JP4049118B2 - Waveguide switch and waveguide switching method - Google Patents

Description

  The present invention relates to a waveguide switch for switching the connection between an input-side waveguide and an output-side waveguide, and a waveguide switching method.

  When performing an electrical characteristic test on a wireless device having a plurality of reception channels, a waveguide switch is used to individually input a test signal corresponding to each reception channel. This waveguide switch outputs the input test signal to a specific reception channel by switching the waveguide. As the number of receive channels increases, the waveguide switch must have more output ports.

  As a conventional waveguide switch, an input interface unit having an input port for inputting a high-frequency signal, an output interface unit having an output port for outputting a high-frequency signal, a linear interface between the input interface unit and the output interface unit A device including a movement switching unit arranged to be movable along the axis of the guide is known (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2003-332803 (refer to page 1 and page 2 and FIG. 4)

In a conventional waveguide switch, the movement switching unit has as many waveguides as the number of output ports, and each waveguide transmits a high-frequency signal to an individual output port. The input interface unit and the output interface unit are fixed to the support mechanism. An index plate in which a plurality of depressions are formed at the same pitch along the axis of the linear guide is fixed to the support mechanism. A plunger is fixed to the movement switching unit.
When the movement switching unit moves along the axis of the linear guide, the plunger also moves while causing the protrusion to elastically contact the recess of the index plate. Each time the protruding portion of the plunger falls into the depression, the movement switching portion is held at that position, and the input port of the waveguide is connected to any one of the output ports of the waveguide.
As a result, the reception channel can be easily switched, and the electrical characteristic test can be performed efficiently.

However, in the conventional waveguide switch, there is a limit to the positioning accuracy between the plunger and the depression, and there is a difference in the loss of the propagation signal for each channel of the output port.
Further, once the positions of the plunger and the recessed portion are fixed, it is difficult to readjust the fixing positions of both. If the installation position of the input interface section and output interface section shifts due to long-term use, a large loss occurs in the propagation signal of the waveguide switch, giving an unexpected error to the test system of the electrical characteristics test, and the correct test A situation that the characteristics could not be obtained occurred. Further, when a large number of waveguide switches are connected and used, there is a problem that it takes a lot of time to identify which waveguide switch has a loss.
Therefore, there is a problem that the measurement quality of the electrical characteristic test of the wireless device is deteriorated by using the waveguide switch.

  The present invention has been made in view of the above, and an object of the present invention is to accurately switch the connection of a waveguide switch and to reduce deterioration in measurement quality during an electrical characteristic test of a wireless device.

  The present invention has been made to solve the above-described problems, and is sandwiched between an input interface having a waveguide, an output interface having a plurality of waveguides, and the input interface and the output interface. And a movement switching unit having a plurality of waveguides respectively connecting the waveguide of the input interface and at least one waveguide of the output interface, and driving for linearly moving the movement switching unit , A position detection unit that detects a movement position of the movement switching unit, a power monitor that measures an output signal output from a part of the waveguide of the output interface, and an output signal that is measured by the power monitor The position reference of the movement switching unit is set so that the power of the signal becomes the optimum level, and the difference between the set position reference and the movement position detected by the position detection unit is set. Zui it, in which a control section for position control movement switching unit.

  As described above, according to the present invention, the waveguide switch can be accurately positioned, and the loss of the propagation signal of the test system accompanying the switching of the connection of the waveguide switch can be reduced.

  Embodiments of a waveguide switch according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
The waveguide switch according to this embodiment uses a millimeter wave band radio wave to obtain a beat frequency from a difference between a reception wave and a transmission wave in which the radio wave radiated forward bounces off the preceding vehicle, It is suitably applied to the performance test of FM-CW radar that calculates the distance to the target and the relative velocity using the beat frequency.

  In the FM-CW radar, when a transmission wave whose frequency is modulated in a triangular wave shape is transmitted toward a target and the transmission frequency changes linearly, a stable beat signal having one frequency can be obtained. . However, if the transmission frequency is not an accurate straight line and ripple noise is superimposed, another peak (spurious) appears in the beat signal at a position shifted from the peak frequency by a frequency according to the period of the ripple noise. Such spurious becomes a big obstacle in accurately calculating the distance and speed of the target and affects the target detection performance.

  As the target detection performance of the FM-CW radar, it is required that the target spectrum width is narrow and spurious is not generated at an extra frequency. A radar performance test is performed to confirm the target detection performance. In this radar performance test, a target simulator is used in which a delay line corresponding to the test distance is connected to the transmission signal output from the radar transmitter to add a time delay and return the signal to the radar receiver.

  Next, details of the FM-CW radar will be described. FIG. 1 is a diagram showing a system configuration of an FM-CW radar. FIG. 2 is a diagram showing the configuration of the radar signal processor.

As shown in FIG. 1, the FM-CW radar 20 includes a transmitter 51, a receiver 52, a waveguide interface 56, a transmission antenna 4, a reception antenna 5, and a radar signal processor 500. .
The transmitter 51 includes a modulation circuit 1, a D / A converter 8, a voltage controlled oscillator (VCO; hereinafter referred to as an oscillator) 2, a directional coupler 3, and a high output amplifier 53. The receiver 52 includes a receiver 7, a mixer 6, and a video amplifier 54.
The transmitter 51, the receiver 52, and the waveguide interface 56 constitute a transmission / reception module 55. The high-power amplifier 53 is connected to the transmission waveguide terminal 21 of the waveguide interface 56, and the receiver 7 is connected to the reception waveguide terminals (22, 23, 24) of the waveguide interface 56. . The receiver 7 includes a plurality of reception channels, and includes a plurality of low noise amplifiers corresponding to the respective reception channels, a power combiner that combines output signals of the respective low noise amplifiers, and the like (not shown). For example, refer to Japanese Patent Application Laid-Open No. 2002-76241 for details.) In the example of FIG. 1, the receiver 7 has three reception channels.

  The transmission antenna 4 and the reception antenna 5 are connected to the transmission waveguide terminal 21 and the reception waveguide terminal (22, 23, 24) of the waveguide interface 56, respectively. The waveguide interface 56 is formed with a predetermined number of waveguides penetrating both surfaces of the metal plate, and functions as an interface for connecting the waveguides on one side and the other side.

