JP2017224886A - Phase controller and array antenna system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a phase controller for adjusting the phase of a signal to a desired phase during communication, and to provide an array antenna.SOLUTION: A phase controller includes: a synthesizer 32 for synthesizing an input signal to a phase shifter 16 taken out by an input signal takeout section 18, and set with a phase by a reference phase shifter 21, and an output signal from the phase shifter 16 taken out by an output signal takeout section 23; a composite level detector 33 for detecting the level of a composite signal from the synthesizer 32; and a control section 40 for controlling the reference phase shifter 21 and the phase shifter 16 so that the phase of the output signal becomes a desired phase. The control section 40 controls the reference phase shifter 21 so that the phase of the input signal thus taken out becomes the inverse phase of the desired phase, and controls the phase shifter 16 so that the input signal of the inverse phase and the output signal are cancelled each other, on the basis of the level of the input signal and the level of the composite signal detected by the composite level detector 33.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a phase control device and an array antenna system.

In recent years, in wireless communication systems used for mobile phones and the like, demands for expansion of communication areas and expansion of communication capacity are increasing due to the spread of smartphones and the like. Then, utilization of the active antenna system incorporating the function of a high frequency transmitter / receiver to the base station apparatus is examined.
The active antenna system includes a plurality of antenna elements and a plurality of transmission / reception units provided corresponding to the plurality of antenna elements. For this reason, the radio signal transmitted / received for each antenna element can be controlled, and the controllability is excellent, and it is possible to provide a new service that can improve the communication environment by using this excellent controllability ( For example, see Patent Document 1).

Special table 2009-544205 gazette

In the above active antenna system, when controlling the directivity of the radio frequency signal (RF signal) transmitted from each antenna element, it is required to control the phase of the radio frequency signal with an accuracy error within ± 5 °. It is done. For this reason, for example, when the phase of a radio frequency signal of 3.5 GHz (wavelength = 85 mm) is controlled by a phase shifter, it is necessary to control with an accuracy error within 1 mm.
However, in practice, an error of about 1 mm occurs due to looseness, crossing, expansion and contraction due to temperature, etc., of connectors connecting each device such as a phase shifter and an amplifier constituting the active antenna system. For this reason, after setting the phase of the radio frequency signal with the phase shifter, it is necessary to adjust the phase of the radio frequency signal transmitted from each antenna element during communication. It is difficult to adjust.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a phase control device and an array antenna system capable of adjusting the phase of a signal to a desired phase during communication.

  A phase control device according to an aspect of the present invention is a phase control device including a phase shifter that adjusts the phase of a signal, and an input signal extraction unit that extracts an input signal to the phase shifter, A reference phase shifter for setting the phase of the input signal; an output signal extraction unit for extracting an output signal output from the phase shifter; the input signal whose phase is set by the reference phase shifter; A synthesizer for synthesizing the output signal, a synthesis level detector for detecting a synthesis level which is a level of the synthesized signal of the synthesizer, and the reference phase shifter so that the phase of the output signal becomes a desired phase. And a control unit that controls the phase shifter, and the control unit controls the reference phase shifter so that the phase of the extracted input signal is opposite to the desired phase, Inverse phase input signal and output signal The phase shifter is controlled based on the input level, which is the level of the input signal, and the synthesis level detected by the synthesis level detector so as to cancel each other out when the signals are synthesized by the synthesizer. This is a phase control device.

  An array antenna system according to an aspect of the present invention includes a plurality of antenna elements, a plurality of phase shifters that individually adjust phases of signals transmitted by the antenna elements, and a plurality of the phase shifters. An input signal extraction unit that extracts an input signal, a reference phase shifter that sets the phase of the extracted input signal, and an output signal that is output from each phase shifter and input to the corresponding antenna element A plurality of output signal extraction units, a synthesizer that synthesizes the input signal whose phase is set by the reference phase shifter, and the extracted output signal, and a synthesis level that is a level of a synthesis signal of the synthesizer. A combined level detector for detecting, and a control unit for controlling the reference phase shifter and the corresponding phase shifter so that a phase of the output signal input to the antenna element becomes a desired phase. The control unit controls the reference phase shifter so that the phase of the extracted input signal is opposite to the desired phase, and the input signal and the output signal having the opposite phase are controlled by the combiner. An array for controlling the phase shifter based on the input level, which is the level of the input signal, and the composite level detected by the composite level detector so as to cancel these two signals with each other when they are combined with each other. It is an antenna system.

  The present invention can be implemented not only as a phase control apparatus including such a characteristic processing unit, but also as a method using such characteristic processing as a step, or causing a computer to execute such characteristic processing steps. Can be realized as a program. Further, it can be realized as a semiconductor integrated circuit that realizes part or all of the phase control device.

  According to the present invention, the phase of a signal can be adjusted to a desired phase during communication.

It is a block diagram which shows a part of base station apparatus provided with the array antenna system which concerns on 1st Embodiment of this invention. It is a block diagram which shows the structure of the transmission side of an antenna system. It is a block diagram which shows the control structure of an antenna system. It is an example of the look-up table which shows the relationship between a phase, the gain corresponding to this, and a passage loss. It is a block diagram when a control part performs the control process of a phase shifter. It is a block diagram which shows the control structure of the array antenna system which concerns on 2nd Embodiment of this invention. It is a block diagram which shows the control structure of the array antenna system which concerns on 3rd Embodiment of this invention. It is a block diagram which shows the control structure of the array antenna system which concerns on 4th Embodiment of this invention.

[Description of Embodiment of the Present Invention]
First, the contents of the embodiment of the present invention will be listed and described.
(1) A phase control device according to an embodiment of the present invention is a phase control device including a phase shifter that adjusts the phase of a signal, and an input signal extraction unit that extracts an input signal to the phase shifter; A reference phase shifter for setting the phase of the extracted input signal, an output signal extraction unit for extracting an output signal output from the phase shifter, and the input signal whose phase is set by the reference phase shifter, And a synthesizer for synthesizing the extracted output signal, a synthesis level detector for detecting a synthesis level which is a level of the synthesized signal of the synthesizer, and the reference so that the phase of the output signal becomes a desired phase. And a control unit that controls the phase shifter, and the control unit controls the reference phase shifter so that the phase of the extracted input signal is opposite to the desired phase. The anti-phase input signal and the When the force signal is combined by the combiner, the phase shift is performed based on the input level which is the level of the input signal and the combined level detected by the combined level detector so as to cancel each other out. Control the instrument.

