JP2551301B2 - Phased array antenna monitoring equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art FIG. 4 shows a conventional phased array of this type.
It is a block diagram which shows an example of the monitoring apparatus of an antenna . Phased array antenna system of the monitoring device of the phased array antenna comprises a power divider 1 distributes a transmission signal to a plurality of crossroads, a plurality of phase shifters 2 connected to the respective branch of the power distributor 1, these It is composed of a plurality of antenna elements 3 which respectively radiate the output of the phase shifter 2 as radio waves. 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, a phase shifter 16 for shifting the phase of the signal 208 by 90 degrees, a phase shift amount designation signal generator 6 for controlling the phase shift amount of the phase shifter 2 at a desired time, A receiving element 4 arranged in front of the plurality of antenna elements 3 for receiving radio waves radiated by these antenna elements 3.
A distributor 80 for distributing the reception output of the reception element 4 into signals 109 and 209; a mixer 9 for receiving the signals 108 and 109; an output for the phase shifter 16 and an output for the signal 209. Mixer 90 and mixers 9 and 90
It is composed of detectors 5 and 50 which respectively receive the outputs of the above.

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 by the signal distributor 8 to the signals 108 and 208.
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 209, and the signal 109 is added to the mixer 9 and the signal 209 is added to the 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 the level of the input signal and output it.

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 (where n is an integer), the phase shift amount designation signal generator 6 monotonically increases or decreases n times or more, and the detectors 5 and 50 detect the AC level.

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 above-mentioned conventional phased array antenna monitoring device, 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 take time. Also, in the digitized phase shifter which is mainly used these days, when the phase shifter fails, the output level of the phase shifter usually fluctuates according to the phase shift amount. 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 monitoring device of a phased array antenna which can realize reliable phased array antenna monitoring device at a low.

[0010]

SUMMARY OF THE INVENTION A phased array antenna monitoring apparatus according to the present invention transmits a transmission signal from a first signal to a (n + 1) th signal.
(N is a positive integer) and branching means for branching the crossroads of connected respectively from the first to the (n + 1) th branch tare Ri phase shift finger
When the constant signal is received, the phase shift specified by the phase shift amount designation signal
A phase shifter for shifting the phase of the transmission signal propagating in the inside by an amount and a first to n + 1th phase shifter and a first to nth phase shifter respectively receiving and radiating as a radio wave. A receiving element for receiving the radio wave, and a receiving element
A combiner for combining the output and the output of the (n + 1) th phase shifter
And a detector for detecting and outputting the output level of the synthesizer
And a first phase shift amount over a first time period starting at the desired time.
The phase shift amount designation signal for designating
To the phase shifter of the first to nth air
Of the signal emitted from the line element and output by the receiving element
The first to nth antenna elements are to be monitored.
Radio waves emitted from antenna elements other than the antenna elements
Phase when the components to be synthesized are input to the synthesizer
In contrast, the output of the (n + 1) th phase shifter is input to the combiner.
So that the phase at the time of
The phase shift amount designation signal that designates the phase shift amount of the phaser is output and the second
Connected to the antenna element to be monitored over time
The phase shifters other than the existing phase shifter at the first time.
The amount of phase shift that changes by 90 degrees relative to the amount of phase shift
It is equipped with a phase shift amount designation signal generator that outputs a designation signal.
Is made.

[0011]

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

[0012] Figure 1 is a block diagram showing an embodiment of <br/> monitor phased array antenna of the present invention.

Monitoring of this phased array antennaapparatus
Is the relative level of the received wave from the monitored antenna element
Relatively small relative to the relative level of the received wave from the entire line element
Even when there is no signal received from the antenna element to be monitored
Relative levelLeEquivalently to increase the measurement resolution.
Wear.

Monitoring of the phased array antenna of this embodiment
As shown in FIG. 1, the device comprises the same power distributor 1, a plurality of phase shifters 2, an antenna element 3 and a receiving element 4 already shown in FIG.

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 passed through the phase shifter 10 and the signal received by the receiving element 4, and a combination The detector 5B that detects and outputs the output level of the phase shifter 11, the feeding 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 that the receiving element 4 receives the radio waves radiated from the plurality of antenna elements 3 shown in FIG. 1 at the first and second times . 3 is an explanatory diagram showing a relationship between a vector of a signal output to the combiner 11 and a vector of a signal output from the phase shifter 10 and input to the combiner 11. FIG.