  The receiving antenna 5 is composed of a plurality of receiving antennas that form a multi-beam. The waveguide interface 56 is provided with a plurality of reception signal waveguides corresponding to the respective reception antennas. In the example of the figure, the receiving antenna 5 is composed of three antennas, and there are three receiving channels. The antenna elements of the transmission antenna 4 and the reception antenna 5 are each composed of a plurality of radiation conductors.

  As shown in FIG. 2, the radar signal processor 500 includes an A / D converter 60, a frequency analyzer 9, a target detector 10, and a distance / speed calculator 11.

Next, the operation of the FM-CW radar 20 will be described.
The radar signal processor 500 outputs a modulation control signal that controls the operation of the modulation circuit 1. When a control signal is input from the radar signal processor 500, the modulation circuit 1 generates a discretized digital frequency modulation (FM) signal at a preset variable timing. The digital frequency modulation (FM) signal is converted into a control voltage signal by the D / A converter 8, and the converted control voltage signal is sent to the oscillator 2. The oscillator 2 generates a high frequency signal modulated with the FM signal based on the control voltage signal, and sends the high frequency signal to the high output amplifier 53 via the directional coupler 3. The high output amplifier 53 amplifies the high frequency signal, and the amplified signal is fed from the transmission waveguide terminal 21 of the waveguide interface 56 to the transmission antenna 4. The high frequency signal generated by the oscillator 2 is sent to the mixer 6 via the directional coupler 3.

The transmission antenna 4 emits the transmitted high frequency signal as a transmission wave to a target ahead. When the target is present, a reception wave (reflected wave) having a time delay is received by the reception antenna 5. The receiving antenna 5 forms three multi-beams by three receiving channels. A reception signal of the reception antenna 5 is input to a plurality of reception waveguide terminals of the waveguide interface 56. In the illustrated example, the signals are input to the three reception waveguide terminals 22, 23, 24 corresponding to the three reception channels of the reception antenna 5. Signals input to the receiving waveguide terminals 22, 23, 24 are subjected to low noise amplification, power combining, and the like in the receiver 7, and are sent to the mixer 6.
The mixer 6 generates a beat signal having a frequency difference between the reflected wave and the transmission wave distributed by the directional coupler 3 and sends the beat signal to the video amplifier 54. The video amplifier 54 amplifies the beat signal and inputs it to the radar signal processor 500 as an analog video signal.

  The radar signal processor 500 converts the video signal including the input beat signal into a digital signal by the A / D converter 60 and sends the digital signal to the frequency analyzer 9. The frequency analyzer 9 takes in the digitized beat signal and obtains a frequency distribution (frequency spectrum) by processing such as FFT (Fast Fourier Transform). The target detector 10 compares the frequency distribution with the threshold value, and sets a target that is maximum among those exceeding the threshold value. The distance / speed calculator 11 calculates the relative distance and relative speed of the target based on the frequency picked up by the target detector 10. Further, the target detector 10 multiplies the digital video signal by a weighting function of the beam direction to form a multi-beam, and performs angle measurement processing on the formed multi-beam to calculate the target presence direction.

  FIG. 3 shows the relationship between the transmission wave SD and the reception wave ZD. In the up-chirp section, the frequency of the transmission wave SD is linearly increased, and in the down-chirp section, the frequency of the transmission wave SD is linearly decreased.

When the target is present at a relative speed V and a relative distance R with respect to the FM-CW radar 20, the speed of light is C, the transmission wavelength is λ, the period of the up-chirp section (or down-chirp section) is Tm, and frequency modulation is performed. If the width is Δf,
The Doppler frequency fd corresponding to the relative speed is expressed by the following equation (1):
fd = 2 · V / λ (1)
And
The distance frequency fr generated by the time difference between the transmission frequency and the reception frequency is expressed by the following equation (2):
fr = (2R · Δf) / (C · Tm) (2)
And
The beat frequency fb1 in the up chirp section and the beat frequency fb2 in the DOWN chirp section are as shown in the following equations (3) and (4):
fb1 = | fd−fr | (3)
fb2 = | fd + fr | (4)
And
Further, when the distance frequency fr is larger than the Doppler frequency fd, the following expression (5) is established.
2fr = fb1 + fb2 (5)
By substituting equation (2) into equation (5), equation (6) for obtaining the relative distance R from the FM-CW radar to the target is derived.
R = (C · Tm) / (4 · Δf) (fb1 + fb2) (6)

  And the distance R to a target is calculated | required by using Formula (6). Further, when the distance frequency fr is calculated, the relative speed V can also be obtained from the equations (1), (3), and (4).

  4A to 4C are diagrams illustrating frequency spectra of beat signals of the FM-CW radar. When the transmission frequency changes linearly, the beat signal stably becomes one frequency, the peak value appears sharply as shown in the frequency spectrum of FIG. 4A, and the surroundings are side lobes according to the window function. Become a level. However, when the transmission frequency is not an accurate linear shape and ripple noise is superimposed, another peak (spurious) appears at a position shifted from the peak frequency by a frequency according to the period of the ripple noise. FIG. 4B shows a case where the frequency of the ripple noise is close to the spectral resolution, and spurious is generated in the middle of the spectrum of the beat signal. In FIG. 4C, a spurious signal having a large ripple frequency and completely separated from the spectrum of the beat signal is generated. As described above, such spurious is a big obstacle in accurately calculating the distance and speed of the target. Therefore, it is necessary to perform a target detection performance test to inspect for the occurrence of spurious.

Next, a radar test apparatus according to the present invention will be described. The radar test apparatus described here performs test evaluation of the target detection performance of the transmission / reception module 55 among the configurations of the FM-CW radar 20 that is the test target. Although the radar test apparatus has other test functions, the description of the other test functions and their configurations is omitted here.
FIG. 5 is a diagram showing a configuration of the radar test apparatus 100.
In the figure, the radar test apparatus 100 includes a controller 40, a frequency analyzer 50, a waveguide switch 70, and a signal input device 71.