  According to the phase control device, the control unit controls the reference phase shifter so that the phase of the input signal extracted by the input signal extraction unit is opposite to the desired phase. Then, the control unit controls the phase shifter so as to cancel each other out when the input signal having the opposite phase and the output signal extracted by the output signal extraction unit are combined by the combiner. . As a result, the output signal synthesized by the synthesizer is adjusted to have an opposite phase to the input signal synthesized with the output signal, that is, in phase with the desired phase. As a result, the phase of the output signal output from the phase shifter can be set to the desired phase. Therefore, the phase of the signal can be adjusted to a desired phase during communication.

  Further, when controlling the phase shifter so as to cancel the two signals, the phase shifter is controlled based on the input level of the input signal and the composite level of the composite signal detected by the composite level detector. Therefore, for example, by controlling the phase shifter based on the ratio between the input level and the composite level, the phase shifter is set so as to cancel both signals even if the value of the input level changes greatly during communication. Can be controlled.

(2) It is preferable that the phase control device further includes an input level detector that detects an input level of the extracted input signal.
If the input level of the input signal can be grasped by the control unit, the input level detector may not be provided. However, if the input level detector is provided, the input level of the input signal extracted from the input signal extraction unit Is detected by the input level detector, the timing at which the input level of the input signal is detected can be approximated to the timing at which the input signal is input to the synthesizer. Thus, the control unit can easily control the phase shifter without considering the delay error between the two timings.

(3) In the phase control device, it is preferable that the control unit controls the phase shifter so that a ratio between the input level and the combined level is equal to or less than a threshold value.
In this case, even if the value of the input level changes greatly during communication, the control unit controls the phase shifter so that the ratio between the input level and the composite level is equal to or less than the threshold value. Can be offset.

(4) In the phase control device, the control unit weights a threshold value of the synthesis level according to the input level, and controls the phase shifter so that the synthesis level is equal to or lower than the threshold value after the weighting. May be.
In this case, even if the value of the input level changes greatly during communication, the control unit sets the threshold value to an appropriate value according to the input level, so that the both signals can be canceled easily and reliably. The phaser can be controlled.

(5) The phase control device further includes a correction unit that corrects the synthesis level, and the control unit controls the correction unit according to the input level, and the corrected synthesis level is equal to or less than a threshold value. The phase shifter may be controlled as described above.
In this case, even if the value of the input level changes greatly during communication, the control unit corrects the composite level to an appropriate value according to the input level, so that the two signals are surely canceled. Can be controlled.

(6) In the phase control device, the correction unit is an integrator that integrates the composite level, and the control unit is configured to change the integration time of the integrator according to the input level. Is preferably controlled.
In this case, the control unit can correct the synthesis level to an appropriate value by changing the integration time of the integrator in accordance with the changing input level. The phaser can be controlled.

(7) In the phase control device, the correction unit is an amplifier that amplifies the combined level, and the control unit controls the amplifier to change a gain of the amplifier according to the input level. Also good.
In this case, the control unit can correct the combined level to an appropriate value by changing the gain of the amplifier that amplifies the combined level in accordance with the changing input level. The phase shifter can be controlled to do so.

  (8) An array antenna system according to an embodiment of the present invention includes a plurality of antenna elements, a plurality of phase shifters that individually adjust phases of signals transmitted by these antenna elements, and a plurality of the phase shift elements. An input signal extraction unit that extracts an input signal to the device, a reference phase shifter that sets the phase of the extracted input signal, and an output that is output from each phase shifter and input to the corresponding antenna element A plurality of output signal extraction units that extract signals, a synthesizer that synthesizes the input signal whose phase is set by the reference phase shifter, and the extracted output signal, and a level of a synthesized signal of the synthesizer. A synthesis level detector for detecting a synthesis level, and a control for controlling the reference phase shifter and the corresponding phase shifter so that the phase of the output signal input to the antenna element becomes a desired phase. And the control unit controls the reference phase shifter so that the phase of the extracted input signal is opposite to the desired phase, and the input signal and the output signal having the opposite phase are controlled. The phase shifter is controlled based on the input level, which is the level of the input signal, and the synthesis level detected by the synthesis level detector so as to cancel each other out when the signals are synthesized by the synthesizer. To do.

According to the array antenna system, the control unit controls the reference phase shifter so that the phase of the input signal extracted by the input signal extraction unit is opposite to the desired phase. Then, the control unit uses a phase shifter so as to cancel each other when the input signal having the opposite phase and the output signal extracted by the corresponding output signal extraction unit are combined by the combiner. Control. As a result, the output signal synthesized by the synthesizer is adjusted to have an opposite phase to the input signal synthesized with the output signal, that is, in phase with the desired phase. As a result, the output signal output from each phase shifter is transmitted from the corresponding antenna element with the desired phase. Therefore, the phases of signals transmitted from the plurality of antenna elements during communication can be adjusted to desired phases, respectively.
Further, when controlling the phase shifter so as to cancel the two signals, the phase shifter is controlled based on the input level of the input signal and the composite level of the composite signal detected by the detector. For example, by controlling the phase shifter based on the ratio between the input level and the composite level, the phase shifter can be reliably canceled even if the value of the input level changes greatly during communication. Can be controlled.

[Details of the embodiment of the present invention]
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In addition, you may combine arbitrarily at least one part of embodiment described below.
[First Embodiment]
<About base station equipment>
FIG. 1 is a block diagram showing a part of a base station apparatus provided with an array antenna system according to the first embodiment of the present invention. In the figure, a base station apparatus 1 has a function as a communication apparatus that performs wireless communication with other communication apparatuses. A baseband unit (BBU) 2 and a signal transmission path ( An active antenna system 4 is provided as an array antenna system connected via an optical transmission path or an electrical transmission path 3.