In the vector of the reception wave output from the reception element 4, the signals of the reception waves from the other antenna elements 3 excluding the antenna element to be monitored (any one of the plurality of antenna elements 3) are synthesized. 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 is a vector diagram showing the relationship between the vectors a, b, α, x, γ and the angle θ at the first time described above.

Next, by the signal output from the phase shift amount designation signal generator 6B, 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. It is assumed that 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 elements 3 other than the monitored antenna element output from the receiving element 4 and the vector component of the received wave from the monitored antenna element.

FIG. 3 shows the vector a, at the second time
It is a vector diagram which shows the relationship with b, (beta), x, (delta), and the angle (theta). The above γ and δ are respectively expressed by the following equation (1)
And (2).

[0023]

[0024]

From the equations (1) and (2), the following equation (3) is derived.

[0026]

Of the detector 5B at the first and second times
From the output levels γ and δ, and the equation (3), the received wave relative amplitude a of the antenna element to be monitored can be known, and further the received wave relative phase can be obtained from the equations (1) and γ, or the equation (2) and δ. The θ 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 relative amplitude a and the relative phase θ of the received wave from the monitored antenna element.

[0029] Thus, according to the monitoring device of the phased array antenna of the present invention, by a detector 5B, first
Measure output level γ of time and output level δ of second time
By doing so , the relative amplitude a of the antenna element to be monitored can be known from the relationship of the expression (3), and the relative phase θ can be known from the relationship between the relative amplitude a and the expression (1) or the expression (2). By recording or storing the relative amplitude a and the relative phase θ in, 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.
Needless to say, 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 taken out 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. Ma
Moreover, in the embodiment shown in FIG. 1, the phase shifters 2 and 1
And a power distributor 1 as a means for branching a transmission signal for 0.
Although the coupling element 7B is used,
The coupling element 7B and the coupling element 7B are combined to form a branching unit.
By means of a plurality of phase shifters 2 and 10 respectively.
It is clear that the desired power can be distributed
It

[0032]

As described above, in the phased array antenna monitoring apparatus of the present invention, since the RF circuit and the detector of the monitoring system are one channel, it is possible to obtain inexpensive and highly reliable measurement results. . 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 amount of phase shift of the phase shifter. Therefore, in the conventional phased array antenna monitoring device , when the output level of the phase shifter changes depending on the amount of phase shift, the output of the detector is distorted from the sine wave and the measured phase and amplitude errors are large. Also has the effect of high measurement accuracy of the phase and amplitude.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a phased array antenna monitoring apparatus of the present invention.

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 of FIG.

FIG. 4 is a block diagram showing an example of a conventional phased array antenna monitoring device of this type.

[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)

(57) [Claims] 1. 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 + 1) th phase shifts, which are respectively connected to the +1 branch lines and shift the phase of the transmission signal propagating inside by the phase shift amount designated by the phase shift amount designation signal when the phase shift amount designation signal is received. And a receiving element for receiving the radio wave with respect to a phased array antenna, which receives the outputs of the first to nth phase shifters and emits the radio wave as a radio wave. a combiner for combining the output of the receiving element and the output of the phase shifter of the first n + 1, a detector that outputs detecting the output level of the synthesizer, the first
To radiate the transmission signal from the antenna element
Form the essential original phased array antenna radiation beam
The time required to control the first to nth phase shifters.
Any first time and second time that do not overlap other than
During the interval, the phase shift amount designating signal designating the phase shift amount at the first time is applied to the first to nth phase shifters and is radiated from the first to nth antenna elements. In the signal output from the receiving element, a component that is combined by radio waves emitted from antenna elements other than the antenna element to be monitored among the first to nth antenna elements is input to the combiner. Phase shift amount that specifies the phase shift amount of the (n + 1) th phase shifter so that the phase when the output of the (n + 1) th phase shifter is input to the combiner is opposite to the phase when at a second time and outputs a specified signal
The phase shift amount designation signal causing the transfer relatively 90 Do推 the phase of the phase shifter other than the phase shifter which is connected to the antenna element according to the monitored relative phase shift in the first time Te A phased array antenna monitoring device comprising a phase shift amount designation signal generator for outputting.