The controller 40 includes a personal computer having a CPU, ROM, RAM, hard disk, display unit, input unit, and the like, a dedicated computer, and the like, and operates an application program stored in a memory such as a ROM or a hard disk. The controller 40 controls the display of screens corresponding to various tests and the control of test equipment such as the frequency analyzer 50, the waveguide switch 70, and the signal input device 71 based on the operation control of the CPU according to the execution instruction of the application program. I do. The input unit uses a mouse, keyboard, etc., so that various selection information corresponding to the execution processing of the application program can be input by selecting a selection button on the screen of the display unit by operating the input unit. It is made.
The controller 40 is connected to the modulation circuit 1 of the transmission / reception module 55, and sends a modulation control signal to the modulation circuit 1 to control the transmission operation of the transmission / reception module 55.

The waveguide switch 70 switches the connection between the signal input device 71, the reception waveguide terminals 22, 23 and 24 (three reception channels) and the power meter 72 of the transmission / reception module 55. The waveguide switch 70 has a moving stage (linear stage) that moves linearly by driving a stepping motor.
The waveguide switch 70 has one input port Ri on the input side and four output ports R1, R2, R3, and Ro on the output side. The input port Ri is connected to the output terminal of the signal input device 71. The three output ports R1, R2, and R3 are connected to the receiving waveguide terminals 22, 23, and 24, respectively. The output port Ro is connected to the power meter 72. The output port Ro may further include two ports Ro1 and Ro2.

  Based on the preset switching information of the output port of the waveguide switch 70 (for example, information for instructing to connect the input port Ri of the waveguide switch to the output port R1), the controller 40 A drive signal for switching the connection of the waveguide switch 70 is transmitted. When the waveguide switch 70 receives a linear stage drive signal from the controller 40, the waveguide switch 70 drives the linear stage to switch the connection of the switch. At this time, the controller 40 controls switch connection switching so that the input port Ri is connected to any one of the output ports R1, R2, R3, and Ro. Details of the configuration and switching operation of the waveguide switch 70 will be described later.

FIG. 6 is a diagram showing the configuration of the signal input device 71.
The signal input device 71 includes a delay line 80, a coupler 81, a variable attenuator 82, and a power meter 83. The delay line 80 delays the transmission signal output from the transmission waveguide terminal 21 of the waveguide interface 56 by an electrical length corresponding to a propagation length in air of 100 m to 200 m. The obtained delayed signal passes through the coupler 81 and is output to the variable attenuator 82. The variable attenuator 82 changes the amount of attenuation according to the signal input device control signal from the controller 40. Further, the attenuation signal is input to the input port Ri of the waveguide switch 70. The power meter 83 measures the power level of the passing signal of the delay line 80 branched by the coupler 81. The measured power level is output to the controller 40 and recorded.

  The frequency analyzer 50 has a frequency sweep function and operates as a spectrum analyzer. The frequency analyzer 50 performs frequency analysis processing by FFT on the video signal output from the video amplifier 54 of the transmission / reception module 55, and sends the analysis processing result to the controller 40. The controller 40 obtains the target spectrum based on the frequency analysis processing result from the frequency analyzer 50, and evaluates the spectrum width, the presence / absence of spurious, etc. from the obtained target spectrum.

FIG. 7 is an example of a standard for performing pass / fail judgment of a target spectrum by the controller 40, and the curve in the figure qualitatively shows an example of the target spectrum of the transmission / reception module 55. In the range where the gain of the target spectrum is larger than the gain B ₀ , the deviation from the center frequency f ₀ is set within the predetermined range A [kHz] and exceeds the predetermined range A [kHz] from the center frequency f ₀ . In the region, if the gain of the target spectrum is smaller than the gain B ₀ , the result is acceptable. Those outside this range are judged as rejected.

  Of course, when the test evaluation of the transmission characteristics of the transmission / reception module 55 in such an up-chirp period is completed, the time-frequency data in the down-chirp period measured by the frequency analyzer 50 is used in the down-chirp period. The test evaluation of the transmission characteristics of the transmission / reception module 55 may be executed.

  When performing the target detection performance test, the reception channel of the receiver 7 in the transmission / reception module 55 is designated and the performance test is performed. In this case, if there is a difference in gain or linearity of the low noise amplifier for each designated reception channel, a difference occurs in the beat signal output from the video amplifier 54 between the reception channels. This disparity affects the angle measurement performance of the radar signal processor and degrades the angle measurement performance. Therefore, it is necessary to grasp the degree of performance disparity between receiving channels (for example, gain characteristics) and the presence / absence of performance disparity (for example, whether there is reception spurious for each receiving channel) through radar performance tests. .

In the radar performance test according to this embodiment, the connection of the waveguide switch 70 is switched under the control of the controller 40 during the target detection performance test. When the waveguide switch 70 receives the connection switching signal, the waveguide switch 70 connects the signal input device 71 to the reception waveguide terminals 22, 23 and 24 (three reception channels) of the transmission / reception module 55 and the power meter 72. Switch automatically.
As a result, the reception channel can be switched, and the performance test of the output beat signal can be performed corresponding to each switched reception channel. As a result of the test, if there is a performance difference between the reception channels, the amplification factor of the amplifier and the resistance value of the variable resistor for setting the control parameter are adjusted so as to correct the difference between the reception channels. Alternatively, when the performance gap is larger than the allowable range, the single transceiver module 55 may be rejected.

  In the above-described example, the example in which the test is performed by switching the reception channel during the target detection performance test has been described. However, the present invention is not necessarily limited to this. For example, only the functional test of the receiver 52 may be performed without connecting the delay line 80 before performing the target detection performance test. In this case, the input / output characteristics (linearity) of the receiver, the band characteristics of the receiver gain, the noise characteristics of the receiver, and the like are tested, and the characteristics of each reception channel are evaluated. As a result, the characteristic disparity between channels can be tested in advance, so that the target detection performance test need only be performed for a specific channel.

  As described above, the target detection performance (transmission characteristics) of the transmission / reception module 55 constituting the FM-CW radar 20 can be tested and evaluated.