The baseband unit 2 has a function of performing processing such as digital modulation / demodulation processing on a baseband signal including data transmitted and received by wireless communication, and a digital baseband signal (I / Q signal including transmission data). ) To the antenna system 4 via the signal transmission path 3.
Further, the baseband unit 2 acquires a digital baseband signal (I / Q signal) including received data, which is given from the antenna system 4 via the signal transmission path 3.

The active antenna system 4 (hereinafter also simply referred to as the antenna system 4) includes a plurality of (here, eight) antenna elements 5 for transmitting and receiving radio frequency signals, and the base station apparatus 1 is connected to other communication apparatuses. Have a function of transmitting and receiving a radio signal related to the wireless communication.
The antenna system 4 performs various signal processing on the digital baseband signal given from the baseband unit 2 to convert it into an analog radio frequency signal, and transmits it from the plurality of antenna elements 5 as a radio signal.

  The antenna system 4 converts various radio frequency signals received as radio signals by the plurality of antenna elements 5 into digital baseband signals, and converts the converted baseband signals into baseband units. Give to 2.

  In this way, the base station apparatus 1 converts the baseband signal including the transmission data into a radio frequency signal and transmits it to another communication apparatus, and receives the radio frequency signal transmitted by the other communication apparatus. A baseband signal including received data from another communication device is acquired.

<About the antenna system configuration>
FIG. 2 is a block diagram showing the configuration of the antenna system 4 on the transmission side.
The antenna system 4 includes a digital signal processing unit 8 and an analog signal processing unit 9.
The baseband signal given to the antenna system 4 as a transmission signal for wireless communication from the baseband unit 2 is subjected to digital signal processing by the digital signal processing unit 8 and then given to the analog signal processing unit 9 to obtain an analog radio frequency. And is given to each of the antenna elements 5A to 5H. Analog radio frequency signals given to the antenna elements 5A to 5H are radiated from the antenna elements 5A to 5H to the space and transmitted as radio signals.

The digital signal processing unit 8 is configured by a computer including a CPU, a storage unit, and the like. Each functional unit included in the digital signal processing unit 8 described below by reading a program stored in the storage unit and the like is described below. And a function of executing various processes.
The digital signal processing unit 8 performs processing on the transmission side that gives the baseband signal given from the baseband unit 2 to the analog signal processing unit 9 and reception that gives the baseband signal given from the analog signal processing unit 9 to the baseband unit 2 Side processing.

The analog signal processing unit 9 converts the digital baseband signal given from the digital signal processing unit 8 into an analog signal, performs analog signal processing necessary for transmission as a radio signal, and obtains a radio frequency obtained by analog signal processing The signal is given to the antenna element 5.
The analog signal processing unit 9 includes a digital to analog converter (DAC) 11 that converts a digital baseband signal supplied from the digital signal processing unit 8 into analog.
The analog signal processing unit 9 includes an up-converter 12, a power distributor 14, a plurality of variable attenuators 15, a plurality of phase shifters 16, between the digital-analog converter 11 and the antenna element 5. A plurality of power amplifiers (PA) 17 are provided.

The digital-analog converter 11 supplies the baseband signal converted into analog to an up-converter 12 described later.
The up-converter 12 has a function of converting (up-converting) the baseband signal into a radio frequency signal by multiplying the baseband signal by a radio frequency local oscillation signal generated by the oscillator 13. The up-converter 12 passes a radio frequency signal obtained by frequency-converting the baseband signal to the power distributor 14 through an input signal extraction unit 18 described later.
The power distributor 14 distributes the radio frequency signal into a plurality of pieces corresponding to the plurality of antenna elements 5A to 5H.

The variable attenuator 15 is given the radio frequency signal distributed by the power distributor 14. The variable attenuator 15 adjusts the gain for each radio frequency signal distributed by the power distributor 14.
A radio frequency signal whose gain is adjusted by the variable attenuator 15 is given to the phase shifter 16. The plurality of phase shifters 16 individually adjust the phase for each radio frequency signal whose gain is adjusted by each variable attenuator 15. Accordingly, the plurality of phase shifters 16 can control the tilt angle (directivity) of the radio frequency signal transmitted from each of the plurality of antenna elements 5A to 5H.

  The power amplifier 17 has a function of amplifying the power of the radio frequency signal whose phase is adjusted by the phase shifter 16. The power amplifier 17 passes the amplified radio frequency signal to the antenna element 5 through an output signal extraction unit 23 described later. The radio frequency signal given from the power amplifier 17 to the antenna element 5 is radiated from the antenna element 5 to the space and transmitted as a radio signal.

  The variable attenuator 15, the phase shifter 16, and the power amplifier 17 are provided for each of the antenna elements 5A to 5H, and are distributed from the power distributor 14 so as to correspond to each of the antenna elements 5A to 5H. The analog processing necessary for the transmission signal is performed.

<Control configuration of antenna system>
FIG. 3 is a block diagram showing a control configuration of the antenna system 4.
The antenna system 4 includes an input signal extraction unit 18, a reference phase shifter 21, a plurality of output signal extraction units 23, a synthesizer 32, a synthesis level detector 33, a signal extraction unit 34, and an input level detector as main control components. 35 and a control unit 40 are provided.

  The input signal extraction unit 18 has a function of extracting an input signal (radio frequency signal) to each phase shifter 16. The input signal extraction unit 18 in the present embodiment is provided between the up converter 12 and the power distributor 14 (see FIG. 2), and extracts a radio frequency signal that has been frequency converted by the up converter 12. Yes.

  A signal extraction section 34 is further provided in the middle of the first branch line 51 branched from the input signal extraction section 18. The input signal that has passed through the signal extraction unit 34 in the first branch line 51 is applied to the reference phase shifter 21, and the input signal that is extracted from the first branch line 51 by the signal extraction unit 34 is applied to the input level detector 35. .

