JP2015076703A - Antenna device and antenna exciting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the influence of an exciting amplitude phase error generated in each phase shift state of an element antenna constituting a fuse array antenna.SOLUTION: By adding a phase offset amount φ to an excitation phase βset by an excitation phase setting part 7, a phase offset part 11 which repeatedly sets a new excitation phase θand a phase shifter control signal output part 11 which controls a phase shift state of a phase shifter 3-m in accordance with the new excitation phase θare provided. In a time average processing part 12, digital reception data outputted from a receiver 5 is accumulated each time when the phase shift state is controlled by the phase shifter control signal output part 11, and time average of the digital reception data is calculated.

Description

  The present invention relates to an antenna device and an antenna excitation method for reducing the influence of an excitation amplitude phase error generated in each phase shift state of an element antenna constituting a phased array antenna.

A communication system using a phased array antenna includes a plurality of element antennas, a phased array antenna including a plurality of phase shifters connected to the element antennas, and a phase shifter control device that controls the plurality of phase shifters. Is done.
When a digital phase shifter is used as the phase shifter, the phase shift state of each phase shifter can be easily controlled by the phase shifter control device, so that the antenna radiation pattern can be controlled electronically. It is widely used as an antenna for satellite communication systems and radar systems.

In general, a digital phase shifter includes a plurality of semiconductor elements such as diodes, and a plurality of phase shift states are realized by appropriately combining operation states / non-operation states of the plurality of semiconductor elements.
However, since the semiconductor element has different operating characteristics for each individual, the passing characteristics of the digital phase shifter are different for each phase shift state.
The antenna radiation pattern is determined by the variation in pass characteristics for each phase shift state (hereinafter referred to as “pass phase error”) and the variation in insertion loss (pass amplitude) (hereinafter referred to as “pass amplitude error”). It may be different from the characteristic and may cause characteristic deterioration.

As a countermeasure against characteristic deterioration, a method of determining an antenna excitation phase that reduces deterioration of antenna gain due to a passing characteristic for each phase shift state of a digital phase shifter has been proposed (for example, Patent Document 1 and Non-Patent Document 1). reference).
That is, in Patent Document 1, it is determined by quantizing the phase shift value in consideration of the passing amplitude error while offsetting the phase shift value of an ideal analog value that realizes a desired characteristic by a minute amount. A method is disclosed in which an antenna gain reduction amount in a phase shift state is calculated, and a phase shift state that minimizes the antenna gain reduction amount is determined as an antenna excitation phase.
Further, Non-Patent Document 1 describes a desired phased array by improving antenna gain degradation, null depth, and the like by simultaneously considering a passing amplitude error and a passing phase shift error for each phase shift state of the phase shifter. A method for calculating an antenna excitation phase that realizes an antenna radiation pattern with high accuracy is disclosed.

However, in the phased array antenna, it is not easy to freely control the excitation amplitude, and in Patent Document 1 and Non-Patent Document 1, only correction (setting) of the excitation phase is considered.
On the other hand, in the phased array antenna, as a technique for realizing amplitude phase control, a time modulation array antenna using the concept of time weight is disclosed in Non-Patent Documents 2 and 3 below.
This is because the same effect (radiation characteristics) as a state in which a predetermined amplitude distribution is given equivalently by time averaging (time integration) of signals received or transmitted at a plurality of excitation phases. To get.

JP 2011-217299 A

Nakamoto et al., Study on high-accuracy beamforming method considering element electric field error in all phase-shifted state of phased array antenna, IEICE Technical Report AP2012-169, pp.31-36, 2013. W. Kummer et al., Ultra-Low Sidelobes from Time-Modulated Arrays, IEEE Transactions on Antennas and Propagation, vol.11, iss.6, pp.633-639, 1963. Nakanishi et al., Experimental verification of switching switching algorithm for excitation suppression of unwanted harmonics in time-modulated array antenna, IEICE General Conference, B-1-213, 2013.

Since the conventional antenna device is configured as described above, in the case of Patent Document 1 and Non-Patent Document 1, only the correction of the excitation phase error is considered due to the restriction of using the phase shifter, and the excitation amplitude error is reduced. It cannot be corrected. That is, a search is made for a combination of excitation phases in which the influence of the pass amplitude error and the pass phase shift error is small, and there is a problem that the excitation error itself cannot be reduced.
On the other hand, in the case of Non-Patent Documents 2 and 3, although the performance of the phased array antenna can be improved, no countermeasure is disclosed for the excitation amplitude or excitation phase error, and the excitation amplitude or excitation phase error should be reduced. There was a problem that could not be done.

  The present invention has been made to solve the above-described problems, and an antenna device and an antenna excitation capable of reducing the influence of an excitation amplitude phase error generated in each phase shift state of an element antenna constituting a phased array antenna. The purpose is to obtain a method.

  An antenna device according to the present invention includes a plurality of phase shifters connected to element antennas constituting a phased array antenna, a combiner that combines output signals of the plurality of phase shifters, and a signal combined by the combiner. Receiver, receiving phase setting means for setting the excitation phase of the element antenna, and setting the phase offset amount to be added to the excitation phase set by the excitation phase setting means, and setting the number of times to add the phase offset amount Offset setting means, a phase offset means for repeatedly adding a phase offset amount to the excitation phase set by the excitation phase setting means until the number of times set by the offset setting means, and a phase offset amount by the phase offset means Is added to the excitation phase, the phase shift states of the plurality of phase shifters are changed according to the excitation phase. Each time the phase shift state is controlled by the phase shift state control means, the signal received by the receiver is accumulated and the time average of the signal is calculated. It is to be calculated.

  According to the present invention, the phase offset unit that repeatedly adds the phase offset amount to the excitation phase set by the excitation phase setting unit until the number of times set by the offset setting unit is reached, and the phase offset amount by the phase offset unit Phase shift state control means for controlling the phase shift states of a plurality of phase shifters according to the excitation phase each time is added to the excitation phase. Each time it is controlled, the signal received by the receiver is accumulated, and the time average of the signal is calculated. Therefore, the excitation amplitude phase generated in each phase shift state of the element antennas constituting the phased array antenna There is an effect that the influence of the error can be reduced.