Next, the configuration of the waveguide switch 70 will be described in detail.
8A and 8B are configuration diagrams showing the waveguide switch 70. FIG. 8A is a side view, FIG. 8B is a cross-sectional view taken along the line I-I, and FIG. FIG. 8D is a diagram showing a connection example between the waveguide interface 56 and the waveguide switch.

In the figure, the waveguide switch 70 includes an input interface 91, an output interface 92, a movement switching plate 93, a linear stage 96, a support plate 94, and a pedestal 95.
The input interfaces 91 and 92 and the movement switching plate 93 are formed in a plate shape by a metal member such as aluminum or stainless steel. The input interfaces 91 and 92 are fixed to a pair of support plates 94, respectively. The support plate 94 is fixed to the pedestal 95. The input interfaces 91 and 92 and the support plates 94 are positioned and fixed by pins 98. Each support plate 94 and pedestal 95 are positioned and fixed by pins 99. The movement switching plate 93 is disposed between the input interfaces 91 and 92. One side of the movement switching plate 93 faces the input interface 91, and the other side of the movement switching plate 93 faces the output interface 92. The gap between the waveguide interface 90 and the waveguide plate 91 and the gap between the output interface 92 and the waveguide plate 91 are each 0.1 mm or less.
The length of the side surface of the movement switching plate 93 is about 150 mm, the width is about 50 mm, and the arrangement pitch of the waveguides is about 14 mm on the input interface 91 side and about 7 mm on the output interface 92 side. The waveguide has a rectangular cross section of 2.5 mm × 1.25 mm.

The linear stage 96 includes a linear guide (not shown) and a driving device 101, and constitutes a stepping motor driving precision stage. The drive device 101 includes a motor control circuit including a stepping motor, a speed reducer, a precision ball screw, and a power amplifier (not shown). Above the linear stage 96, a movable portion 97 of the linear guide protrudes.
The linear stage 96 is sandwiched between a pair of support plates 94 and fixed to the upper surface of the pedestal 95. The linear stage 96 can move the movable portion 97 straight back and forth along the axis of the linear guide. That is, the movable portion 97 is linearly driven back and forth in parallel with the upper surface of the pedestal 95. The positioning accuracy of the stepping motor driven precision stage is about 0.5 μm or less. Preferably it is 0.3 μm or less. The lower surface of the movement switching plate 93 is fixed to the upper portion of the movable portion 97.

The input interface 91, the output interface 92, and the movement switching plate 93 are each provided with a waveguide.
The input interface 91 has one waveguide 135 that forms the input port Ri and penetrates the front and back surfaces, and a through hole 130 filled with a radio wave absorber. A choke is provided around the waveguide 135 and the through hole 130 of the input interface 91. Thereby, leakage of radio waves from the gap between the movement switching plate 93 and the input interface 91 is prevented.
The waveguide 135 is disposed between the two through holes 130 on both sides, and the arrangement pitch between the adjacent through holes 130 and between the through holes 130 and the waveguide 135 is equal.

  The output interface 92 includes output waveguides R1, R2, R3, Ro1, and Ro2, and includes five waveguides 136 penetrating the front and back. Each waveguide 136 is arranged in parallel with each other. A choke is provided around the waveguide 136 of the output interface 92. Thereby, leakage of radio waves from the gap between the movement switching plate 93 and the output interface 92 is prevented. In the illustrated example, the output ports are arranged in the order of Ro2, R1, R2, R3, and Ro1 from the right.

  In the movement switching plate 93, a plurality of waveguides penetrating from one end surface to the other end surface are bent or linearly provided. In the illustrated example, there are five waveguides K1 to K5. In the vicinity of one side surface of the movement switching plate 93, the waveguide arrangement pitch hp is equal to the arrangement pitch of the adjacent through holes 130 and the waveguide 135 of the output interface 92. Near the other side surface of the movement switching plate 93, the waveguides 136 are arranged at a pitch twice the arrangement pitch hp of the through holes 130 and the waveguides 135 near one side surface of the movement switching plate 93. On the other side of the movement switching plate 93 that faces the output interface 92, a retaining hole 132 in which a waveguide wave absorber is embedded is provided between the adjacent waveguide 136. When the movement switching plate 93 is moved so that the tube axes of the waveguides K1 to K5 are opposed to each other so as to coincide with the tube axes of the waveguide 136, the blind hole 132 is formed in any one of the waveguides 136. The position is set so that the tube axis and the tube axis coincide with each other.

  As shown in FIG. 8D, the output ports R1, R2, and R3 of the output interface 92 are connected to the receiving waveguide terminals 22 and 23 of the waveguide interface 56 with the connecting waveguide 140 interposed therebetween. 24 are switched and connected.

Next, the switch switching operation of the waveguide switch 70 will be described.
The movement switching plate 93 can switch the waveguide connection between the input interface 91 and the output interface 92 in five states by moving in the front-rear direction along the axis of the linear guide.
FIG. 9 is a diagram illustrating a switching connection state of the waveguide switch 70. A connection example between the input interfaces 91 and 92 and the movement switching plate 93 in each state will be described with reference to FIG.

FIG. 9A shows a first state in which the movement switching plate 93 is moved in the forward direction. In the figure, the input port Ri is connected to the waveguide K2, and the waveguide K2 is connected to the output port R1. As a result, the input port Ri is connected to the output port R1.
In this state, the output signal of the signal input device 71 is input to the reception waveguide terminal 22 of the waveguide interface 56.

FIG. 9B shows a second state in which the movement switching plate 93 is moved to the center position. Here, the input port Ri is connected to the waveguide K3, and the waveguide K3 is connected to the output port R2. As a result, the input port Ri is connected to the output port R2.
In this state, the output signal of the signal input device 71 is input to the reception waveguide terminal 23 of the waveguide interface 56.

FIG. 9C shows a third state in which the movement switching plate 93 is moved backward. Here, the input port Ri is connected to the waveguide K4, and the waveguide K4 is connected to the output port R3. As a result, the input port Ri is connected to the output port R3.
In this state, the output signal of the signal input device 71 is input to the reception waveguide terminal 24 of the waveguide interface 56.

  FIG. 9D shows a fourth state in which the movement switching plate 93 is further moved backward. Here, the input port Ri is connected to the waveguide K5, and the waveguide K5 is connected to the output port Ro1. As a result, the input port Ri is connected to the output port Ro1.