  The reference phase shifter 21 is provided in the middle of the first branch line 51, and sets the phase of the input signal extracted by the input signal extraction unit 18. The input signal whose phase is set by the reference phase shifter 21 is supplied to the variable attenuator 22, and the gain is adjusted by the variable attenuator 22. The input signal whose gain is adjusted by the variable attenuator 22 is supplied to a synthesizer 32 (described later). A specific phase setting method by the reference phase shifter 21 and a specific gain adjustment method by the variable attenuator 22 will be described later.

An input signal path adjustment unit 19 is provided between the input signal extraction unit 18 and the signal extraction unit 34. The input signal path adjustment unit 19 adjusts the path length from the input signal extraction unit 18 to the synthesizer 32 via the reference phase shifter 21.
Specifically, the input signal path adjustment unit 19 matches the path length so as to match or approximate the input timing of the input signal in the synthesizer 32 and the input timing of the output signal extracted by the output signal extraction unit 23. Is to adjust.

The output signal extraction unit 23 has a function of extracting an output signal (radio frequency signal) output from each phase shifter 16 and input to the corresponding antenna element 5. The plurality of output signal extraction units 23 in the present embodiment are provided in the subsequent stage of each power amplifier 17 and at a position away from the corresponding antenna element 5 by a certain distance.
The second branch line 53 branched from the output signal extraction unit 23 is provided with a switching unit 24 and an output signal path adjustment unit 25 in this order. The switching unit 24 and the output signal path adjusting unit 25 are provided for each antenna element 5.

The switching unit 24 includes, for example, a three-port switch having an a contact, a b contact, and a c contact, and switches the c contact so as to be connected to one of the a contact and the b contact.
The contact c of the switching unit 24 is connected to the output signal extraction unit 23. The contact a of the switching unit 24 is connected to the ground via a resistor 24a and a smoothing capacitor 24b, and the output signal path adjusting unit 25 is connected to the contact b of the switching unit 24.

The output signal path adjustment unit 25 adjusts the path length from each output signal extraction unit 23 via the second branch line 53 to the synthesizer 32.
Specifically, the output signal path adjustment unit 25 is configured so that the difference between the plurality of path lengths from each output signal extraction unit 23 to the synthesizer 32 is an integral multiple of the wavelength of the used frequency. Each path length is adjusted individually.

  A variable attenuator 31 is provided between the output signal path adjustment unit 25 of the second branch line 53 and the combiner 32. The variable attenuator 31 adjusts the gain of the output signal output to the second branch line 53. The output signal whose gain is adjusted by the variable attenuator 31 is supplied to the synthesizer 32.

  When one of the switching units 24 is connected to the b contact, the synthesizer 32 corresponds to the input signal whose phase is set by the reference phase shifter 21 and the switching unit 24 connected to the b contact. The output signal extracted by the output signal extraction unit 23 is synthesized. At the subsequent stage of the synthesizer 32, a synthesis level detector 33 for detecting a synthesis level that is a level of the synthesized signal when the two signals are synthesized by the synthesizer 32 is provided.

  The composite level detector 33 in the present embodiment is formed of, for example, a detection diode, and detects the voltage of the input composite signal as a composite level. In addition to the detector diode, the combined level detector 33 may be another detector as long as it can detect the state of the combined signal, such as a spectrum analyzer. The synthesis level detected by the synthesis level detector 33 is given to the control unit 40.

  The input level detector 35 is provided on the third branch line 57 branched from the signal extraction unit 34 and detects an input level which is the level of the input signal extracted by the signal extraction unit 34. The input level detector 35 in the present embodiment is composed of, for example, a detection diode, and detects the voltage of the input signal that has been input as the input level. Thus, the input level detector 35 can detect the input level of the input signal from the input signal extraction unit 18 to the synthesizer 32. The input level detected by the input level detector 35 is given to the control unit 40.

  As the input level detector 35, other detectors other than the detection diode may be used as long as they can detect the state of the input signal, such as a spectrum analyzer. The signal extraction unit 34 is preferably provided on a path from the input signal path adjustment unit 19 to the variable attenuator 22, and may be provided at an arbitrary position on this path.

Further, the signal extraction unit 34 of the present embodiment is provided on the path through which the input signal flows, but is on the path through which the output signal extracted by the output signal extraction unit 23 flows (for example, variable with the output signal path adjustment unit 25). It may be provided on the path between the attenuator 31 and the attenuator 31. In this case, the output level of the output signal extracted from the signal extraction unit 34 may be detected, and the input level may be acquired by correcting the detected output level.
The antenna system 4 according to the present embodiment includes the signal extraction unit 34 and the input level detector 35. However, when the control unit 40 can grasp the input level of the input signal as digital information, the signal extraction unit 34 is provided. The input level detector 35 may not be provided.

  The control unit 40 is configured by a computer including a CPU and a storage unit 43. The control unit 40 reads out a computer program or the like stored in the storage unit 43 and realizes each functional unit included in the control unit 40 described below. And has a function of executing various processes. The computer program can be stored in a recording medium such as a CD-ROM.

The control unit 40 is connected to the baseband unit 2 and receives control information including a control command for setting a tilt angle of a signal transmitted from the antenna element 5 from the baseband unit 2 and a carrier frequency.
The control unit 40 includes a phase control unit 41 as a functional unit achieved by executing the computer program.

The phase control unit 41 controls the reference phase shifter 21 and the corresponding phase shifter 16 so that the phase of the output signal input to each antenna element 5 becomes a desired phase.
Specifically, the phase control unit 41 controls the reference phase shifter 21 so that the phase of the extracted input signal is opposite to the desired phase. Then, when the phase control unit 41 combines the input signal whose phase is set by the reference phase shifter 21 and the output signal extracted from the output signal extraction unit 23 by the combiner 32, both these signals are The corresponding phase shifters 16 are controlled based on the input level detected by the input level detector 35 and the composite level detected by the composite level detector 33 so as to cancel each other. The phase control unit 41 according to the present embodiment controls the corresponding phase shifter 16 so that the ratio between the input level and the synthesis level is equal to or less than a threshold value.