It is a block diagram which shows the antenna apparatus by Embodiment 1 of this invention. It is a flowchart which shows the processing content (antenna excitation method) of the antenna apparatus by Embodiment 1 of this invention. It is a timing chart which shows each process of the time direction in an antenna device. It is a block diagram which shows the antenna apparatus by Embodiment 2 of this invention. It is a flowchart which shows the processing content (antenna excitation method) of the antenna device by Embodiment 2 of this invention. It is a block diagram which shows the antenna apparatus by Embodiment 3 of this invention. It is a flowchart which shows the processing content (antenna excitation method) of the antenna device by Embodiment 3 of this invention. It is a block diagram which shows the phase shifter control apparatus 6 of the antenna apparatus by Embodiment 4 of this invention. It is explanatory drawing which shows the processing content of the quantization excitation phase setting part.

Embodiment 1 FIG.
1 is a block diagram showing an antenna apparatus according to Embodiment 1 of the present invention.
In FIG. 1, a phased array antenna 1 is composed of K element antennas 2-k (k = 1, 2, 3,..., K). k (k = 1, 2, 3,..., K) are connected.
The phase shifter 3-k performs a process of changing the phase of the high-frequency signal (radio wave) incident from the element antenna 2-k according to the excitation phase indicated by the phase shifter control signal output from the phase shifter control device 6. To do.
The synthesizer 4 synthesizes the high-frequency signals output from the phase shifters 3-1 to 3 -K, and performs a process of outputting the combined high-frequency signal to the receiver 5.

The receiver 5 detects the combined high-frequency signal output from the combiner 4 and converts the high-frequency signal into, for example, a baseband digital signal (hereinafter referred to as “digital reception data”). Here, an example in which a high-frequency signal is converted into digital reception data will be described. However, any conversion is possible as long as the signal is converted into a signal for signal processing in the subsequent stage, and the present invention is not limited to conversion into digital reception data.
The phase shifter control device 6 is composed of, for example, a semiconductor integrated circuit on which a CPU is mounted, a one-chip microcomputer, or the like, and controls a phase shift state of the phase shifter 3-k to thereby obtain a desired phased array. This is a device for realizing the radiation pattern of the antenna 1.

The excitation phase setting unit 7 is configured by a man-machine interface such as a mouse or a keyboard, for example, and performs a process of setting a common excitation phase between the element antennas 2-1 to 2-K under the operation of the user. The excitation phase setting unit 7 constitutes excitation phase setting means.
The phase offset amount setting unit 8 includes, for example, a man-machine interface, and performs a process of setting a phase offset amount to be added to the excitation phase set by the excitation phase setting unit 7 under a user operation.
The phase offset number setting unit 9 is configured by, for example, a man-machine interface, and performs processing for setting a phase offset number that is the number of times of adding the phase offset amount set by the phase offset amount setting unit 8 under the operation of the user. carry out.
The phase offset amount setting unit 8 and the phase offset number setting unit 9 constitute offset setting means.
Here, an example in which the excitation phase setting unit 7, the phase offset amount setting unit 8, and the phase offset number setting unit 9 are configured by a man-machine interface is shown, but the present invention is not limited to this. It may be configured by a communication device or the like that receives information indicating the set value, and set an excitation phase or the like according to the information.

Each time the phase offset unit 10 receives a control signal indicating the update timing of the phase shifter 3-k from the excitation time control unit 13, the phase offset number setting unit 9 with respect to the excitation phase set by the excitation phase setting unit 7 is used. The process of adding the phase offset amount set by the phase offset amount setting unit 8 is performed until the number of phase offsets set by (1) is reached. The phase offset unit 10 constitutes phase offset means.
Each time the phase offset amount is added to the excitation phase by the phase offset unit 10, the phase shifter control signal output unit 11 outputs a phase shifter control signal indicating the excitation phase to the phase shifters 3-1 to 3 -K. Perform the process. The phase shifter control signal output unit 11 constitutes a phase shift state control means.

The time average processing unit 12 is composed of, for example, a semiconductor integrated circuit on which a CPU is mounted, or a one-chip microcomputer. Every time a control signal indicating the storage timing of digital reception data is received from the excitation time control unit 13, The digital reception data output from the receiver 5 is accumulated, and a process for calculating a time average of the digital reception data is performed. The time average processing unit 12 constitutes a time average means.
The excitation time control unit 13 is composed of, for example, a semiconductor integrated circuit on which a CPU is mounted, or a one-chip microcomputer, and the control period of the phase shift state in the phase shifter 3-k and the time average processing unit 12 In order to synchronize with the time average period, a control signal indicating the update timing of the phase shifter 3-k is output to the phase offset unit 10 and control indicating the accumulation timing of the digital reception data output from the receiver 5 A process of outputting the signal to the time average processing unit 12 is performed.

In the example of FIG. 1, each of the phased array antenna 1, the receiver 5, the phase shifter control device 6, the time average processing unit 12, and the excitation time control unit 13 that are components of the antenna device is configured by dedicated hardware. However, a part of the antenna device may be configured by a computer.
For example, when the phase shifter control device 6, the time average processing unit 12 and the excitation time control unit 13 are configured as a computer as a part of the antenna device, the phase shifter control device 6, the time average processing unit 12 and the excitation A program describing the processing contents of the time control unit 13 may be stored in the memory of a computer, and the CPU of the computer may execute the program stored in the memory.
FIG. 2 is a flowchart showing the processing contents (antenna excitation method) of the antenna device according to Embodiment 1 of the present invention.

Next, the operation will be described.
For example, a high-frequency signal (radio wave) arriving from an object to be observed is incident from an element antenna 2-k constituting the phased array antenna 1 and input to the phase shifters 3-1 to 3-K.
When the high-frequency signal incident from the element antenna 2-k is input to the phase shifters 3-1 to 3 -K, according to the excitation phase indicated by the phase shifter control signal output from the phase shifter control device 6 described later. The phase of the high frequency signal is changed, and the high frequency signal after the phase change is output to the synthesizer 4.

When the synthesizer 4 receives the high-frequency signals after the phase change from the phase shifters 3-1 to 3 -K, the synthesizer 4 synthesizes the high-frequency signals and outputs the combined high-frequency signal to the receiver 5.
When receiving the combined high-frequency signal from the combiner 4, the receiver 5 detects the high-frequency signal and converts the high-frequency signal into, for example, digital received data that is a baseband digital signal. For example, if the receiver 5 is a digital receiver, a digital signal after A / D conversion is output.

