A millimeter wave interferometer

Abstract

The application discloses a kind of millimeter wave interferometer, belong to electronic signal equipment technical field one kind of instrument, its technical scheme includes: millimeter wave signal transceiver module is provided with two phase-locked loops, two phase-locked loops pass through the input of reference clock signal, generate two microwave signals, two microwave signals are respectively the driving signal of transmission channel and the driving signal of receiving channel local oscillator;The transmission channel driving signal is divided into two millimeter wave signals after frequency multiplication filtering, and the echo of two millimeter wave signals is mixed with receiving local oscillator signal through coupler, obtains two intermediate frequency test signals;After IQ mixing, the signal is transported, enters ADC sampling and carries out analog-digital conversion, and the change of the density of the object to be measured can be tested by the phase change of millimeter wave signal.The application provides a kind of millimeter wave interferometer, can realize accurate test plasma electron density radial distribution, improves the diagnosis cutoff density of plasma.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of electronic signal equipment, and particularly relates to a millimeter wave interferometer. BACKGROUND

[0002] Plasma is a basic form of matter, and is the fourth form of matter in addition to solid, liquid and gas. Plasma is a complex multi-parameter system, and diagnosis of parameters such as electron density, collision frequency, electron temperature, active particle density and electron energy distribution is an important work of plasma research. A typical diagnosis method in the microwave diagnosis method is the microwave interference method, which obtains information such as the electron density of the plasma by measuring the changes in parameters such as the amplitude and phase information of the microwave signal before and after passing through the plasma, and in this method, since the antenna does not directly contact the plasma and the power of the microwave is very small when the microwave is transmitted in the plasma, the measurement of the electron density of the plasma by the microwave interferometer has little effect on the characteristic parameters of the plasma, and has a high time resolution, so that transient measurement can be performed.

[0003] However, a single-channel microwave interferometer is currently commonly used, and this single-channel test method needs to estimate the distribution density to obtain relatively accurate results, and the test sensitivity of the microwave frequency band interferometer is low when the microwave frequency band is lower than the increasing cutoff density of plasma diagnosis. Therefore, the current mainstream interferometer test equipment has rough test results and low test sensitivity. SUMMARY

[0004] The purpose of the present application is to provide a millimeter wave interferometer, which increases the number of transceiving channels to 2 channels, can collect the electromagnetic wave change information at different positions of the plasma in the radial direction at the same time under the condition that the distribution of the plasma electron density is unknown, and can realize accurate testing of the radial distribution of the plasma electron density; at the same time, the working frequency of the transmitting signal and the receiving channel is increased to the millimeter wave Ka frequency band, which increases the cutoff density of the plasma diagnosis.

[0005] The purpose of the present application is achieved by a millimeter wave interferometer, comprising:

[0006] A signal acquisition module, wherein a crystal oscillator in the signal acquisition module outputs a reference clock signal;

[0007] A millimeter wave signal transceiving module for receiving the reference clock signal and generating a microwave signal; and

[0008] The millimeter wave signal transceiving module is provided with two phase-locked loops, and the two phase-locked loops generate two microwave signals through the input of the reference clock signal, and the two microwave signals are respectively a driving signal of a transmitting channel and a driving signal of a local oscillator of a receiving channel;

[0009] The transmit channel driving signal is divided into two millimeter wave signals after frequency multiplication filtering, and the echoes of the two millimeter wave signals are mixed with the receiving local oscillator signal through a coupler to obtain two intermediate frequency test signals.

[0010] The driving signal of the receiving channel local oscillator is mixed with the coupled signal of the transmit channel output signal after frequency multiplication to obtain an intermediate frequency reference signal.

[0011] The intermediate frequency reference signal and the two intermediate frequency test signals enter the signal acquisition module through the connector, and after IQ mixing, the signals are transmitted into the ADC sampling for analog-digital conversion, and the change of the density of the measured object can be tested through the phase change of the millimeter wave signal.

[0012] Further, the two millimeter wave signals are output through a coaxial connector.

[0013] Further, the signals after entering the ADC analog-digital conversion are sampled, and after digital signal processing, they are transmitted to the upper computer through the serial port and the network port.

[0014] Further, the signal working frequency of the millimeter wave transceiver module is the millimeter wave Ka band.