The phase control unit 41 also individually controls the variable attenuator 15 corresponding to each phase shifter 16, the other variable attenuators 22 and 31, and the switching unit 24. These specific controls will be described later.
In this embodiment, the phase shifter 16, the input signal extraction unit 18, the reference phase shifter 21, the output signal extraction unit 23, the synthesizer 32, the synthesis level detector 33, the input level detector 35, and the control unit 40 are mainly used. A phase control device is configured as a major component.

<Control executed by the control unit>
Next, the control executed by the control unit 40 will be described with reference to FIGS. Here, the control performed at the time of factory shipment of the antenna system 4 will be described.
<Output signal path adjustment confirmation process>
First, at the time of factory shipment, the control unit 40 sets each output signal so that a difference between a plurality of path lengths from each output signal extraction unit 23 to the synthesizer 32 is an integral multiple of the wavelength of the used frequency. It is confirmed whether or not the route adjustment unit 25 is appropriately adjusted.

<Control process of phase shifter corresponding to each antenna element>
When the above-described process of confirming the path adjustment of each output signal is completed, the control unit 40 subsequently shifts the corresponding phase shift so that the phase of the output signal input to the plurality of antenna elements 5A to 5H becomes a desired phase. The device 16 and the like are controlled.
For example, when the control unit 40 (phase control unit 41) receives a control command for setting the phase of the output signal input to the antenna element 5A from the baseband unit 2 to 20 °, first, from the input signal extraction unit 18 The control voltage of the reference phase shifter 21 is controlled so that the phase of the extracted input signal is 200 ° or −160 ° which is the opposite phase to the phase (20 °) of the control command. At that time, the control unit 40 controls the control voltage of the reference phase shifter 21 using the lookup table indicating the relationship between the control voltage value and the phase.

Further, since the passage loss of the input signal by the reference phase shifter 21 changes according to the phase of the control command, the control unit 40 controls the variable attenuator 22 so that the passage loss becomes constant. For example, as shown in FIG. 4, this control can be performed using a look-up table indicating the relationship between each phase and the corresponding gain and pass loss. This lookup table is stored in the storage unit 43.
Here, since the phase of the control command is 20 °, the control unit 40 refers to the look-up table in FIG. 4 so as to cancel the passage loss (−1.5 dB) when the phase is 20 °. The variable attenuator 22 is controlled so that the gain of the input signal is 1.5 dB.

  Next, in FIG. 5, the control unit 40 controls the phase shifter 16 and the variable attenuator 15 disposed on the uppermost side in the figure corresponding to the antenna 5 </ b> A. Specifically, the control unit 40 switches so that the switching unit 24 arranged on the uppermost side in the drawing is connected to the b contact. The other switching units 24 are all connected to the a contact.

As a result, the output signal extracted from the output signal extraction unit 23 arranged at the uppermost position in the drawing is extracted to the second branch line 53, and the switching unit 24, the output signal path adjustment unit 25, and the variable attenuator 31 are connected. Then, it is input to the synthesizer 32.
Therefore, the synthesizer 32 synthesizes the input signal whose phase is set by the reference phase shifter 21 and the output signal extracted from the output signal extraction unit 23 arranged on the uppermost side in the drawing.

  Next, when the input signal input to the combiner 32 and the output signal are combined, the control unit 40 detects the input signal detected by the input level detector 35 so that these two signals cancel each other. The phase shifter 16 arranged on the uppermost side in the figure is controlled so that the ratio between the input level of the signal and the synthesized level of the synthesized signal detected by the synthesized level detector 33 is equal to or less than a preset threshold value. . At this time, since the phase of the output signal is changed by the phase shifter 16, the gain of the output signal passing through the phase shifter 16 is also changed. Therefore, the control unit 40 is arranged in the previous stage of the phase shifter 16. The variable attenuator 15 is also controlled.

  Specifically, the control unit 40 changes the control voltage of the phase shifter 16 and the variable attenuator 15 little by little in order to minimize the ratio between the input level and the composite level, and changes the control voltage. The input level Va detected by the input level detector 35 and the composite level Vs detected by the composite level detector 33 are acquired. Then, the control unit 40 calculates a ratio R (= Va / Vs) between the acquired input level Va and the combined level Vs.

  Next, the control unit 40 determines whether or not the calculated ratio R is reduced to a threshold value or less. When the ratio R is reduced to a threshold value or less, both signals synthesized by the synthesizer 32 have a phase error within a predetermined range (for example, within ± 5 °) and a pass gain error within a predetermined range. This means that the signals have the same magnitude (for example, within ± 0.5 dB), and the two signals cancel each other out of phase.

Therefore, when the determination result is affirmative, the control unit 40 cancels both signals synthesized by the synthesizer 32, so that the phase shifter 16 arranged on the uppermost side in FIG. The control of the attenuator 15 is finished. And the control part 40 switches so that the corresponding switching part 24 may be connected to a contact.
On the other hand, if the determination result is negative, the control unit 40 performs control for changing the control voltage of the phase shifter 16 and the variable attenuator 15 and the determination until the determination result becomes positive. Repeat.

By the above control, the output signal synthesized by the synthesizer 32 is adjusted so as to have an opposite phase to the input signal synthesized with the output signal, that is, in phase with the phase of the control command. As a result, the output signal output from the phase shifter 16 is transmitted from the antenna element 5A with the phase thereof being the phase of the control command (here, 20 °). Therefore, the phase of the signal transmitted from the antenna element 5 during communication can be adjusted to a desired phase.
Moreover, since the control part 40 controls the variable attenuator 15 with the phase shifter 16, it can also adjust the gain of the signal transmitted from the antenna element 5A during communication.

When the control of the phase shifter 16 and the like corresponding to the antenna element 5A is completed as described above, the control unit 40 also sets the phases of the output signals input to the other antenna elements 5B to 5H to desired phases, respectively. As described above, the reference phase shifter 21 and the corresponding phase shifter 16 are sequentially set by the same method as described above.
At that time, if the phase when the output signals extracted from the output signal extraction units 23 corresponding to the antenna elements 5B to 5H are input to the combiner 32 is different, the input signal input to the combiner 32 and The voltage waveform when canceling out the output signal also varies.