The phase shifter control device 6 controls the phase shift state of the phase shifter 3-k in order to realize a desired radiation pattern of the phased array antenna 1.
Hereinafter, the processing content of the phase shifter control apparatus 6 is demonstrated concretely.

First, the excitation phase setting unit 7 of the phase shifter control device 6 determines the excitation phase β _k (k = 1, 2,..., K, K is the number of element antennas) necessary for realizing a desired radiation pattern. Setting is made (step ST1 in FIG. 2).
The phase offset amount setting unit 8 sets the phase offset amount φ to be added to the excitation phase β _k set by the excitation phase setting unit 7 (step ST2).
The phase offset number setting unit 9 sets a phase offset number M that is the number of times the phase offset amount φ set by the phase offset amount setting unit 8 is added to the excitation phase β _k (step ST2).
The number M of phase offsets corresponds to the number of times of changing the phase shift state of the phase shifters 3-1 to 3 -K.

Here, the phase offset amount φ set by the phase offset amount setting unit 8 is the minimum phase displacement amount whose phase can be changed by the phase shifters 3-1 to 3 -K. When the phase range in which the phase can be changed by 1 to 3−K is, for example, 2π [rad], the phase offset amount φ so that the phase offset amount φ × the number of phase offsets M is 2π [rad]. And the number M of phase offsets is set.
For example, if the phase shifters 3-1 to 3 -K are Nb-bit digital phase shifters, the digital phase shifter has 2 ^Nb quantized phase shift states, so that the phase can be changed. If the phase range is 2π [rad], the phase offset amount φ is 2π / 2 ^Nb .

The excitation time control unit 13 indicates the update timing of the phase shifter 3-k in order to synchronize the control period of the phase shift state in the phase shifter 3-k and the time average period in the time average processing unit 12. The control signal is output to the phase offset unit 10, and the control signal indicating the accumulation timing of the digital reception data output from the receiver 5 is output to the time average processing unit 12.
In addition, when the number of high-frequency signals accumulated reaches the number of phase offsets M, the excitation time control unit 13 outputs a time average calculation command to the time average processing unit 12.

When the phase offset unit 10 receives a control signal indicating the update timing of the phase shifter 3-k from the excitation time control unit 13, the excitation set by the excitation phase setting unit 7 as shown in the following equation (1). The phase offset amount φ set by the phase offset amount setting unit 8 is added to the phase β _k , and the offset value as the addition result is set as a new excitation phase θ _{k, m} (step ST3).
In the phase offset unit 10, the number m (m = 1, 2,..., M) of the addition processing of the phase offset amount φ reaches the phase offset number M set by the phase offset number setting unit 9. Every time the control signal indicating the update timing of the phase shifter 3-k is received, the addition process of the phase offset amount φ is performed.

Each time the phase offset unit 10 sets a new excitation phase θ _{k, m} , the phase shifter control signal output unit 11 sends a phase shifter control signal indicating the excitation phase θ _{k, m} to the phase shifter 3-k. (Step ST4).
Thereby, the phase shifters 3-1 to 3 -K perform the element antenna 2 according to the excitation phases θ _{1, m to} θ _{K, m} indicated by the phase shifter control signal output from the phase shifter control device 6. The phase of the high-frequency signal incident from _k is changed. As described above, the excitation phase β _k is a set value common to the element antennas 2-1 to 2-K, and the phase offset amount φ is also the element. This is a common setting value for the antennas 2-1 to 2-K. For this reason, even if the phase of the high-frequency signal is changed according to the excitation phases θ _{1, m to} θ _{K, m} , it is between the element antennas 2-1 to 2-K (between the phase shifters 3-1 to 3-K. ) Relative phase difference is unchanged.
Therefore, even if the phase shift state of the phase shifter 3-k is changed, the amplitude characteristic (envelope) of the radiation pattern of the phased array antenna 1 remains unchanged, and the antenna gain is constant in principle.

However, even if the phase shift state of the phase shifter 3-k is changed, a pass amplitude error and a pass phase shift error are generated.
Assuming that the passing amplitude error generated in each phase shift state is Δa _{k, m} and the passing phase shift error is Δθ _{k, m} , the actual excitation phase shift θ ′ _{k, m in the} phase shifter 3-k is expressed by the following equation ( 2).

The high frequency signal whose phase has been changed by the phase shifters 3-1 to 3 -K is input to the synthesizer 4, and the K high frequency signals are synthesized by the synthesizer 4 as described above.
The combined high-frequency signal is input to the receiver 5, and as described above, the combined high-frequency signal is detected by the receiver 5, and the high-frequency signal is converted into digital received data, for example, a baseband digital signal. The

The time average processing unit 12 stores the digital reception data output from the receiver 5 every time it receives a control signal indicating the storage timing of the digital reception data from the excitation time control unit 13 (step ST5).
That is, the time average processing unit 12 stores the digital reception data output from the receiver 5 until the number of digital reception data storage reaches the number of phase offsets M.
When the number of stored digital reception data reaches the number of phase offsets M and the time average processing unit 12 receives a time average calculation command from the excitation time control unit 13 (step ST6), the time average processing unit 12 stores the M digital stored data. By dividing the received data by the number of phase offsets M, the time average (time integration) of the digital received data is calculated (step ST7).

Further, when calculating the time average (time integration) of the digital reception data, the phase offset amount φ is known. Therefore, in order to remove the influence of the phase offset, the reverse of canceling the influence on each digital reception data is performed. You may make it take a time average, correct | amending a phase.

Generally, it is known that the amplitude phase error in hardware such as a phase shifter follows a so-called normal distribution with an average of 0 and a standard deviation of σ, and the influence of the passing phase shift error Δθ _{k, m} is M times. Is reduced by the averaging effect. The same averaging effect can be obtained for the passing amplitude error.

Here, FIG. 3 is a timing chart showing each process in the time direction in the antenna device.
As shown in FIG. 3A, a situation is assumed in which the element antenna 2-k repeatedly receives a signal s having the same waveform.
The switching timing of the phase shift state of the phase shifter 3-k is synchronized with the period of the reception signal s as shown in FIG.