[0015] Further, two I signals and two Q signals are output after IQ mixing.

[0016] Further, the length of the millimeter wave transceiver module body is 280mm, the width is 180mm, and the height is 40mm.

[0017] Further, the length of the signal acquisition module body is 140mm, the width is 80mm, and the height is 15.5mm.

[0018] Further, the millimeter wave transceiver module body and the signal acquisition module body are both sealed aluminum cavities.

[0019] The beneficial effects of the present application are as follows:

[0020] In the present application, the number of transceiver channels is increased to 2 channels, which can collect the electromagnetic wave change information at different positions of the plasma at the same time under the condition that the plasma electron density distribution is unknown, and can realize accurate testing of the radial distribution of the plasma electron density; at the same time, the working frequency of the transmit signal and the receiving channel is increased to the millimeter wave Ka band, which improves the diagnostic cutoff density of the plasma. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the drawings required to be used in the description of the specific embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference signs. In the drawings, the elements or parts are not necessarily drawn according to the actual proportions.

[0022] Figure 1 It is a top view of the main body of the millimeter wave signal transceiver module of the present application.

[0023] Figure 2 It is a right view of the main body of the millimeter wave signal transceiver module of the present application.

[0024] Figure 3 It is a left view of the main body of the millimeter wave signal transceiver module of the present application.

[0025] Figure 4 It is a top view of the main body of the signal acquisition module of the present application.

[0026] Figure 5 It is a right view of the main body of the signal acquisition module of the present application.

[0027] Figure 6 It is a left view of the main body of the signal acquisition module of the present application.

[0028] In the drawings, 1 is the main body of the millimeter wave signal transceiver module, 2 is the millimeter wave signal transceiver channel 1, 3 is the intermediate frequency reference signal output channel, 4 is the millimeter wave signal transceiver channel 2, 5 is the intermediate frequency test signal output channel 1, 6 is the synchronous clock input channel, 7 is the intermediate frequency test signal output channel 2, 8 is the main body of the signal acquisition module, 9 is the network port, 10 is the synchronous clock output interface, 11 is the serial port, 12 is the intermediate frequency test signal input interface, 13 is the intermediate frequency reference signal input interface, and 14 is the intermediate frequency test signal input interface 2. DETAILED DESCRIPTION

[0029] The embodiments of the technical solutions of the present application will be described in detail below with reference to the drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present application, and therefore only serve as examples, but cannot limit the protection scope of the present application.

[0030] It should be noted that, unless otherwise specified, the technical terms or scientific terms used in the present application should be understood as the usual meanings understood by the skilled in the art to which the present application belongs.

[0031] Reference Figures 1-6 A millimeter wave interferometer, comprising:

[0032] A signal acquisition module, a crystal oscillator in the signal acquisition module outputs a reference clock signal;

[0033] A millimeter wave signal transceiver module for receiving a reference clock signal and generating a microwave signal; and

[0034] The millimeter wave signal transceiver module is provided with two phase-locked loops, which generate two microwave signals through the input of the reference clock signal, and the two microwave signals are respectively the driving signal of the transmission channel and the driving signal of the receiving local oscillator;

[0035] The transmission channel driving signal generates two millimeter wave signals after frequency multiplication filtering and power division, and the echo of the two millimeter wave signals is mixed with the receiving local oscillator signal through a coupler to obtain two intermediate frequency test signals;

[0036] The driving signal of the receiving channel local oscillator is mixed with the coupling signal of the transmission channel output signal after frequency multiplication to obtain an intermediate frequency reference signal;

[0037] One intermediate frequency reference signal and two intermediate frequency test signals enter the signal acquisition module through the connector, and after IQ mixing, the signal is transported into the ADC sampling for analog-digital conversion, and the change of the density of the measured object can be tested through the phase change of the millimeter wave signal.

[0038] As a preferred mode of the embodiment, in the signal acquisition module, the crystal oscillator output generates an electrical signal through a crystal oscillator, and the electrical signal is output through a synchronous clock output interface 10 arranged on one side of the main body 8 of the signal acquisition module. Figure 5 In the embodiment, the reference clock signal generated by the crystal oscillator output is output through the synchronous clock output interface 10 arranged on one side of the main body 8 of the signal acquisition module.

