JPH05322947A - Phased array antenna monitoring method - Google Patents

Abstract

PURPOSE:To accurately and individually detect the level of an electric wave which is radiated from each antenna element of a phased array antenna. CONSTITUTION:A phase shifter 10 is provided in addition to n phase shifters which are connected to each antenna element 3. A coupling element 7B which outputs one part of transmission signal which is supplied to the phase shifter 2 and a synthesizer 11 which synthesizes the output of a reception element 4 for receiving electric wave which is radiated from the antenna element 3 and that of the phase shifter 10 is provided. Phases which are different by 90 degrees are given to the phase shifter 2 and the phase shifter 10 which are connected to antenna elements other than those to be inspected at a first time starting from a desired time and a second time which is different from the first time by a generator 6B of specification signal of the amount of shift, the level of the reception wave is detected and output by a detector 5B which is connected to the output side of the synthesizer 11 at the first and the second times, and then the relative amplitude and the relative phase which are output from the antenna element to be inspected are obtained from these two levels.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for monitoring a phased array antenna, and more particularly to a microwave landing gear [MLS].
(Microwave landing system
m)] and the like, the present invention relates to a phased array antenna monitoring method for monitoring the phase and level of radio waves radiated from each antenna element forming an array of phased array antennas.

[0002]

2. Description of the Related Art FIG. 4 is a block diagram showing an example of a phased array antenna monitoring apparatus to which a conventional monitoring method of this type is applied. The phased array antenna system of this phased array antenna monitoring system includes a power distributor 1 for distributing a transmission signal to a plurality of branches, a plurality of phase shifters 2 connected to the respective branches of the power distributor 1, and a phase shifter for these phases. It is composed of a plurality of antenna elements 3 each of which outputs the output of the container 2 as a radio wave. Further, the level and phase monitoring system of the transmission signal radiated from each antenna element 3 includes a coupling element 7 for extracting a part of the transmission signal and a portion of the transmission signal for extraction by the coupling element 7 into signals 108 and 208. A signal distributor 8 for distributing and a phase shifter 16 for shifting the phase of the signal 208 by 90 degrees.
And a phase shift amount designation signal generator 6 for controlling the amount of phase shift of the phase shifter 2 at a desired time, and a plurality of antenna elements 3 arranged in front of the antenna elements 3 to receive radio waves radiated by these antenna elements 3. Receiving element 4 and the received output of the receiving element 4 to signals 109 and 2
09, a divider 80 for dividing the signal into the mixer 09, a mixer 9 having the signals 108 and 109 as inputs, an output of the phase shifter 16 and a signal 2
And the mixer 90 that receives the output of 09 and the mixer 9
And detectors 5 and 50 having outputs of 90 as inputs, respectively.

When monitoring the level and phase of the radio wave output from the antenna element 3, the signal output from the coupling element 7 is distributed to the signals 108 and 208 by the signal distributor 8.
The signal 108 is added as one input of the mixer 9, and the signal 208 is phase-shifted by 90 degrees by the phase shifter 16 and then added as one input of the mixer 90.

On the other hand, the radio wave radiated from the plurality of antenna elements 3 is received by the receiving element 4, and its output is signal distributor 80.
Signal 109 and signal 209, and signal 109 is applied to mixer 9 and signal 209 is applied to mixer 90 as another input.

The mixer 9 synthesizes the above-mentioned input signals and outputs it as a signal 110 to the detector 5, and the mixer 90
Outputs the above-mentioned input signals to the detector 50 as a signal 210. The detectors 5 and 50 detect and output the levels of the input signals, respectively.

In this conventional phased array antenna monitoring device, when monitoring the level and phase of the transmission signal radiated from one antenna element (one of the antenna elements 3), the other antenna element 3 The phase shift amount of the connected phase shifter 2 is fixed during that period, and the phase shift amount of the phase shifter 2 connected to the antenna element 3 to be monitored is set to (360
Degree) / n (n is an integer), the phase shift amount designation signal generator 6 monotonically increases or decreases n times or more, and the AC levels are detected by the detectors 5 and 50.

At this time, the waveforms detected by the one detector 5 and the other detector 50 are both sine waves, and their phases differ from each other by 90 degrees. Therefore, the RF phase of the transmission signal of one antenna element 3 being monitored at the same time can be known from the phase of the detected waveform at a certain time, and the level of the transmission signal can be known from the AC level. In this way, the level and phase of the transmission signal of each antenna element 3 are obtained.