FIG. 9E shows a fifth state in which the movement switching plate 93 has been moved forward again. Here, the input port Ri is connected to the waveguide K1, and the waveguide K1 is connected to the output port Ro2. As a result, the input port Ri is connected to the output port Ro2.
The waveguide switch 70 can switch the connection state of the waveguides in this way, and functions as a waveguide connection changeover switch.

Next, switching control of the waveguide switch 70 will be described.
FIG. 10 is a diagram showing the configuration of the control system of the waveguide switch.
In the figure, the waveguide switch control system includes a waveguide switch 70, a driving device 101, a power meter 72 (72a, 72b), a signal input device 71, a position detector 110, and a coordinate database 112. And the controller 40.

The drive device 101 drives the stepping motor while adjusting the phase current and power supply current of the stepping motor based on the control command including the rotation angle command from the controller 40. Thereby, the movement switching plate 93 of the waveguide switch 70 is moved along the axis of the linear guide. The stepping motor may be movable in full steps, but since the positional accuracy required for the movement switching plate 93 is 0.5 μm or less, microstep driving (for example, 1/2 microstep driving) is performed to increase the angular resolution. Is preferred.
The power meters 72a and 72b measure the power levels of the output signals of the output ports Ro1 and Ro2 of the waveguide switch 70, respectively.

  The input signal of the signal input device 71 is attenuated by the variable attenuator 82 and is input to the waveguide switch 70 and is input to the power meter 83 to measure the power level of the input signal. The variable attenuator 82 sets the attenuation rate to a desired value based on the setting signal from the controller 40. Needless to say, when the delay line 80 is connected, a constant phase difference can be added to the output signal from the variable attenuator 82.

  The position detector 110 detects the movement position of the movement switching plate 93 of the waveguide switch 70. Here, the moving position indicates the position coordinates of the movable portion 97 (that is, the movement switching plate 93) relative to the fixed portion (not shown) of the linear stage when the movable portion 97 moves along the axis of the linear guide. The absolute position coordinates set on the linear stage are detected.

  The coordinate database 112 stores a coordinate table (a coordinate table 115 described later in FIG. 12) associated with each output port Rj (j = o1, 1, 2, 3, o2). The coordinate table includes output port identification information, optimum position coordinate information corresponding to the output port, and relative position coordinate difference information. As output port identification information, an output port name or an arbitrarily set port number is used. The optimum position coordinate information indicates the coordinate data (optimum position coordinates) of the movement position respectively output from the position detector 110 when the output power of each output port is maximized. The relative position coordinate difference information indicates a difference in optimum position coordinates between each output port Rj and output port Ro1.

The controller 40 sets a control command to be supplied to the driving device 101 based on the detection signals of the power meters 72a and 72b, the detection signal of the position detector 110, and the setting information of the coordinate table of the coordinate database 112, and drives The apparatus 101 is controlled. In particular, position control is performed so that the output power of the output port Ro1 is maximized.
The controller 40 sets the attenuation rate according to the power level of the power meter 83 so that the power of the output signal from the variable attenuator 82 is constant without depending on the individual difference of the input signal, and the setting signal is variable. Send to attenuator 82.

  Note that the device under test 55 here is a transmission / reception module 55. The input signal is a signal obtained by delaying the transmission wave T <b> 1 output from the transmission waveguide terminal 21 of the waveguide interface 56 in the transmission / reception module 55 through the delay line 80. Of course, when testing the characteristics of the receiver 7 alone, the delay line 80 may not be provided.

Next, the operation of the waveguide switch control system will be described.
In the waveguide switch 70, since the relative positions between the output ports are mechanically fixed, the relative positions between the ports do not shift in the short term. When switching control of the waveguide switch 70 is performed, there is a method of performing position control by setting the absolute position coordinate of the output port as a target position. However, since the waveguide switch 70 uses the linear stage 96, the drive system of the precision ball screw backlash of the linear stage, the bearing clearance of the linear guide, or the like between the movement switching plate 93 and the output interface 91. The absolute position always changes due to a position shift or a position shift accompanying a temperature change. For this reason, in this embodiment, control is performed using the power of each output port, not the absolute position.

FIG. 11 is a diagram showing an operation flow of the control system.
First, in steps S101, S102, and S103, the waveguide switch is pre-adjusted.
In step S101, coordinate data corresponding to each output port is measured and set.
First, all output ports (R1, R2, R3, Ro1, Ro2) are connected to a waveguide for test adjustment, and output ports Rj (hereinafter, j = 1, 2, 3, o1, o2) to be measured are connected. An adjustment power meter is connected to the connected test adjustment waveguide. A signal generator (not shown) is connected as an input signal of the signal input device 71. For example, a signal generator that outputs a high-frequency signal for testing at a desired frequency is used.
Next, the movement switching plate 93 is manually moved to a position where the power of the output port Rj to be measured becomes maximum. At this time, the position coordinate value xj detected by the position detector 110 is set as the optimum position coordinate Xj corresponding to the output port to be measured. The optimum position coordinate Xj is stored in a coordinate table corresponding to the output port Rj of the coordinate database 112. The output ports Rj to be measured are sequentially changed, set as the optimum position coordinates Xj for each output port Rj, and stored in the coordinate table as optimum position coordinate information associated with each output port Rj. Further, the output port Ro1 is set as a reference output port.
Next, after the optimum position coordinate Xj associated with each output port Rj is set, a difference value (Yj = Xj) between the optimum position coordinate Xj of each output port Rj and the optimum position coordinate Xo1 of the reference output port Ro1. -Xo1) is calculated for each output port Rj. The calculated difference value Yj is stored in the coordinate table as relative position coordinate difference information in association with the output port Rj.

FIG. 12 is a diagram illustrating an example of the coordinate table 115 stored in the coordinate database 112.
In the figure, the coordinate table 115 stores the names of the output ports (Ro2, R1, R2, R3, Ro1 in order from the top) in each row in the left column as output port identification information. The center column stores optimum position coordinates (Xo1, X1, X2, X3, Xo2 in order from the top) corresponding to the name of the output port for each row. The right column stores relative position coordinate differences (Yo1, Y1, Y2, Y3, 0) for each row. For example, when Rj = R1 is referred to as the output port, the coordinate database 112 outputs X1 as the optimum position coordinate and Y1 as the relative coordinate difference.

