

On the other hand, the radio waves distributed to the delay line (3-3) are radiated from the radiators (1-3) (1-4) in the same manner as above, and the rest are sent to the non-reflection terminator (4-2) G. This is absorbed.

Here, each radiator (1-1), (1-2), (1-3).

(1-4) is d, and the hybrid coupler (5
) to radiator coupler (2-1), (2-2),
(2-3).

Let the delay line length up to (2-4) be ll+12, respectively.
As e J'1ej4, lx-11= 6 12= 14-1s= S...
If you choose (3),
As already explained, the radio waves input from the Σ terminal of the hybrid coupler (5) are radiated from the radiators (1-1) to (1-4) at the beam direction angle θ given by equation (2). Ru.

The above explained the case of sending, but in the case of receiving,
Following the opposite route to the above, the hybrid coupler (5) combines the sum signal obtained by in-phase combining all the radio waves of the radiators (1-1) to (1-4) with the sum signal of the radiators (1-1) and ( 1-2
) and a difference signal obtained by taking the difference between the combined waves of radiators (1-3) and (1-4), the sum signal is taken out from the Σ terminal, and the difference signal is taken out from the Δ terminal. be done.

Since the conventional frequency scanning array antenna device having a monopulse angle measurement function is configured as described above, the delay line of group B <3-2) (3-3) is replaced by the delay line of group A (3-3).
Compared to 1), the line length of the second delay line (3-3) is longer by 2S, and there is a difference in power loss between the two lines corresponding to the line length of 25, and as a result, at the boundary between Group A and Group B, As shown in FIG. 3, the power loss difference has a step difference ΔL in the amplitude distribution, resulting in a decrease in gain and a null shift in the difference pattern.

This invention was made in order to eliminate the drawbacks of the conventional ones as described above, and in a frequency scanning array antenna and device having a monopulse angle measurement function, a hybrid coupler is used to compensate for power loss due to difference in delay line length. It is an object of the present invention to provide an array antenna device that can prevent a decrease in gain and a null shift of a difference pattern by using a directional coupler having a degree of coupling as follows.

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

FIG. 4 shows a frequency scanning array antenna device having a mono 4T angle measurement function according to an embodiment of the present invention. In the figures, the same symbols as in Fig. 1 indicate the same parts as in the same figure, and (
6) is a directional coupler having a degree of coupling that compensates for power loss in the second delay line (3-3) of group B.

Next, the effects will be explained.

Power loss of delay lines (3-2) (3-3) of group B and A
When the difference from the power loss in the group delay line (3-1), that is, the power loss in the second line (3-3), is ΔLdB, the delay line ( The power distributed from the triplets to group B is ΔL lower than the power distributed to group A.
dB more is distributed. Therefore, the radio waves input from the Σ terminal are divided into two parts, which become equal, and as shown in Figure 5, the level of the amplitude distribution matches at the boundary between groups A and B, resulting in a decrease in gain and a null shift in the difference pattern. will not occur.

Here, as a directional coupler (6), the phase difference after distribution is 90
When using a 90° phase shifter, correction is performed using a 90° phase shifter. For example, if the phase of the radio wave input from the Σ terminal and distributed to group A is delayed by 90 degrees than that distributed to group B, the phase is changed to the delay line (3-1) of group A by 90 degrees. Either insert a phase shifter to advance the
2) A phase shifter that delays the phase by 90 degrees may be inserted in (3-3). However, in this case, it is necessary to determine the degree of coupling of the directional coupler (6) in consideration of power loss in the inserted phase shifter.

In the above embodiment, the case of series power supply has been described, but the present invention can also be applied to the case of parallel power supply as shown in FIG. 6, and the same effects as in the above embodiment can be obtained. Further, in the above embodiment, the case where the number of radiators is four has been described, but the number of radiators may be greater than four. Further, in the above embodiment, the amplitude distribution is a uniform distribution, but the amplitude distribution may of course be a Taber-like distribution.

As described above, according to the present invention, in a frequency scanning array antenna device having a monopulse angle measurement function, as a combiner that distributes a signal to an antenna circuit or synthesizes a sum signal and a difference signal from signals from the antenna circuit, Since a directional coupler having a degree of coupling that compensates for power loss due to a difference in delay line length between antenna circuits is used, it is possible to prevent a decrease in gain and a null shift of a difference pattern.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a conventional frequency scanning array antenna device having a monopulse angle measurement function, Fig. 9J2 is a diagram for explaining the principle of a frequency scanning antenna, Fig. 3 is a diagram showing the amplitude distribution in the above device, FIG. 4 is a configuration diagram of a frequency scanning array antenna device having a monopulse angle measurement function according to one embodiment of the present invention, FIG. 5 is a diagram showing the amplitude distribution of the above device, and FIG. 6 is a diagram according to another embodiment of the present invention. FIG. 2 is a configuration diagram of an array antenna device. (1-1) to (1-4)...Radiator (antenna), (
3-1) (3-2)...first delay line, (3-3)
... second delay line, (6) ... directional coupler, (
7-1) (7-2)...Antenna circuit. In the drawings, the same reference numerals indicate the same or equivalent parts. Agent Shin Kuzuno - Figure 1 Figure 2 Figure 3 Figure 5 Figure 4 ΔΣ

Claims (1)

[Claims] C1) A frequency scanning array antenna device having a monopulse angle measurement function, comprising a plurality of antenna circuits each including a pair of antennas and a first delay line that provides a phase difference between the signals of both antennas, and the adjacent antennas. A second delay line that provides a phase difference between the signals of the circuit, and a degree of coupling that compensates for power loss in the second delay line, and distributes the transmission signal to each of the antenna circuits, or distributes the transmission signal to each of the antenna circuits. An array antenna device comprising a directional coupler that combines a sum signal and a difference signal from received signals from a circuit.