  On the other hand, in the present embodiment, the difference between the path lengths corresponding to each of the antenna elements 5A to 5H is adjusted by each output signal path adjustment unit 25 to be a length that is an integral multiple of the wavelength of the operating frequency. Has been. For this reason, when controlling the phase shifter 16 etc. corresponding to each antenna element 5A-5H, the voltage waveform when the input signal input into the combiner 32 and an output signal are canceled can be approximated. Therefore, since the conditions for canceling both signals can be approximated, the phase shifter 16 and the like corresponding to each of the antenna elements 5A to 5H can be easily adjusted.

Further, the output signals that pass through the input signal extraction unit 18 and are extracted by the output signal extraction units 23 pass through the power amplifier 17 and the like provided in the preceding stage of the output signal extraction unit 23, and are thus input to the combiner 32. The input timing of the output signal is later than the input timing of the input signal.
In contrast, in the present embodiment, the path length from the input signal extraction unit 18 to the synthesizer 32 is adjusted so that the input timing of the input signal and the input timing of the output signal in the synthesizer 32 match or approximate. The input signal path adjustment unit 19 is provided in the first branch line 51. For this reason, the input signal path adjustment unit 19 can match or approximate the input timing of the input signal and the input timing of the output signal in the synthesizer 32, so the phase shifters 16 corresponding to the antenna elements 5 </ b> A to 5 </ b> H. Etc. can be adjusted more easily.

  As described above, in the first embodiment, the control unit 40 controls the reference phase shifter 21 so that the phase of the input signal extracted by the input signal extraction unit 18 is opposite to the desired phase. Then, the control unit 40 shifts these signals so as to cancel each other when the combiner 32 combines the input signal having the opposite phase with the output signal extracted by the corresponding output signal extraction unit 23. The phaser 16 is controlled. As a result, the output signal synthesized by the synthesizer 32 is adjusted to have an opposite phase to the input signal synthesized with the output signal, that is, in phase with the desired phase. As a result, the output signal output from each phase shifter 16 has a desired phase and is transmitted from the corresponding antenna element 5. Therefore, the phases of signals transmitted from the plurality of antenna elements 5 during communication can be adjusted to desired phases, respectively.

  Further, when the phase shifter 16 is controlled so as to cancel the two signals, the ratio R between the input level Va of the input signal and the combined level Vs of the combined signal detected by the combined level detector 33 is a threshold value. Since the phase shifter 16 is controlled to be as follows, the phase shifter 16 can be controlled so as to easily cancel both signals even if the value of the input level changes greatly during communication.

  Further, since the input level Va of the input signal extracted from the input signal extraction unit 18 is detected by the input level detector 35, the timing at which the input level Va of the input signal is detected, and the input signal is input to the synthesizer 32. Timing can be approximated. Thereby, the control part 40 can control the phase shifter 16 easily, without considering the delay error between the said both timings.

[Second Embodiment]
FIG. 6 is a block diagram showing a control configuration of the antenna system 4 according to the second embodiment of the present invention. Instead of controlling the phase shifter 16 based on the ratio between the input level and the synthesis level, the antenna system 4 of the present embodiment weights the synthesis level threshold so that the synthesis level is equal to or less than the weighted threshold. It differs from the first embodiment in that the phase shifter 16 is controlled.

The control unit 40 according to the present embodiment includes a phase control unit 41 and a threshold setting unit 44 as functional units achieved by executing a computer program.
The threshold setting unit 44 sets the threshold by weighting the composite level threshold according to the input level detected by the input level detector 35. The threshold setting unit 44 of the present embodiment sets a value obtained by multiplying a predetermined reference value B by a weighting coefficient A as a threshold C, and the input level detected by the input level detector 35 is the input level detector 35. It is determined according to Va.

  For example, the threshold value setting unit 44 determines the weighting coefficient A as a large value when the input level Va is large, and determines the weighting coefficient A as a small value when the input level Va is small. The threshold value setting unit 44 can determine the weighting coefficient A based on an arithmetic expression using the input level Va and a look-up table indicating the relationship between the input level Va and the weighting coefficient A. The threshold C set by the threshold setting unit 44 is given to the phase control unit 41 and the comparator 36.

  The comparator 36 is a component of the antenna system 4 (phase control device) according to the present embodiment, and is arranged at the subsequent stage of the synthesis level detector 33. The comparator 36 receives the composite level threshold C set by the threshold setting unit 44 and the composite level Vs detected by the composite level detector 33. The comparator 36 compares the input threshold value C with the composite level Vs, and outputs either the H level voltage signal or the L level voltage signal based on the comparison result. For example, the comparator 36 of the present embodiment outputs an H level voltage signal when the combined level Vs is equal to or lower than the threshold C, and outputs an L level voltage signal when the combined level Vs exceeds the threshold C. To do. The voltage signal output from the comparator 36 is given to the control unit 40.

In the phase control unit 41 of the present embodiment, when the input signal and the output signal are combined by the combiner 32, the combined level Vs detected by the combined level detector 33 is set so as to cancel out these two signals. The corresponding phase shifter 16 and variable attenuator 15 are controlled so as to be equal to or lower than the threshold C set by the threshold setting unit 44.
Specifically, when the threshold setting unit 44 sets the synthesis level threshold C according to the input level Va detected by the input level detector 35, the phase control unit 41 detects the synthesis detected by the synthesis level detector 33. The control voltages of the phase shifter 16 and the variable attenuator 15 are changed little by little so as to minimize the level Vs. Then, the phase controller 41 compares the combined level Vs detected by the combined level detector 33 when the control voltage is changed with the threshold C set by the threshold setting unit 44 using the comparator 36 ( Voltage signal) is obtained from the comparator 36.

  Next, the phase control unit 41 determines whether or not the voltage signal acquired from the comparator 36 is at the H level, that is, whether or not the combined level Vs is reduced to the threshold value C or less. When the synthesis level Vs is reduced to the threshold value C or less, both signals synthesized by the synthesizer 32 have a phase error within a predetermined range and a pass gain error within the predetermined range. This means that both signals cancel each other out of phase.