  Next, in step S102, the controller 40 refers to the coordinate table of the coordinate database 112 and obtains the optimum position coordinates of the reference output port Ro1. Thereafter, the movement switching plate 93 is moved so that the detected coordinate value of the position detector 110 matches the optimum position coordinate. The movement switching plate 93 is stopped in a position state where the position detector 110 has detected the optimum position coordinates of the reference output port Ro1. Thereafter, the controller 40 gives a desired rotation angle command to the stepping motor to the driving device 101 so that the output power of the reference output port Ro1 detected by the power meter 72a is maximized (power optimum position control). . For example, when ½ microstep driving is performed, the movement switching plate 93 is controlled to move by 0.1 μm when a ½ step angle is given as the rotation angle command.

FIG. 13 is a conceptual diagram showing a procedure for optimal power position control.
In the figure, the vertical axis indicates the output power detected by the power meter 72a, the horizontal axis indicates the position coordinate by the position detector 110, and the power tolerance curve 136 has a mountain shape having one maximum value.
As shown in the figure, the output power changes from climbing to descending with a change in the position coordinates of the movement switching plate 93 according to the rotation angle command output from the controller 40. When the maximum output power Pmax can be obtained at the peak portion, the position coordinate Xp is set as the optimum power position. At this time, the controller stores a plurality of previous coordinate values of the path traveled in the past. The position at which the power is maximized is obtained as follows.

First, when the value obtained by subtracting the past output power (the rotation angle command is 1/2 step angle before) from the output power at the current position is positive, the positive rotation angle command (1/2 step angle) is continuously given. Next, when the value obtained by subtracting the past output power from the output power at the current position changes from positive to negative, the optimum power position is determined from the coordinate values stored one or two before the coordinate value. Set.
On the other hand, when the value obtained by subtracting the output power of the past (the rotation angle command is 1/2 step angle before) from the output power at the current position is negative, the negative rotation angle command (1/2 step angle) is continuously given. . Next, when the value obtained by subtracting the past output power from the output power at the current position changes from negative to positive, the optimum power position is determined from the coordinate values stored one or two before the coordinate value. Set.
For example, as shown in the figure, it is assumed that the output power is Pi-2 when the position coordinates are Xi-2. At this time, the output power changes to Pi-1 when the position coordinates are Xi-1, and then the output power changes to Pi when the position coordinates are Xi. Further, assume that the output power changes to Pi + 1 when the position coordinate is Xi + 1. At this time, when the output power changes from Pi-2 to Pi-1 to Pi, the value obtained by subtracting the past coordinate value from the current coordinate value is positive. When the output power changes from Pi → Pi + 1, the value obtained by subtracting the past coordinate value from the current coordinate value is negative.
Therefore, the power optimum position is calculated by Xp = (Xi + Xi−1) / 2 using the past coordinate values Xi and Xi−1.

  In practice, the output power may have an extreme value at several millimeters before and after the maximum position. In this case, a power tolerance curve 136 is obtained once by gradually moving the position of the movement switching plate 93 at coarse step intervals before and after the optimum position coordinate Xo1 and plotting the output power of the reference output port Ro1 gradually. Record all plot values. A point at which the plotted power is maximized may be calculated based on the obtained power tolerance curve 136, and power optimum position control may be performed in the vicinity of the position that is the largest point.

  Needless to say, in each step of switch adjustment in steps S101 and S102, when measuring power with the power meter 72a, the input signal is appropriately turned on and off before and after the measurement.

  Next, in step S103, the difference between the optimum position coordinate X5 of the reference output port Ro1 measured in advance and the power optimum position Xp obtained in step S102 is calculated, and the absolute value D of the obtained difference is allowed. The position error is set in the controller 40.

Next, control during operation of the waveguide switch 70 in steps S104, S105, and S106 will be described.
First, the device under test is connected to the waveguide switch 70. In this example, the receiving waveguide terminals 22, 23, and 24 of the transmission / reception module 55 are connected to the output ports R1, R2, and R3 of the waveguide switch 70, respectively. The transmission waveguide terminal 21 of the transmission / reception module 55 is connected to the signal input device 71 through a waveguide (not shown) and supplies an input signal to the signal input device 71. As a result, the receiving waveguide terminals 22, 23, and 24 of the transmission / reception module 55 are ready to receive the output signal of the waveguide switch 70.

Next, in step S104, as described in FIG. 13, the power optimum position control of the reference output port Ro1 is executed to obtain the power optimum position Xp.
Here, when the power optimum position Xp is obtained by the power optimum position control, the difference between the power optimum position Xp and the optimum position coordinate Xo1 of the reference output port is calculated. When the absolute value of the obtained difference is within the allowable position error D, the process proceeds to step S105.
If the absolute value of the obtained difference is other than the allowable position error D, the process proceeds to step S106.

In step S105, the relative position coordinate difference Yj between the output port Rj and the reference output port Ro1 is added to the power optimum position Xp of the reference output port, and the added value is a target position for switching and connecting to the output port Rj. Let it be the coordinate Zj. For example, in the case of FIG. 12, the target position coordinates of the output port R2 are set as Z2 = Xp + Y1.
Next, the controller 40 calculates the step angle of the stepping motor so as to obtain the target position coordinate Zj, and supplies the calculated step angle to the drive device 101. The driving device 101 moves the position of the movement switching plate 93 based on the supplied step angle. At the same time, position measurement is performed by the position detector 110, and the step angle of the stepping motor is set to a ½ step angle so that the measured position coordinates coincide with the target position coordinates Zj (or the deviation is equal to or less than a predetermined value). Position feedback control (position control) is performed by appropriately adjusting the positive and negative multiples.

  As described above, the controller 40 controls the switching operation of the waveguide switch 70 to detect the occurrence of an error in the waveguide switch itself, and to output ports R1, R2 connected to the device under test. And the waveguide switch which reduces the loss difference between the ports of R3 can be obtained.