[0039] The crystal oscillator (crystal oscillator) is an electronic oscillator circuit that uses a quartz crystal as a resonant element. It uses the piezoelectric effect of the quartz crystal to generate an electrical signal with very precise frequency. Crystal oscillator has the advantages of high stability, quality factor, small size and low cost, which makes it superior to other resonators such as LC circuit, ceramic resonator, fork, etc. Crystal oscillator plays a crucial role in electronic circuits, providing stable clock signals for various electronic devices, ensuring accurate operation of the device.

[0040] The working principle of the crystal oscillator is based on the piezoelectric effect of the quartz crystal, that is, when an electric field is applied to the two electrodes of the quartz crystal, the crystal will produce mechanical deformation; conversely, if mechanical pressure is applied to the two ends of the crystal, the crystal will generate an electric field. This phenomenon is reversible, and by applying an alternating voltage to the two ends of the crystal, the wafer will produce mechanical vibration and an alternating electric field. Under certain conditions, this vibration and electric field will reach a certain frequency, i.e. the piezoelectric resonance frequency, so that the frequency of the oscillator is very stable.

[0041] The phase-locked loop is a kind of voltage generated by phase synchronization, to tune the voltage-controlled oscillator to generate target frequency negative feedback control system. The frequency and phase of the loop internal oscillation signal are controlled by the external input reference signal, the frequency of the output signal is automatically tracked to the input signal frequency, generally used in closed-loop tracking circuit. It is a method to make the frequency more stable in radio transmission, mainly VCO (voltage-controlled oscillator) and PLL (phase-locked loop), the voltage-controlled oscillator gives a signal, part of which is output, and the other part is compared with the local oscillator signal generated by the PLL through frequency division, in order to keep the frequency unchanged, the phase difference should not change, if there is a change in phase difference, the voltage of the voltage output end of the PLL changes to control the VCO until the phase difference is restored, and the purpose of phase locking is achieved. The closed-loop electronic circuit can make the frequency and phase of the controlled oscillator maintain a certain relationship with the input signal.

[0042] As a preferred, two said millimeter wave signal, through the coaxial connector output.

[0043] As a preferred way of this embodiment, two said millimeter wave signal through the two millimeter wave signal transceiver channel set on one side of the millimeter wave signal transceiver module main body 1 signal output or input. Two said millimeter wave signal transceiver channel is millimeter wave signal transceiver channel 1 and millimeter wave signal transceiver channel 2 respectively.

[0044] The intermediate frequency reference signal is output through the intermediate frequency reference signal output channel 3 set between the two said millimeter wave signal transceiver channel.

[0045] Two said intermediate frequency test signal through the two intermediate frequency test signal output channel set on the opposite side of the intermediate frequency reference signal output channel 3 of the millimeter wave signal transceiver module main body 1 signal output.

[0046] The signal of the synchronous clock output interface is transmitted through the synchronous clock input channel 6 set on the millimeter wave signal transceiver module main body 1, and the synchronous clock input channel 6 is set between the two said intermediate frequency test signal output channel. Two said intermediate frequency test signal output channel is intermediate frequency test signal output channel 1 and intermediate frequency test signal output channel 2 respectively.

[0047] As a preferred, through the sampling of the signal after entering the ADC analog-to-digital conversion, the digital signal processing is transmitted to the host computer through the serial port and the network port.

[0048] Referring to Figure 4 and Figure 5 In the signal acquisition module main body 8, the network port 9 is set on one side of the synchronous clock output interface 10, and the serial port 11 is set on the opposite side of the synchronous clock output interface 10.

[0049] Two intermediate frequency test signals are input through the intermediate frequency test signal input interface 12 arranged on one side of the serial port 11, and an intermediate frequency reference signal is input through the intermediate frequency reference signal input interface 13 arranged between the two intermediate frequency test signal input interfaces 12.

[0050] Preferably, the signal operating frequency of the millimeter wave signal transceiver module is in the Ka frequency band of millimeter waves.

[0051] Preferably, two I signals and two Q signals are output after IQ mixing.

[0052] As a preferred mode of the embodiment, the IQ mixing is a double balanced mixer, which can be used for down-conversion to generate baseband I and Q signals, and can also be used as a mirror suppression mixer for up-conversion to convert the baseband I and Q signals into a single sideband modulation signal; a wideband 90° bridge and a wideband in-phase power divider are connected to the double balanced mixer; the wideband in-phase power divider is used to realize in-phase power division of the input radio frequency signal and output two radio frequency signals with consistent amplitude and phase; and the wideband 90° bridge is used to realize quadrature output of the local oscillator signal.