Therefore, when the determination result is affirmative, the control unit 40 ends the control of the corresponding phase shifter 16 and variable attenuator 15 because both signals combined by the combiner 32 are canceled. .
On the other hand, if the determination result is negative, the control unit 40 performs control for changing the control voltage of the phase shifter 16 and the variable attenuator 15 and the determination until the determination result becomes positive. Repeat. In addition, the point which abbreviate | omitted description in 2nd Embodiment is the same as that of 1st Embodiment.

  As described above, in the second embodiment, the control unit 40 weights the synthesis level threshold C according to the input level Va, and sets the phase shifter 16 so that the synthesis level Vs is equal to or less than the weighted threshold C. Since the control is performed, even if the input level Va changes greatly, the threshold value C can be set to an appropriate value according to the input level Va. Thereby, the phase shifter 16 can be controlled so as to cancel both the signals easily and reliably.

[Third Embodiment]
FIG. 7 is a block diagram showing a control configuration of the antenna system 4 according to the third embodiment of the present invention. The antenna system 4 of the present embodiment is a modification of the second embodiment, and instead of changing the threshold value according to the input level, the second embodiment is modified in that the composite level is corrected according to the input level. Is different.

  The antenna system 4 of the present embodiment includes an integrator 37 disposed between the synthesis level detector 33 and the comparator 36. The integrator 37 integrates the composite level Vs detected by the composite level detector 33 for a predetermined time, and functions as a correction unit that corrects the composite level Vs. The synthesis level Vs ′ integrated by the integrator 37 is given to the comparator 36.

  The comparator 36 receives the synthesis level threshold C ′ preset by the control unit 40 and the synthesis level Vs ′ integrated by the integrator 37. The comparator 36 compares the input threshold value C ′ with the composite level Vs ′, and outputs one of the H level voltage signal and the L level voltage signal based on the comparison result. For example, the comparator 36 of this embodiment outputs an H level voltage signal when the combined level Vs ′ is equal to or lower than the threshold C ′, and outputs an L level when the combined level Vs ′ exceeds the threshold C ′. Outputs a voltage signal. The voltage signal output from the comparator 36 is given to the control unit 40.

The control unit 40 includes a phase control unit 41 and a correction control unit 45 as functional units achieved by executing the computer program.
The correction control unit 45 controls the integrator 37 so as to change the integration time (cycle) of the integrator 37 according to the input level Va detected by the input level detector 35. For example, the correction control unit 45 shortens the integration time when the input level Va is large, and lengthens the integration time when the input level Va is small.

When the phase controller 41 synthesizes the input signal and the output signal by the synthesizer 32, the synthesis level Vs ′ integrated by the integrator 37 is set to a preset threshold value so as to cancel out these two signals. The corresponding phase shifter 16 and variable attenuator 15 are controlled so as to be equal to or lower than C ′.
Specifically, the correction control unit 45 controls the integrator 37 so as to correct (integrate) the composite level Vs according to the input level Va detected by the input level detector 35, and then the phase control unit 41 The control voltages of the phase shifter 16 and the variable attenuator 15 are changed little by little so that the synthesis level Vs ′ integrated by the integrator 37 is minimized. Then, the phase control unit 41 compares the combined level Vs ′ integrated by the integrator 37 when the control voltage is changed with a preset threshold C ′ by the comparator 36 (voltage signal). Is obtained from the comparator 36.

  Next, the phase control unit 41 determines whether or not the voltage signal acquired from the comparator 36 is at the H level, that is, whether or not the combined level Vs ′ integrated by the integrator 37 is reduced to a threshold value C ′ or less. Determine. When the synthesis level Vs ′ is reduced to the threshold value C ′ or less, both signals synthesized by the synthesizer 32 have the same phase error within the predetermined range and the same gain within the predetermined range. This means that both signals cancel each other out of phase.

Therefore, when the determination result is affirmative, the control unit 40 ends the control of the corresponding phase shifter 16 and variable attenuator 15 because both signals combined by the combiner 32 are canceled. .
On the other hand, if the determination result is negative, the control unit 40 performs control for changing the control voltage of the phase shifter 16 and the variable attenuator 15 and the determination until the determination result becomes positive. Repeat. In addition, the point which abbreviate | omitted description in 3rd Embodiment is the same as that of 2nd Embodiment.

  As described above, in the third embodiment, the control unit 40 controls the integrator 37 so as to change the integration time of the synthesis level Vs in accordance with the input level Va, so that the input level Va changes greatly. Also, the composite level Vs can be corrected to an appropriate value according to the input level Va. Thereby, the phase shifter 16 can be controlled so as to cancel both the signals reliably.

[Fourth Embodiment]
FIG. 8 is a block diagram showing a control configuration of the antenna system 4 according to the fourth embodiment of the present invention. The antenna system 4 of the present embodiment is a modification of the third embodiment, and is different from the third embodiment in that the configuration of a correction unit that corrects the synthesis level is different.

  The antenna system 4 of the present embodiment includes an amplifier 38 disposed between the synthesis level detector 33 and the comparator 36. The amplifier 38 amplifies the synthesis level Vs detected by the synthesis level detector 33, and functions as a correction unit that corrects the synthesis level Vs. The synthesis level Vs ″ amplified by the amplifier 38 is supplied to the comparator 36. The comparator 36 receives the synthesis level threshold C ′ preset by the control unit 40 and the synthesis level Vs ″ amplified by the amplifier 38. Is entered.

  The correction control unit 45 of the control unit 40 controls the amplifier 38 so as to change the gain of the amplifier 38 according to the input level Va detected by the input level detector 35. For example, the correction control unit 45 decreases the gain when the input level Va is large, and increases the gain when the input level Va is small.