Note that the waveguide switch 70 is accompanied by deterioration in accuracy due to long-term use.
When the connection waveguide 140 is fixed to the output interface 92, the connection waveguide 140 is fastened to the end face of the output interface 92. A mechanical load is applied to the output interface 92 due to a minute difference in length of each connection waveguide 140.
This load repeatedly applies a load to the fastening portion between the output interface 92 and the support plate 94 every time the waveguide interface 56 is attached or detached. With this load, the relative position between the output interface 92 and the linear stage 96 and the relative position between the output interface 92 and the input interface 91 change, and the corresponding waveguide hole position changes slightly.

  If this relative position change is accumulated, a loss of the propagation signal exceeding the allowable value occurs until the input signal from the input port Ri is output at the output ports R1, R2, and R3. Alternatively, a large difference in propagation signal loss occurs between the output ports. In particular, when the output interface 92 is displaced in the rotational direction with respect to the input interface 91 or the switching moving plate 93 in spite of no change in the position of the reference output port Ro1, the relative position changes between the output ports. Therefore, the loss gap between output ports becomes large. As a result, a large error is given to the measurement result of the object to be measured even though it is determined in step S104 that it is within the allowable error. In some cases, although the transmission / reception module 55 itself has no problem in the target detection performance, a test failure that causes the target detection performance test of the transmission / reception module 55 to fail will occur.

  In this case, by providing an output port Ro (Ro1, Ro2) for power measurement, it is possible to detect a change in the signal propagation loss of the waveguide switch accompanying such a long-term change.

  For example, when the output signals of the output ports Ro1 and Ro2 are measured by the power meter 72a, the positions at which the power is maximized are Xp1 and Xp2. At this time, a coordinate difference D2 between Xp2 and Xp1 is calculated. When the difference between the obtained coordinate difference D2 and the relative position coordinate difference Yo2 of the coordinate table 115 measured in advance is equal to or larger than the allowable value, a setting deviation occurs in the waveguide switch 70, and the waveguide It is determined that an error has occurred in the switch 70 itself.

As another form, using the relative position coordinates of each output port with respect to this reference point, using the midpoint of the positions Xp1 and Xp2 where the output powers of the output ports Ro1 and Ro2 are maximum as reference points, Position control may be performed in the same manner as in step S105. For example, in the example of FIG. 12, the target position coordinate Z2 of the output port R1 may be set as Z2 = (Y1-Y02 / 2) + (Xp1 + Xp2) / 2.
In this case, the switching control of the waveguide switch is hardly affected by aging.

As described above, the waveguide switch according to this embodiment can accurately position the waveguide switch and reduce the loss of the propagation signal of the test system due to the switching of the connection of the waveguide switch. can do.
As a result, the loss gap between the output ports can be reduced, so that the electrical characteristic test of the wireless device can be efficiently performed without degrading the measurement quality.
It should be noted that this embodiment is extremely useful when used for testing at the time of mass production of radar, for example.

In the above description, an example in which only one waveguide switch is connected has been described. However, the number is not necessarily limited to one, and a plurality of waveguide switches may be connected in a tournament shape. Further, the number of waveguide output ports in the waveguide switch is not limited to five, and a plurality of ports may be provided.
Needless to say, the waveguide switch may have a plurality of input ports.

Embodiment 2. FIG.
In the first embodiment, the example in which the output port of the waveguide switch is connected to the receiver side of the transmission / reception module has been described. However, the output port of the waveguide switch is connected to the transmitter side of the transmission / reception module. It may be an input port.
That is, in this embodiment, the case where the waveguide switch has a plurality of input ports and one output port will be described.

FIG. 13 is a diagram illustrating a configuration of a control system of the waveguide switch according to the second embodiment.
In the figure, the waveguide switch 70 includes input ports R1, R2, and R3 and an output port Ri, and is the same as that described in the first embodiment. Will be described.
The input ports R1, R2, and R3 of the waveguide switch 70 are connected to the output terminals of the objects to be measured 551, 552, and 553, respectively. The device under test is configured by the transmission / reception module 55 described in the first embodiment, for example. In this example, the transmission waveguide terminals of a plurality of (three) transmission / reception modules 55 are connected to the input ports R1, R2, and R3 of the waveguide switch 70, respectively. In other words, by performing connection switching of input ports with the waveguide switch 70, it is possible to sequentially perform transmission tests on the plurality of transmission / reception modules 55.

  The output port Ri of the waveguide switch 70 is connected to the coupler 200. Coupler 200 has one branch connected to power meter 83. The other branch is connected to the frequency analyzer 50. The frequency analyzer 50 performs spectrum analysis of the transmission signals of the devices under test 551, 552, and 553, and performs a predetermined transmission characteristic test. The power meter 83 measures the output power of the output signal of the waveguide switch 70.

The controller 40 automatically controls the start and end of the test by controlling on / off of transmission signals of the devices under test 551, 552, and 553.
The controller 40 controls the connection switching of the waveguide switch 70 by driving the driving device 101. The driving device 101 is the same as that in the first embodiment. The controller 40 can record the spectrum analysis result of the frequency analyzer 50.
The controller 40 is connected to the power meter 83 and the output power measured by the power meter 83 is input.

Next, the operation of the control system for the waveguide switch according to the second embodiment will be described.
The controller 40 gives a desired rotation angle command (step angle) to the stepping motor constituting the driving device 101. As a result, the movement switching plate 93 of the waveguide switch 70 moves along the axis of the linear guide by a movement distance corresponding to a predetermined step angle. At this time, it is preferable to improve the position resolution by performing microstep driving.

As the movement switching plate 93 of the waveguide switch 70 moves, the power of the output signal measured by the power meter 83 changes.
At this time, if the measured power is moving in the increasing direction, a step angle with the same sign is further given. On the other hand, if the measured power is moving in a decreasing direction, a step angle with an opposite sign is given.
Further, when the movement switching plate 93 is moved and the power measured by the power meter 83 changes from increasing to decreasing, it is determined that the power has passed the maximum point, and the minimum step angle (1/2 microstep) In the case of driving, the stepping motor is reversely rotated by a half step angle).
As a result, the movement switching plate 93 is moved to a position where the input signal from the input port Rj is maximum coupled to the output port. That is, when the input port is switched and connected, the drive device 101 is controlled so that the movement switching plate 93 is moved to a position where the output power of the output port is maximized (power optimum control is performed).
Therefore, the switching of the waveguide switch can be controlled so that the output power of the output port becomes an optimum level.
Of course, it goes without saying that feedback control may be performed by a servo system using a DC motor so that the power of the power meter 83 is maximized.