[0053] Preferably, the length of the millimeter wave signal transceiver module body is 280 mm, the width is 180 mm, and the height is 40 mm.

[0054] Preferably, the length of the signal acquisition module body is 140 mm, the width is 80 mm, and the height is 15.5 mm.

[0055] Preferably, the millimeter wave signal transceiver module body and the signal acquisition module body are both sealed aluminum cavities.

[0056] The working principle and process of the application are as follows:

[0057] The signal acquisition module in the millimeter interferometer provided by the application outputs a reference clock signal.

[0058] The millimeter wave signal transceiver module is used for receiving the reference clock signal and generating a microwave signal; and the millimeter wave signal transceiver module is provided with two phase-locked loops, which generate two microwave signals through the input of the reference clock signal, and the two microwave signals are respectively a driving signal of a transmitting channel and a driving signal of a local oscillator of a receiving channel.

[0059] The transmit channel drive signal is filtered and frequency-multiplied to generate two millimeter wave signals, the two millimeter wave signals are output through a coaxial connector, and the output signal can be radiated to the object to be measured through a feed line, and the echo of the two millimeter wave signals after transmission in the object to be measured medium is coupled with the receive local oscillator signal to obtain two intermediate frequency test signals;

[0060] The drive signal of the receive channel local oscillator is frequency-multiplied and mixed with the coupled signal of the transmit channel output signal to obtain an intermediate frequency reference signal;

[0061] The intermediate frequency reference signal and the two intermediate frequency test signals enter the signal acquisition module through the connector, and the signals are transported after IQ mixing, enter the ADC sampling for analog-digital conversion and acquisition, and are sent to the host computer through the serial port, the host computer can record the IQ change to represent the amplitude and phase change of the millimeter wave signal, and the phase change of the millimeter wave signal can test the change of the object density.

[0062] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should be covered in the scope of the claims and the specification of the present application.

Claims

1. A millimeter wave interferometer, characterized by, The application relates to a millimeter wave signal transceiver module. The application relates to a millimeter wave signal transceiver module. The millimeter wave signal transceiver module is provided with two-phase phase-locked loops, two-phase millimeter wave signals are generated through input of the reference clock signal, and the two-phase millimeter wave signals are respectively a driving signal of a transmitting channel and a driving signal of a receiving local oscillator; The transmitting channel driving signal is subjected to frequency multiplication filtering and power division to generate two-phase millimeter wave signals, echo of the two-phase millimeter wave signals is subjected to mixing with a receiving local oscillator signal through a coupler to obtain two-phase intermediate frequency test signals; The driving signal of the receiving local oscillator is subjected to frequency multiplication and mixing with a coupling signal of the transmitting channel output signal to obtain a phase intermediate frequency reference signal; The phase intermediate frequency reference signal and the two-phase intermediate frequency test signals enter a signal acquisition module through a connector, are subjected to IQ mixing, and then output signals, enter ADC sampling for analog-digital conversion, and the density change of a to-be-tested object can be tested through phase change of the millimeter wave signals; The signals after ADC analog-digital conversion are sampled, are subjected to digital signal processing, and are transmitted to an upper computer through a serial port and a network port; IQ mixing is carried out to output two-phase I signals and two-phase Q signals. The two-phase millimeter wave signals are output through a coaxial connector. The signal working frequency of the millimeter wave signal transceiver module is a millimeter wave Ka frequency band.

2. The millimeter wave interferometer of claim 1, wherein, The length of the millimeter wave signal transceiver module body is 280 mm, the width is 180 mm, and the height is 40 mm.

3. The millimeter wave interferometer of claim 1, wherein, The length of the signal acquisition module body is 140 mm, the width is 80 mm, and the height is 15.5 mm.

4. The millimeter wave interferometer of claim 1, wherein, The millimeter wave signal transceiver module body and the signal acquisition module body are both sealed aluminum cavities.

5. The millimeter wave interferometer of claim 1, wherein, ​ 6. The millimeter wave interferometer of claim 1, wherein, ​

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