In this case, when m = 1, when the phase shift state of the phase shifter 3-k connected to the element antenna 2-k is set to θ _{k, 1} , as shown in FIG. , Y_1 is obtained as an output signal of the receiver 5.
Thereafter, when the phase shift state θ _{k, m} is updated in synchronization with the period of the received signal s, y_m is obtained as the output signal of the receiver 5, and the output signal y_m of the receiver 5 is accumulated.
Finally, M output signals y_1 to y_M of the receiver 5 are accumulated, and an output y_ave obtained by time-average processing of the M output signals y_1 to y_M is obtained.
In the example of FIG. 3, the received signal s is intermittent and the period T and the holding period T1 of the phase shift state are the same. However, the present invention is not limited to this, and for example, the received signal s for each phase shift state. If the same part can be received, there may be an update delay of the phase shifter, and T1 may be shorter than T.

As can be seen from the above, according to the first embodiment, the excitation phase β _k set by the excitation phase setting unit 7 reaches the phase offset number M set by the phase offset number setting unit 9. Then, by adding the phase offset amount φ set by the phase offset amount setting unit 8, the phase offset unit 10 that repeatedly sets a new excitation phase θ _{k, m} and the new excitation phase set by the phase offset unit 10 a phase shifter control signal output unit 11 that controls the phase shift state of the phase shifter 3 _-m according to θ _{k, m} , and the time average processing unit 12 uses the phase shifter control signal output unit 11 to Since the digital reception data output from the receiver 5 is accumulated every time is controlled and the time average of the digital reception data is calculated, the phased array antenna is configured. That element will be able to reduce the influence of the excitation amplitude and phase errors caused by the phase state of the antenna 2-k, there is an effect that more accurate amplitude phase control possible antenna device is obtained.

In the first embodiment, the time average processing unit 12 calculates the time average of the digital reception data by dividing the accumulated M digital reception data by the number M of phase offsets. , The number of data samples of M digital received data stored is L, discrete Fourier transform is performed on the data size of M × L, and the highest value among the discrete Fourier transform results, that is, the peak The output point at which is detected may be used as a result of time averaging.
Note that when M × L is a power of two, fast Fourier transform (FFT) can be applied.

Embodiment 2. FIG.
FIG. 4 is a block diagram showing an antenna apparatus according to Embodiment 2 of the present invention. In the figure, the same reference numerals as those in FIG.
The transmitter 21 generates a high-frequency signal that is a transmission signal, and performs processing for outputting the high-frequency signal to the phased array antenna 1.
The distributor 22 of the phased array antenna 1 performs a process of distributing the high-frequency signal output from the transmitter 21 to the phase shifters 3-1 to 3 -K.

The receiving antenna 31 receives high-frequency signals radiated from the element antennas 2-1 to 2-K of the phased array antenna 1.
In the example of FIG. 4, the reception antenna 31 is installed at a different location from the phased array antenna 1, but may be installed at the same location as the phased array antenna 1 or in a nearby location.
In the case where the transmitting side and the receiving side are separated from each other, it is not realistic to lay the wiring connecting the two. In this second embodiment, the receiving antenna 31 is arranged separately from the phased array antenna 1 on the transmitting side. ing.
The receiver 32 detects a high-frequency signal incident from the reception antenna 31 and performs a process of converting the high-frequency signal into digital reception data that is a baseband digital signal, for example.
The receiving antenna 31 and the receiver 32 constitute signal receiving means.

The excitation time storage unit 33 is configured by a storage device such as a RAM or a hard disk, for example, and the update timing of the phase shifter 3-k indicated by the control signal output from the excitation time control unit 13 and the number of phase offsets are set in advance. The number of phase offsets M set by the unit 9 is stored.
The time average processing unit 34 is composed of, for example, a semiconductor integrated circuit on which a CPU is mounted, a one-chip microcomputer, or the like, and is updated at each update timing of the phase shifter 3-k stored in the excitation time storage unit 33. The digital reception data output from the receiver 32 is accumulated, and a process for calculating the time average of the digital reception data is performed.
The excitation time storage unit 33 and the time average processing unit 34 constitute time averaging means.

In the example of FIG. 4, the phased array antenna 1, the transmitter 21, the phase shifter control device 6, the excitation time control unit 13, the reception antenna 31, the receiver 32, the excitation time storage unit 33, and the time that are components of the antenna device Although each of the average processing units 34 is assumed to be configured with dedicated hardware, a part of the antenna device may be configured with a computer.
For example, when the phase shifter control device 6 and the excitation time control unit 13 are configured as a computer as a part of the antenna device, the processing contents of the phase shifter control device 6 and the excitation time control unit 13 are described. The program may be stored in the memory of the computer, and the CPU of the computer may execute the program stored in the memory.
FIG. 5 is a flowchart showing the processing contents (antenna excitation method) of the antenna device according to the second embodiment of the present invention.

In the first embodiment, an example in which the antenna device receives a high-frequency signal has been described. However, a high-frequency signal radiated from the phased array antenna 1 of the antenna device is a receiving antenna that is installed at a location different from the phased array antenna 1. When 31 is incident, the time average processing unit 34 may calculate the time average of the high-frequency signal.
In this case, the input / output relationship of the high-frequency signal in the phased array antenna 1 is reversed as compared with the first embodiment, but the basic operation is not changed.
At this time, the phase shifter control device 6 and the excitation time control unit 13 also perform the same operation as in the first embodiment, but since the time average processing unit 12 is not mounted, the excitation time control unit 13 performs time averaging. Processing for controlling the processing unit 12 is not performed.

Next, the operation will be described.
The transmitter 21 generates a high-frequency signal that is a transmission signal, and outputs the high-frequency signal to the phased array antenna 1.
When the distributor 22 of the phased array antenna 1 receives a high-frequency signal from the transmitter 21, the distributor 22 distributes the high-frequency signal to the phase shifters 3-1 to 3 -K.