Since there are a plurality of input ports of the waveguide switch (three in the example in the figure), it is necessary to move a predetermined waveguide of the movement switching plate 93 to a desired input port. However, there is a region between the input ports where the transmission signal of the device under test is output between the waveguides, so that no signal is output from the output port Ri and the power level drops.
Since optimal power control cannot be performed in this region, the rotation angle command for the stepping motor may be set so that the input port of the waveguide switch is moved to a region where the power level does not drop. In this case, it is only necessary to rotate the stepping motor by a preset predetermined angle (an integer multiple of the step angle) (so-called feedforward control is performed). Of course, it goes without saying that position control may be used in combination so as to avoid a region where the power level drops by providing a position detector.

In this embodiment, simultaneously with signal measurement by the frequency analyzer 50, the power level of the signal output from each input port to the output port can be directly measured.
For this reason, each input port of the waveguide switch can be accurately positioned only by performing power optimum position control such as moving the movement switching plate to a position where the output power of the input port is maximized.
As a result, the loss gap between the input ports at the time of connection switching can be reduced, and position detection is not required. Therefore, it is possible to install a position detector or perform prior position setting as described in the first embodiment. It becomes unnecessary.

It is a figure which shows the structural example of the FM-CW radar concerning this invention. It is a figure which shows the structural example of the signal generator of FM-CW radar. It is a figure which shows the transmission wave and reception wave of FM-CW radar of Embodiment 1. FIG. It is a figure which shows the frequency spectrum of the beat signal of FM-CW radar of Embodiment 1. FIG. It is a figure which shows the structure of the radar test apparatus of Embodiment 1. It is a figure which shows the structure of a signal input device. It is a figure which shows the example of a pattern of a target spectrum. 1 is a diagram illustrating a configuration of a waveguide switch according to a first embodiment. FIG. 5 is a diagram illustrating a switching operation of the waveguide switch according to the first embodiment. FIG. 3 is a diagram illustrating a configuration of a control system of the waveguide switch according to the first embodiment. FIG. 5 is a flowchart illustrating a control operation of the waveguide switch according to the first embodiment. It is a figure which shows the coordinate table of Embodiment 1. FIG. It is a figure explaining the power maximum position control of Embodiment 1. FIG. 6 is a diagram illustrating a configuration of a control system of a waveguide switch according to a second embodiment. FIG.

Explanation of symbols

  1 Modulator, 2 Oscillator, 3 Directional Coupler, 4 Transmitting Antenna, 5 Receiving Antenna, 6 Mixer, 7 Receiver, 8 D / A Converter, 9 Frequency Analyzer, 10 Target Detector, 11 Distance / Speed Calculation 20 FM-CW radar, 40 controller, 51 transmitter, 52 receiver, 50 frequency analyzer, 500 radar signal processor, 55 transceiver module, 70 waveguide switch, 71 signal input unit, 72a, 72b power Meter, 80 delay line, 82 variable attenuator, 83 power meter, 91 input interface, 92 output interface, 93 movement switching plate, 94 support plate, 95 pedestal, 96 linear stage, 100 radar test device, 101 drive device, 110 position Detector, 112 coordinate database, 200 coupler.

Claims (6)

An input interface having a waveguide;
An output interface having a plurality of waveguides;
A movement switching unit that is disposed between the input interface and the output interface, and includes a plurality of waveguides that respectively connect the waveguide of the input interface and at least one waveguide of the output interface; ,
A drive unit for linearly moving the movement switching unit;
A position detection unit for detecting a movement position of the movement switching unit;
A power monitor for measuring an output signal output from a part of the waveguide of the output interface;
The position reference of the movement switching unit is set so that the power of the output signal measured by the power monitor becomes an optimum level, and the difference between the set position reference and the movement position detected by the position detection unit is set. Based on the control unit for controlling the position of the movement switching unit,
A waveguide switch comprising: The power monitor measures an output signal output from a reference waveguide that is not connected to the object to be measured to which the output interface is connected,
The control unit sets an optimum position of the reference waveguide so that the power of the output signal measured by the power monitor becomes an optimum level, and sets the optimum position and other preset guidance values. The target position is the sum of the relative position differences between the wave tube and the reference waveguide.
2. The waveguide switch according to claim 1, wherein the position of the movement switching unit is controlled based on a difference between the target position and a movement position detected by the position detection unit. 2. The waveguide switch according to claim 1, wherein the waveguide switch has at least two measurement waveguides, and each output signal of the measurement waveguide is measured by a power monitor. . The waveguide switch has at least two measurement waveguides;
2. The waveguide switch according to claim 1, wherein the controller sets a position where the output power of each of the measurement waveguides is optimum as a position reference. An input interface having a plurality of waveguides;
An output interface having a waveguide;
A movement switching unit disposed between the input interface and the output interface, and having a plurality of waveguides respectively connecting at least one waveguide of the input interface and the waveguide of the output interface; ,
A drive unit for linearly moving the movement switching unit;
A power monitor for measuring an output signal output from a part of the waveguide of the output interface;
A control unit that moves the movement switching unit so that the power of the output signal measured by the power monitor is at an optimum level;
A waveguide switch comprising: A moving step that is disposed between the input interface and the output interface and moves a movement switching unit having a plurality of waveguides;
A position detecting step for detecting a moving position of the movement switching unit;
A power measurement step of measuring an output signal output from the waveguide of the output interface connected to the waveguide of the movement switching unit;
The position reference of the movement switching unit is set so that the measurement power of the power measurement step becomes an optimum level, and the movement is performed based on the difference between the set position reference and the movement position detected by the position detection unit. A position control step for controlling the position of the switching unit;
And a waveguide switching method.

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