[0008]

In the conventional phased array antenna monitoring apparatus described above, since a sine wave is obtained as the detection waveform, the phase shift amount of the phase shifter must be rotated by 360 degrees or more, and the processing is performed. take time. Also, in the digitized phase shifter that is mainly used these days, when the phase shifter fails, the output level of the phase shifter usually changes according to the phase shift amount, so the detected waveform is Has a distortion component. Therefore, the level and phase of the transmission signal obtained by this monitoring method lose accuracy. Also, the monitoring system is R
The F circuit (signal distributor, mixer, and line connecting these) and the detector each require two channels, which is expensive and low in reliability.

An object of the present invention is to provide a method for monitoring a phased array antenna which can realize an inexpensive and highly reliable phased array antenna monitoring device.

[0010]

According to the method of monitoring a phased array antenna of the present invention, a transmission signal is transmitted from the first to (n + 1) th transmission signals.
(N is a positive integer) branching means, first to n + 1th phase shifters respectively connected to the first to n + 1th branches, and the first to nth phase shifters To the phased array antenna including the first to nth antenna elements that respectively receive the output of the vessel and emit as radio waves,
A phase shift amount designation signal generator for giving a signal designating a phase shift amount in the phase shifter to each of the phase shifters, a receiving element for receiving the radio wave, an output of the receiving element and the n + th signal.
A combination notation for combining the output of the phase shifter of No. 1 and a detector for detecting and outputting the output level of the combiner are provided, and a first time starting at a desired time and a time other than the first time And a second time period starting at time, the phase shift amount designation signal generator is configured so that the phase shifter not connected to any one of the (n + 1) th phase shifter and the antenna element to be monitored. To the first and second times, the signals for designating the phase shift amounts different from each other by 90 degrees are given to the first and second times, respectively.
And, at the second time, the radio wave is received by the receiving element, and an output for obtaining the level and phase of the antenna element to be monitored is output as a detection level from the detector.

[0011]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of a phased array antenna monitoring apparatus to which the method for monitoring a phased array antenna of the present invention is applied.

In this phased array antenna monitoring method, even when the received wave relative level from the monitored antenna element is relatively small with respect to the received wave relative level from the entire antenna element, the measured antenna element from the monitored antenna element to be measured. It is possible to equivalently increase the received wave relative level and improve the measurement resolution.

As shown in FIG. 1, the method of monitoring a phased array antenna of the present embodiment includes the same power divider 1, a plurality of phase shifters 2, an antenna element 3, and a receiving element 4 as already shown in FIG. Is equipped with.

In the embodiment of FIG. 1, in addition to these,
Coupling element 7 for extracting a part of the transmission signal to antenna element 3.
B, a phase shifter 10 that controls the phase of the RF signal extracted by the coupling element 7B, a combiner 11 that combines the signal that has passed through the phase shifter 10 and the signal received by the receiving element 4, and combining The detector 5B that detects and outputs the level of the output of the phase shifter 11, the feed line 12 between the coupling element 7B and the phase shifter 10, and the 90-degree phase shift applied to the phase shifter 2 and the phase shifter 10. Phase shift amount designation signal generator 6B controlled at the same timing
It has and.

2 and 3 show the vector of signals received by the receiving element 4 among the radio waves radiated from the plurality of antenna elements 3 shown in FIG. 5 is an explanatory diagram showing a relationship with a vector of a signal output from the phaser 10 and input to the combiner 11. FIG.

In the vector of the received wave output from the receiving element 4, the signals of the received waves from the other antenna elements 3 except the monitored antenna element (any one of the plurality of antenna elements 3) are combined. Let b be the amplitude of the vector, and normalize with b (the value of b is 1), and let a be the amplitude of the component of the received wave output from the antenna element to be monitored and received by the receiving element 4. , The relative phase of these two received waves is θ (degree) +
The degree is 90 (degrees), and the level input to the combiner 11 at this time is α. The phase shifter 10 is output from the coupling element 7B.
Let x be the amplitude of the RF signal sent to the combiner 11 via.

Further, the phase of the RF signal is controlled by the phase shifter 10, the power feeding path 12, the phase shifter 2 or a combination thereof so that the phase is opposite to the normalized amplitude b.

Further, as shown in FIG. 2, b (=
The level of the signal output from the coupling element 7B to the power feeding path 12 is preset so that the absolute value of x becomes slightly smaller than that in 1). In this case, the level detected and output by the detector 5B is γ.

FIG. 2 shows the vectors a, b, and
It is a vector diagram which shows the relationship with (alpha), x, (gamma), and the angle (theta).

Next, the phase shift between the phase shifter 2 and the phase shifter 10 connected to the antenna elements other than the above-mentioned monitored antenna elements is performed by the signal output from the phase shift amount designation signal generator 6B. The amount is shifted by 90 degrees from the state shown in FIG. At this time, the level detected and output by the detector 5B is δ
Let β be the composite vector of the vector component of the received wave generated by the antenna element 3 other than the monitored antenna element output from the receiver element 4 and the vector component of the received wave from the monitored antenna element.