In order to realize a desired radiation pattern of the phased array antenna 1, the phase shifter control device 6 controls the phase shift state of the phase shifter 3-k as in the first embodiment.
That is, the excitation phase setting unit 7 of the phase shifter control device 6 performs the excitation phase β _k (k = 1, 2,..., K) necessary for realizing a desired radiation pattern, as in the first embodiment. , K is the number of element antennas) (step ST11 in FIG. 5). This excitation phase β _k is a set value common to the element antennas 2-1 to 2-K.
Similarly to the first embodiment, the phase offset amount setting unit 8 sets the phase offset amount φ added to the excitation phase β _k set by the excitation phase setting unit 7 (step ST12).
Similarly to the first embodiment, the phase offset number setting unit 9 sets a phase offset number M that is the number of times the phase offset amount φ set by the phase offset amount setting unit 8 is added to the excitation phase β _k. (Step ST12).

When the phase offset unit 10 receives the control signal indicating the update timing of the phase shifter 3-k from the excitation time control unit 13, the excitation set by the excitation phase setting unit 7 as shown in the above equation (1). The phase offset amount φ set by the phase offset amount setting unit 8 is added to the phase β _k , and the offset value as the addition result is set as a new excitation phase θ _{k, m} (step ST13).
In the phase offset unit 10, the number m (m = 1, 2,..., M) of the addition processing of the phase offset amount φ reaches the phase offset number M set by the phase offset number setting unit 9. Every time the control signal indicating the update timing of the phase shifter 3-k is received, the addition process of the phase offset amount φ is performed.

Each time the phase offset unit 10 sets a new excitation phase θ _{k, m} , the phase shifter control signal output unit 11 sends a phase shifter control signal indicating the excitation phase θ _{k, m} to the phase shifter 3-k. (Step ST14).
Thereby, the phase shifters 3-1 to 3 -K perform the element antenna 2 according to the excitation phases θ _{1, m to} θ _{K, m} indicated by the phase shifter control signal output from the phase shifter control device 6. The phase of the high-frequency signal radiated from _k is changed. As described above, the excitation phase β _k is a set value common to the element antennas 2-1 to 2-K, and the phase offset amount φ is also the element. This is a common setting value for the antennas 2-1 to 2-K. For this reason, even if the phase of the high-frequency signal is changed according to the excitation phases θ _{1, m to} θ _{K, m} , it is between the element antennas 2-1 to 2-K (between the phase shifters 3-1 to 3-K. ) Relative phase difference is unchanged.
Therefore, even if the phase shift state of the phase shifter 3-k is changed, the amplitude characteristic (envelope) of the radiation pattern of the phased array antenna 1 remains unchanged, and the antenna gain is constant in principle.

When the phase shifters 3-1 to 3 -K receive the high-frequency signal distributed by the distributor 22, the excitation phases θ _{1, m to} θ indicated by the phase shifter control signal output from the phase shifter control device 6. The phase of the high-frequency signal is changed according to _{K, m, and} the high-frequency signal after the phase change is output to the element antennas 2-1 to 2-K.
Thereby, the high-frequency signal after the phase change is radiated from the element antennas 2-1 to 2-K of the phased array antenna 1 (step ST15).

The receiving antenna 31 receives a high-frequency signal radiated from the element antennas 2-1 to 2-K of the phased array antenna 1.
The receiver 32 detects the high-frequency signal incident from the reception antenna 31 and converts the high-frequency signal into digital reception data that is, for example, a baseband digital signal (step ST16).

The time average processing unit 34 refers to the stored contents of the excitation time storage unit 33 to grasp the update timing of the phase shifter 3-k and outputs it from the receiver 32 at each update timing of the phase shifter 3-k. The received digital reception data is stored (step ST17).
That is, the time average processing unit 34 stores the digital reception data output from the receiver 32 until the number of digital reception data storage reaches the number of phase offsets M.
When the accumulated number of digital reception data reaches the number of phase offsets M (step ST18), the time average processing unit 34 divides the accumulated M digital reception data by the number of phase offsets M, thereby obtaining the digital reception data. The time average (time integration) of the data is calculated (step ST19).

Further, when calculating the time average (time integration) of the digital reception data, the phase offset amount φ is known, so that in order to remove the influence of the phase offset, similarly to the time average processing unit 12 of FIG. For digital received data, a time average may be taken while correcting the opposite phase that cancels the influence.
Generally, it is known that the amplitude phase error in hardware such as a phase shifter follows a so-called normal distribution with an average of 0 and a standard deviation of σ, and the influence of the passing phase shift error Δθ _{k, m} is M times. Is reduced by the averaging effect. The same averaging effect can be obtained for the passing amplitude error.

As is apparent from the above, according to the second embodiment, the time average processing unit 34 outputs from the receiver 32 at every update timing of the phase shifter 3-k stored in the excitation time storage unit 33. Since the received digital received data is stored and the time average of the digital received data is calculated, each phase shift of each of the element antennas 2-k constituting the phased array antenna is performed as in the first embodiment. The influence of the excitation amplitude phase error generated in the state can be reduced, and there is an effect that an antenna device capable of more precise amplitude phase control can be obtained.
In the second embodiment, the time average processing unit 34 accumulates the digital reception data output from the receiver 32 at each update timing of the phase shifter 3-k stored in the excitation time storage unit 33. However, the sender and receiver are not completely synchronized. However, since the high-frequency signal radiated from the transmission side is received according to a predetermined procedure, the same result as when the transmission side and the reception side are completely synchronized can be obtained.

In the second embodiment, the time average processing unit 34 calculates the time average of the digital reception data by dividing the accumulated M digital reception data by the number M of phase offsets. , The number of data samples of M digital received data stored is L, discrete Fourier transform is performed on the data size of M × L, and the highest value among the discrete Fourier transform results, that is, the peak The output point at which is detected may be used as a result of time averaging.
Note that when M × L is a power of two, fast Fourier transform (FFT) can be applied.

Embodiment 3 FIG.
6 is a block diagram showing an antenna apparatus according to Embodiment 3 of the present invention. In the figure, the same reference numerals as those in FIGS.
The combiner / distributor 40 distributes the high-frequency signal output from the transmitter 21 to the phase shifters 3-1 to 3 -K, and combines the high-frequency signal output from the phase shifters 3-1 to 3 -K. Then, a process of outputting the synthesized high frequency signal to the receiver 5 is performed.

  In the first embodiment, the example in which the element antenna 2-k constituting the phased array antenna 1 receives a high-frequency signal (radio wave) coming from the target object to be observed is shown. After the element antenna 2-k that radiates a high-frequency signal (radio wave), for example, the element antenna 2 that constitutes the phased array antenna 1 is used to reflect the reflected wave of the high-frequency signal that is reflected by the target object to be observed and returned. -K may be incident.