When the phase controller 41 combines the input signal and the output signal by the combiner 32, the combined level Vs "amplified by the amplifier 38 is set to a preset threshold value C so as to cancel out these two signals. 'Control the corresponding phase shifter 16 and variable attenuator 15 so that:
Specifically, the correction control unit 45 controls the integrator 37 so as to correct (amplify) the composite level Vs according to the input level Va detected by the input level detector 35, and then the phase control unit 41 The control voltages of the phase shifter 16 and the variable attenuator 15 are changed little by little so as to minimize the composite level Vs ″ amplified by the amplifier 38. Then, the phase control unit 41 changes the control voltage. A result (voltage signal) obtained by comparing the combined level Vs ″ sometimes amplified by the amplifier 38 with a preset threshold C ′ by the comparator 36 is obtained from the comparator 36.

  Next, the phase control unit 41 determines whether or not the voltage signal acquired from the comparator 36 is at the H level, that is, whether or not the combined level Vs ″ amplified by the amplifier 38 is reduced to a threshold value C ′ or less. When the synthesis level Vs ″ is reduced to the threshold value C ′ or less, both signals synthesized by the synthesizer 32 have a phase error within a predetermined range and a pass gain error within a predetermined range. Means that both signals are canceled out of phase with each other.

Therefore, when the determination result is affirmative, the control unit 40 ends the control of the corresponding phase shifter 16 and variable attenuator 15 because both signals combined by the combiner 32 are canceled. .
On the other hand, if the determination result is negative, the control unit 40 performs control for changing the control voltage of the phase shifter 16 and the variable attenuator 15 and the determination until the determination result becomes positive. Repeat. In addition, the point which abbreviate | omitted description in 4th Embodiment is the same as that of 3rd Embodiment.

  As described above, in the fourth embodiment, the control unit 40 controls the amplifier 38 so as to change the gain of the amplifier 38 that amplifies the combined level Vs in accordance with the input level Va. Therefore, the input level Va is increased. Even if it changes, the composite level Vs can be corrected to an appropriate value in accordance with the input level Va. Thereby, the phase shifter 16 can be controlled so as to cancel both the signals reliably.

[Others]
The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the meanings described above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims. For example, the array antenna system 4 of the above embodiment can be applied to antenna systems other than the active antenna system. Moreover, the phase control apparatus of the said embodiment is applicable also to communication systems other than an antenna system.

DESCRIPTION OF SYMBOLS 1 Base station apparatus 2 Baseband unit 3 Signal transmission path 4 Active antenna system (array antenna system)
5 antenna element 8 digital signal processing unit 9 analog signal processing unit 11 digital analog converter 12 up converter 13 oscillator 14 power distributor 15 variable attenuator 16 phase shifter 17 power amplifier 18 input signal extraction unit 19 input signal path adjustment unit 21 Reference phase shifter 22 Variable attenuator 23 Output signal extraction unit 24 Switching unit 24a Resistor 24b Capacitor 25 Output signal path adjustment unit 31 Variable attenuator 32 Synthesizer 33 Synthesis level detector 34 Signal extraction unit 35 Input level detector 36 Comparator 37 Integrator (correction unit)
38 Amplifier (correction unit)
40 control unit 41 phase control unit 43 storage unit 44 threshold setting unit 45 correction control unit 51 first branch line 53 second branch line 57 third branch line A weighting coefficient B reference value C threshold R ratio Va input level Vs composite level

Claims (8)

A phase control device having a phase shifter for adjusting the phase of a signal,
An input signal extraction unit for extracting an input signal to the phase shifter;
A reference phase shifter for setting the phase of the extracted input signal;
An output signal extraction unit for extracting an output signal output from the phase shifter;
A synthesizer that synthesizes the input signal whose phase is set by the reference phase shifter and the extracted output signal;
A synthesis level detector for detecting a synthesis level which is a level of a synthesized signal of the synthesizer;
A control unit that controls the reference phase shifter and the phase shifter so that the phase of the output signal becomes a desired phase;
The control unit controls the reference phase shifter so that the phase of the extracted input signal is opposite to the desired phase, and combines the input signal and the output signal having the opposite phase by the combiner. A phase control device for controlling the phase shifter based on the input level which is the level of the input signal and the composite level detected by the composite level detector so as to cancel out both of these signals. .   The phase control apparatus according to claim 1, further comprising an input level detector that detects an input level of the extracted input signal.   The phase control apparatus according to claim 1, wherein the control unit controls the phase shifter so that a ratio between the input level and the combined level is equal to or less than a threshold value.   The control unit according to claim 1 or 2, wherein the control unit weights a threshold value of the synthesis level according to the input level, and controls the phase shifter so that the synthesis level is equal to or less than the threshold value after the weighting. The phase control device described. A correction unit for correcting the composite level;
3. The phase according to claim 1, wherein the control unit controls the correction unit according to the input level, and controls the phase shifter so that the corrected combined level is equal to or less than a threshold value. Control device. The correction unit is an integrator that integrates the composite level,
The phase control device according to claim 5, wherein the control unit controls the integrator so as to change an integration time of the integrator according to the input level. The correction unit is an amplifier that amplifies the synthesis level,
The phase control device according to claim 5, wherein the control unit controls the amplifier so as to change a gain of the amplifier according to the input level. A plurality of antenna elements;
A plurality of phase shifters that individually adjust the phase of the signals transmitted by each of these antenna elements;
An input signal extraction unit for extracting input signals to the plurality of phase shifters;
A reference phase shifter for setting the phase of the extracted input signal;
A plurality of output signal extraction units for outputting output signals output from the respective phase shifters and input to the corresponding antenna elements;
A synthesizer that synthesizes the input signal whose phase is set by the reference phase shifter and the extracted output signal;
A synthesis level detector for detecting a synthesis level which is a level of a synthesized signal of the synthesizer;
A control unit that controls the reference phase shifter and the corresponding phase shifter so that the phase of the output signal input to the antenna element becomes a desired phase;
The control unit controls the reference phase shifter so that the phase of the extracted input signal is opposite to the desired phase, and combines the input signal and the output signal having the opposite phase by the combiner. An array antenna system for controlling the phase shifter based on an input level which is a level of the input signal and the composite level detected by the composite level detector so as to cancel both of these signals. .

Images