FIG. 3 shows the vectors a, b, β, and
It is a vector diagram which shows the relationship with x, (delta), and the angle (theta).
The above γ and δ are expressed by the following equations (1) and (2), respectively.
It is represented by.

[0023]

[0024]

The following equation (3) is derived from the equations (1) and (2).

[0026]

Therefore, γ and δ are output by the detector 5B, and a, which is the relative amplitude of the received wave of the antenna element to be monitored, is known from the equation (3), and further, the equation (1) and γ or the equation (2) ) And δ, the θ of the received wave relative phase is known.

By selecting x to be 0 <x <1, the measurement level γ at the detector 5B becomes smaller than α,
Similarly, since δ is smaller than β, it is possible to relatively improve the accuracy of the received wave relative amplitude a and the relative phase θ from the monitored antenna element.

Thus, according to the phased array antenna monitoring method of the present invention, γ and δ are detected by the detector 5B.
, The relative amplitude a of the antenna element to be monitored can be known from the relation of the expression (3), and the relative phase θ can be obtained from the relation of the relative amplitude a and the expression (1) or (2).
Therefore, by recording or storing the relative amplitude a and the relative phase θ in advance, it is possible to monitor how the relative amplitude and phase of each antenna element changes with the passage of time. .

In this case, when the phase shifter other than the monitored antenna element shifts the phase by 90 degrees, the RF signal obtained from the coupling element 7B is also synchronized with the phase shift amount designation signal generator 6B.
It goes without saying that it is necessary to shift the phase by 90 degrees.

In the embodiment shown in FIG. 1, the radiation signal from the antenna element is received by the receiving element. However, the signal extracted from the coupling element before the signal is emitted from the antenna element. Needless to say, it is possible to monitor the amplitude and phase of the signal supplied to the antenna element by using.

[0032]

As described above, according to the method for monitoring a phased array antenna of the present invention, since the RF circuit and the detector of the monitoring system have one channel, it is possible to obtain a low-cost and highly reliable measurement result. Further, in the present invention, since the phase and amplitude of the radio wave radiated by the monitored antenna element are obtained for each phase shift amount of the phase shifter, the output level of the phase shifter connected to the monitored antenna element is The obtained phase and amplitude are accurate even if they change according to the phase shift amount of the phase shifter. Therefore, in the conventional phased array antenna monitoring method, when the output level of the phase shifter changes depending on the amount of phase shift, the output of the detector is distorted from a sine wave, and the measured phase and amplitude errors are large. Also has the effect that the measurement accuracy of the phase and amplitude is high.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a phased array antenna monitoring apparatus to which a method for monitoring a phased array antenna of the present invention is applied.

FIG. 2 is a vector diagram illustrating a received wave input to the detector shown in FIG.

FIG. 3 is a vector diagram for explaining a received wave input to the detector shown in FIG. 1 at a time different from that in FIG.

FIG. 4 is a block diagram showing an example of a phased array antenna monitoring apparatus to which a conventional monitoring method of this type is applied.

[Explanation of symbols]

 1 power divider 2 phase shifter 3 antenna element 4 receiving element 5 detector 5B detector 6 phase shift amount designation signal generator 6B phase shift amount designation signal generator 7 coupling element 7B coupling element 10 phase shifter 11 combiner

Claims (1)

[Claims] 1. A branching means for branching a transmission signal into a branch from a first to an n + 1th branch (n is a positive integer), and the first to the nth branch.
The first to n + 1th phase shifters respectively connected to the +1 branch path, and the first to nth antenna elements which receive the outputs of the first to nth phase shifters and radiate them as radio waves, respectively. With respect to the phased array antenna provided, a phase shift amount designation signal generator that gives a signal designating a phase shift amount in the phase shifter to each of the phase shifters, a receiving element that receives the radio wave, and a receiving element of the receiving element. A synthesis record for synthesizing an output and the output of the (n + 1) th phase shifter, and a detector for detecting and outputting the output level of the synthesizer are provided, and a first time starting at a desired time and the first time Second starting at a time other than
And the phase shift amount designation signal generator
The phase shifter not connected to any one of the +1 phase shifter and the antenna element to be monitored has a phase shift amount different from each other by 90 degrees in the first and second times. Detecting an output from the detector for giving the specified signals respectively, receiving the radio waves at the receiving element at the first and second times, and obtaining the level and phase of the antenna element to be monitored. A phased array antenna monitoring method characterized by outputting as a level.