Next, the operation will be described.
The transmitter 21 generates a high-frequency signal that is a transmission signal, and outputs the high-frequency signal to the phased array antenna 1 as in the second embodiment.
When the synthesizer / distributor 40 of the phased array antenna 1 receives a high-frequency signal from the transmitter 21, the synthesizer / distributor 40 distributes the high-frequency signal to the phase shifters 3-1 to 3 -K.

The phase shifter control device 6 controls the phase shift state of the phase shifter 3-k, as in the first and second embodiments, in order to realize a desired radiation pattern of the phased array antenna 1.
That is, the excitation phase setting unit 7 of the phase shifter control device 6 sets the excitation phase β _k necessary for realizing a desired radiation pattern, similarly to the first and second embodiments (step ST21 in FIG. 7). . This excitation phase β _k is a set value common to the element antennas 2-1 to 2-K. The same set value is used when transmitting and receiving a high-frequency signal.
Similarly to the first and second embodiments, the phase offset amount setting unit 8 sets the phase offset amount φ to be added to the excitation phase β _k set by the excitation phase setting unit 7 (step ST22).
Similarly to the first and second embodiments, the phase offset number setting unit 9 sets the phase offset number M, which is the number of times the phase offset amount φ set by the phase offset amount setting unit 8 is added to the excitation phase _βk. Set (step ST12).

When the phase offset unit 10 receives a control signal indicating the update timing of the phase shifter 3-k from the excitation time control unit 13, the excitation set by the excitation phase setting unit 7 as in the first and second embodiments. The phase offset amount φ set by the phase offset amount setting unit 8 is added to the phase β _k , and the offset value as the addition result is set as a new excitation phase θ _{k, m} (step ST23).

When the phase offset unit 10 sets a new excitation phase θ _{k, m} , the phase shifter control signal output unit 11 outputs a phase shifter control signal indicating the excitation phase θ _{k, m} to the phase shifter 3-k. (Step ST24).
Thereby, the phase shifters 3-1 to 3 -K perform the element antenna 2 according to the excitation phases θ _{1, m to} θ _{K, m} indicated by the phase shifter control signal output from the phase shifter control device 6. The phase of the high-frequency signal radiated from _k is changed. As described above, the excitation phase β _k is a set value common to the element antennas 2-1 to 2-K, and the phase offset amount φ is also the element. This is a common setting value for the antennas 2-1 to 2-K. For this reason, even if the phase of the high-frequency signal is changed according to the excitation phases θ _{1, m to} θ _{K, m} , it is between the element antennas 2-1 to 2-K (between the phase shifters 3-1 to 3-K. ) Relative phase difference is unchanged.
Therefore, even if the phase shift state of the phase shifter 3-k is changed, the amplitude characteristic (envelope) of the radiation pattern of the phased array antenna 1 remains unchanged, and the antenna gain is constant in principle.

When the phase shifters 3-1 to 3 -K receive the high-frequency signal distributed by the combiner / distributor 40, the excitation phase θ _{1, m} ˜ indicated by the phase shifter control signal output from the phase shifter control device 6. The phase of the high-frequency signal is changed according to θ _{K, m, and} the high-frequency signal after the phase change is output to the element antennas 2-1 to 2-K.
Thereby, the high-frequency signal after the phase change is radiated from the element antennas 2-1 to 2-K of the phased array antenna 1 (step ST25).
A part of the high-frequency signal radiated from the element antennas 2-1 to 2-K of the phased array antenna 1 is reflected (or scattered) by the target to be observed and returns to the phased array antenna 1.
The element antennas 2-1 to 2-K of the phased array antenna 1 receive a high-frequency signal that has been reflected by the target and returned.

The phase offset unit 10 receives the high-frequency signals from the element antennas 2-1 to 2-K of the phased array antenna 1 and then returns the high-frequency signals reflected by the target object to the element antennas 2-1 to 2-K. Is added to the excitation phase β _k set by the excitation phase setting unit 7 and the phase offset amount φ set by the phase offset amount setting unit 8 is added. A certain offset value is set as a new excitation phase θ _{k, m} (step ST26).

When the phase offset unit 10 sets a new excitation phase θ _{k, m} , the phase shifter control signal output unit 11 outputs a phase shifter control signal indicating the excitation phase θ _{k, m} to the phase shifter 3-k. (Step ST27).
Thereby, the phase shifters 3-1 to 3 -K perform the element antenna 2 according to the excitation phases θ _{1, m to} θ _{K, m} indicated by the phase shifter control signal output from the phase shifter control device 6. The phase of the high-frequency signal incident from _k is changed. As described above, the excitation phase β _k is a set value common to the element antennas 2-1 to 2-K, and the phase offset amount φ is also the element. This is a common setting value for the antennas 2-1 to 2-K. For this reason, even if the phase of the high-frequency signal is changed according to the excitation phases θ _{1, m to} θ _{K, m} , it is between the element antennas 2-1 to 2-K (between the phase shifters 3-1 to 3-K. ) Relative phase difference is unchanged.
Therefore, even if the phase shift state of the phase shifter 3-k is changed, the amplitude characteristic (envelope) of the radiation pattern of the phased array antenna 1 remains unchanged, and the antenna gain is constant in principle.

When the phase shifters 3-1 to 3 -K receive the high-frequency signal incident from the element antenna 2-k (the high-frequency signal returned by being reflected by the target), the phase shifter 3-1 to 3 -K is output from the phase shifter control device 6. The phase of the high-frequency signal is changed according to the excitation phases θ _{1, m to} θ _{K, m} indicated by the phase shifter control signal, and the high-frequency signal after the phase change is output to the combiner / distributor 40.
When the combiner / distributor 40 receives the high-frequency signals after the phase change from the phase shifters 3-1 to 3 -K, the combiner / distributor 40 combines the high-frequency signals and outputs the combined high-frequency signal to the receiver 5.
When receiving the combined high-frequency signal from the combiner / distributor 40, the receiver 5 detects the high-frequency signal and converts the high-frequency signal into, for example, digital received data that is a baseband digital signal (step ST28).

Similar to the first embodiment, the time average processing unit 12 stores the digital reception data output from the receiver 5 each time it receives a control signal indicating the storage timing of the digital reception data from the excitation time control unit 13. (Step ST29).
That is, the time average processing unit 12 stores the digital reception data output from the receiver 5 until the number of digital reception data storage reaches the number of phase offsets M / 2.
When the number of stored digital reception data reaches the number of phase offsets M / 2 and the time average processing unit 12 receives a time average calculation command from the excitation time control unit 13 (step ST30), the time average processing unit 12 stores the stored M / By dividing the two digital reception data by the number of phase offsets M / 2, the time average (time integration) of the digital reception data is calculated (step ST31).

  As is apparent from the above, according to the third embodiment, two phase offsets are executed in one transmission process and reception process, and when the number of stored digital reception data becomes M / 2. The number m of phase offset executions reaches the number M of phase offsets. For this reason, a time average (time integration) calculation process is performed when the number of accumulated digital reception data reaches M / 2. As a result, there is an effect that the time-averaged data size can be reduced to ½ compared to the first embodiment.

In the third embodiment, the example in which the excitation phase β _k and the phase offset amount φ are the same set values at the time of transmission and reception of the high-frequency signal is shown. However, the excitation phase β _k and the phase offset at the time of transmission of the high-frequency signal are shown. The amount φ may be set to a value different from the excitation phase β _k and the phase offset amount φ at the time of receiving a high-frequency signal.

Embodiment 4 FIG.
FIG. 8 is a block diagram showing a phase shifter control device 6 for an antenna device according to Embodiment 4 of the present invention. In the figure, the same reference numerals as those in FIG.
The quantized phase shift state storage unit 51 is composed of a storage device such as a RAM or a hard disk, for example, and stores passage phase shift amounts in a plurality of quantized phase shift states in the phase shifter 3-k. The quantized phase shift state storage unit 51 constitutes an offset setting unit.
The quantization excitation phase setting unit 52 selects the excitation phase β set by the excitation phase setting unit 7 from the passing phase shift amounts in the plurality of quantization phase shift states stored by the quantization phase shift state storage unit 51. Each time a phase shift candidate point closest to _k (hereinafter referred to as “first passing phase shift amount”) is selected and a control signal indicating the update timing of the phase shifter 3-k is received from the excitation time control unit 13, A process of setting a phase shift candidate point adjacent to the first passage phase shift amount (hereinafter referred to as “second passage phase shift amount”) as the excitation phase θ _{k, m} is performed. The quantization excitation phase setting unit 52 constitutes phase offset means.

In the first to third embodiments, when the phase offset unit 10 receives the control signal indicating the update timing of the phase shifter 3-k from the excitation time control unit 13, the excitation phase β set by the excitation phase setting unit 7. _The phase offset amount φ set by the phase offset amount setting unit 8 is added to _k, and the offset value that is the addition result is set as a new excitation phase θ _{k, m.} In the fourth embodiment, an example will be described in which the quantization excitation phase setting unit 52 sets the excitation phase θ _{k, m} as follows.
FIG. 9 is an explanatory diagram showing the processing contents of the quantization excitation phase setting unit 52.

When the phase shifter 3-k is composed of an Nb-bit digital phase shifter, the number of possible phase shift states I is 2 ^Nb . Therefore, the minimum value of the phase offset amount φ and the upper limit value of the number of offsets M are clearly determined.
The horizontal axis of FIG. 9 is a number indicating the phase shifter 3-k (k = 1, 2,..., K), and the vertical axis is the passing phase shift amount (quantization) of the phase shifter 3-k. Passed phase shift amount).
In FIG. 9, dotted circles (circled with reference numeral 60) indicate possible phase shift states (hereinafter referred to as “phase shift candidate points”), and a maximum of I points for each phase shifter. There is a state. The quantized phase shift state storage unit 51 stores passage phase shift amounts in the plurality of quantized phase shift states.

The quantization excitation phase setting unit 52 receives the excitation phase β _k set by the excitation phase setting unit 7.
Here, for convenience of explanation, it is assumed that the excitation phase β _k set by the excitation phase setting unit 7 is represented by a cross marked with a reference numeral 61 in FIG.
The quantized excitation phase setting unit 52 sets the excitation phase set by the excitation phase setting unit 7 from the passing phase shift amounts in the plurality of quantized phase shift states stored by the quantized phase shift state storage unit 51. The first passing phase shift amount that is the closest phase shift candidate point to β _k (excitation phase indicated by ×) is selected.
In the example of FIG. 9, a solid line (circled with a symbol 62) is selected as the first passing phase shift amount of the phase shifter 3-k.

When the quantization excitation phase setting unit 52 selects the first passing phase shift amount (O marked with reference numeral 62) of the phase shifter 3-k, the first passing phase shift amount is converted into the first excitation phase θ _{k. , m} .
Phase shifter control signal output unit 11, when the phase offset section 10 sets the initial excitation phase theta _{k, m,} similarly to the first to third embodiments, the phase shifter showing the excitation phase theta _{k, m} The control signal is output to the phase shifter 3-k.

Next, when the quantization excitation phase setting unit 52 receives a control signal indicating the update timing of the phase shifter 3-k from the excitation time control unit 13, the phase shift candidate point adjacent to the first passing phase shift amount. Is set to a new excitation phase θ _{k, m} .
In the example of FIG. 9, the phase shift candidate points adjacent to the plus side (◯ marked with reference numeral 63) are set as the new excitation phase θ _{k, m} with respect to the first passing phase shift amount. Yes.
Here, the phase shift candidate points adjacent on the plus side are set to the new excitation phase θ _{k, m} , but the passing phase shift amounts of all the phase shifters 3 may be offset by the same value. The phase shift candidate points adjacent on the minus side may be set to a new excitation phase θ _{k, m} .
Phase shifter control signal output unit 11, when the phase offset section 10 sets a new excitation phase theta _{k, m,} similarly to the first to third embodiments, the phase shifter showing the excitation phase theta _{k, m} The control signal is output to the phase shifter 3-k.

As is clear from FIG. 9, the relative phase between the phase shifters does not change between the first passage phase shift amount and the second passage phase shift amount, and the same effect as in the first to third embodiments can be obtained.
By repeating this procedure M times, selection is made up to the M-th passage phase shift amount (◯ marked with symbol 64).
Note that when M = I, time averaging using all the phase shift states is performed, and the effect of reducing the excitation error is the greatest.
As described above, phase shift processing can be simplified by determining the phase shift state of the digital phase shifter using the quantized phase shift state as a candidate point, enabling faster phase shifter control. become.

  In the present invention, within the scope of the invention, any combination of the embodiments, or any modification of any component in each embodiment, or omission of any component in each embodiment is possible. .

  1 phased array antenna, 2-1 to 2-K element antenna, 3-1 to 3-K phase shifter, 4 synthesizer, 5 receiver, 6 phase shifter controller, 7 excitation phase setting unit (excitation phase setting) Means), 8 phase offset amount setting section (offset setting means), 9 phase offset number setting section (offset setting means), 10 phase offset section (phase offset means), 11 phase shifter control signal output section (phase shift state control) Means), 12-hour average processing section (time-average means), 13 excitation time control section, 21 transmitter, 22 distributor, 31 receiving antenna (signal receiving means), 32 receiver (signal receiving means), 33 excitation time storage Part (time averaging means), 34 time average processing part (time averaging means), 40 synthesis distributor, 51 quantization phase shift state storage part (offset setting means), 52 quantization excitation position Setting unit (phase offset means) 60 phase candidate points, 61 excitation phase setting unit 7 by a set excitation phase, 62 first passes through the phase shift amount, 63 phase candidate points, 64 first M passing phase shift quantity.

Claims (9)

A plurality of phase shifters connected to the element antenna constituting the phased array antenna;
A synthesizer for synthesizing output signals of the plurality of phase shifters;
A receiver for receiving the signal synthesized by the synthesizer;
An excitation phase setting means for setting an excitation phase of the element antenna;
An offset setting means for setting a phase offset amount to be added to the excitation phase set by the excitation phase setting means, and for setting a number of times to add the phase offset amount;
Phase offset means for repeatedly adding the phase offset amount to the excitation phase set by the excitation phase setting means until reaching the number of times set by the offset setting means;
Phase shift state control means for controlling the phase shift state of the plurality of phase shifters according to the excitation phase each time a phase offset amount is added to the excitation phase by the phase offset means;
An antenna device comprising: a time averaging unit that accumulates a signal received by the receiver and calculates a time average of the signal each time the phase shift state is controlled by the phase shift state control unit. A plurality of phase shifters connected to the element antenna constituting the phased array antenna;
A transmitter that outputs a transmission signal;
A distributor for distributing a transmission signal output from the transmitter to the plurality of phase shifters;
An excitation phase setting means for setting an excitation phase of the element antenna;
An offset setting means for setting a phase offset amount to be added to the excitation phase set by the excitation phase setting means, and for setting a number of times to add the phase offset amount;
Phase offset means for repeatedly adding the phase offset amount to the excitation phase set by the excitation phase setting means until reaching the number of times set by the offset setting means;
Phase shift state control means for controlling the phase shift state of the plurality of phase shifters according to the excitation phase each time a phase offset amount is added to the excitation phase by the phase offset means;
A signal receiving means for receiving a signal radiated from an element antenna constituting the phased array antenna;
An antenna device comprising: a time averaging unit that accumulates a signal received by the signal receiving unit and calculates a time average of the signal each time the phase shift state is controlled by the phase shift state control unit. It has a transmitter that outputs a transmission signal,
The combiner combines the output signals of the plurality of phase shifters and outputs the combined signal to the receiver, while distributing the transmission signal output from the transmitter to the plurality of phase shifters. The antenna device according to claim 1.   4. The antenna apparatus according to claim 1, wherein the time averaging means performs a Fourier transform on the received signal and obtains a time average of the signal from the conversion result. The phase shifter is a digital phase shifter;
5. The phase offset amount set by the offset setting means is a minimum phase displacement amount capable of changing a phase by the phase shifter. 6. The antenna device according to item.   6. The number of times of adding the phase offset amount set by the offset setting means is a value obtained by dividing a phase range in which the phase can be changed by the phase shifter by the phase offset amount. Antenna device.   The excitation phase setting means sets an excitation phase when a signal is transmitted by the phased array antenna and an excitation phase when a signal is received by the phased array antenna to different values. Item 4. The antenna device according to Item 3. A signal combining process step in which the combiner combines the output signals of a plurality of phase shifters connected to the element antennas constituting the phased array antenna;
A signal reception processing step in which a receiver receives the signal synthesized in the signal synthesis processing step;
An excitation phase setting means for setting an excitation phase of the element antenna;
The offset setting means sets the phase offset amount to be added to the excitation phase set in the excitation phase setting processing step and sets the number of times to add the phase offset amount;
A phase offset processing step in which the phase offset means repeatedly adds the phase offset amount to the number of times set in the offset setting processing step with respect to the excitation phase set in the excitation phase setting processing step;
A phase-shift state control processing step for controlling a phase-shift state of the plurality of phase shifters in accordance with the excitation phase each time a phase offset amount is added to the excitation phase in the phase offset processing step; ,
A time average processing step for calculating a time average of the signal by storing the signal received in the signal reception processing step each time the phase shift state is controlled in the phase shift state control processing step. An antenna excitation method comprising: A signal transmission processing step in which a transmitter outputs a transmission signal; and
A signal distribution processing step in which a distributor distributes a transmission signal output from the transmitter to a plurality of phase shifters connected to an element antenna constituting a phased array antenna;
An excitation phase setting means for setting an excitation phase of the element antenna;
The offset setting means sets the phase offset amount to be added to the excitation phase set in the excitation phase setting processing step and sets the number of times to add the phase offset amount;
A phase offset processing step in which the phase offset means repeatedly adds the phase offset amount to the number of times set in the offset setting processing step with respect to the excitation phase set in the excitation phase setting processing step;
A phase-shift state control processing step for controlling a phase-shift state of the plurality of phase shifters in accordance with the excitation phase each time a phase offset amount is added to the excitation phase in the phase offset processing step; ,
A signal receiving means for receiving a signal radiated from an element antenna constituting the phased array antenna; and
A time average processing step for calculating a time average of the signal by storing the signal received in the signal reception processing step each time the phase shift state is controlled in the phase shift state control processing step. An antenna excitation method comprising:

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