KR100693315B1 - Multi-factor Test Apparatus and Method Using Phase Detection Device in Continuous Wave Mode - Google Patents

Abstract

A multipactor testing system and method using a phase detecting device in a continuous wave mode are provided to detect the multipactor generating time and exact RF(Radio Frequency) input power even in using a continuous wave as an RF signal source and to test a multipactor of all kinds of RF passive elements with low cost and simple structure. A multipactor testing system using a phase detecting device in a continuous wave mode is composed of a vacuum chamber(400) equipped with a test object(420); an RF signal generator for applying a continuous wave type RF signal to the test object from the outside of the vacuum chamber; an RF coupler electrically connected between the RF signal generator and the test object to extract an RF input signal applied from the RF signal generator and an RF reflected signal reflected from the test object; and an RF mixer detecting the phase difference between the RF input signal and the RF reflected signal by mixing the RF input signal and the RF reflected signal extracted by the RF coupler.

Description

Multifactor test apparatus using phase detection device in continuous wave mode and method thereof

1 and 2 is a block diagram showing a multi-factor test apparatus according to the prior art,

3 is a block diagram showing an embodiment of a multi-factor test apparatus according to the present invention;

FIG. 4 is a circuit diagram showing the configuration of Test-A of FIG. 3;

5 is a circuit diagram showing the configuration of the test-ade B of FIG.

6 is a block diagram schematically showing the configuration of a multi-factor test apparatus according to the present invention;

7 is a flow chart showing a multi-factor test method according to an embodiment of the present invention;

8 is a photograph of a multi-factor test test subject according to the present invention, and

9 is a graph showing the voltage value of the DC detection signal of the mixer according to an embodiment of the present invention.

** Description of symbols for the main parts of the drawing **

100: test aid A 200: test aid B

300: Test Aid C 400: Vacuum Chamber

110: RF generating signal source 111, 112, 210: RF power meter

211, 330: Spectrum Analyzer 113: DC Voltmeter

411: electron gun controller 410: micro current measuring instrument

412: temperature sensor detector 440: electron gun

430: Faraday cup 420: Subject

120, 121, 250: Isolator 130: High power amplifier

140, 240, 310: Bandpass filter 160, 161, 280: Attenuator

260, 320: low noise amplifier 270, 271, 230: load resistor

170: RF mixer 500: phase detection device diagram

150, 151, 220, 221: RF Coupler

The present invention relates to a multipactor test apparatus for satellite passive passive elements, and is particularly input to a device under test using an RF coupler and a mixer for a continuous wave mode test. The present invention relates to a multifactor test apparatus using a phase detector and a method thereof in a continuous wave mode in which a difference between an RF signal and an RF signal reflected from an object is converted into a DC voltage to detect a multifactor phenomenon.

Through the multi-factor test apparatus and method according to the present invention, it is possible to perform an accurate multi-factor certification test on a satellite RF passive component.

Multipactor (MP) is a discharge phenomenon occurring on the surface of a high frequency component in a vacuum state. Multi-factor phenomena occur in a vacuum of 10 ^-4 Torr or less and cause resonances with free electrons in the device when RF energy above an appropriate level passes through high-frequency passive devices (especially devices having a cavity, waveguide, etc.). And a secondary electron emission. As a result, the rapidly accelerated and increased electrons collide with the inner wall of the device to release other secondary electrons, thereby rapidly increasing the number of electrons. This phenomenon is called multipactor discharge, which causes corrosion of the surface of the component, which can cause performance degradation and physical structural damage of satellite RF passive components, as well as the inability to perform satellite missions. have.

Therefore, in order to prevent this phenomenon, RF space components are verified through certification tests.

1 is a diagram showing a standardized test method for multi-factor sensitivity test in the European Space Agency (ESA). Because detection of multifactor occurrences is not easy, ESA recommends using two or more methods simultaneously. In FIG. 1, the multi-factor test applies a phase nulling system as a main detection method, and additionally applies input / reflective power, third harmonic detection, and an electronic meter. In addition, the ESA recommends the use of pulse-type signals as RF signal sources because it is easy to generate / detect multi-factors for pulse-type RF signal sources in phase nulling systems. When multifactor occurs, noise appearing on the spectrum analyzer in the phase nulling system appears in the form of spark / burst noise near the envelope of the pulse model. This method is difficult to detect when using a continuous wave (RF) signal source. Therefore, the multi-factor test method using the conventional phase nulling system is not easy to detect in the multi-factor test for the RF signal source in the continuous wave mode, it is impossible to measure the phase change before the multi-factor generation, and the detection is not easy. There is a problem.

2 illustrates a method of detecting noise of two signals through a spectrum analyzer after passing a coupler, a variable resistor, and a variable phase shifter through an RF input power (Pin) and an output power (Vout) passing through an object. The figure shown. When the multi-factor phenomenon of the RF device occurs, the most sensitive part is a sharp increase in the amplitude and phase of the signal Vre reflected from the subject, whereas the output power (Vout) passing through the subject is multi-factor. When it occurs, the amount of change is weak and the output power is saturated. Therefore, the multi-factor test method illustrated in FIG. 2 has a difficulty in talking about the weak change and the initial generation step before the multi-factor is generated, which makes it difficult to identify the accurate multi-factor generated RF input power. In addition, the multi-factor test method of FIG. 2 can test only a structure having two ports among RF passive elements, and there is a problem in that multi-factor measurement is impossible for a 1-port passive element such as an antenna.

That is, it is difficult to detect the multi-factor generation phenomenon for the continuous wave mode RF signal source by the multi-factor test method of FIG. 1, and the multi-factor test on the 1 port RF device is impossible by the method of FIG. 2. Since measuring the output voltage of the sample, it is difficult to determine the exact multi-factor generated RF input power.

Accordingly, the present invention is to solve the above problems, using an RF coupler and a mixer as the main of the multi-factor detection method, an accurate multi-factor test device for continuous wave mode RF signal source and To provide a method and a multi-factor test apparatus and method using a phase detection device in a continuous wave mode that enables multi-factor sensitivity testing of all types of RF passive devices consisting of two or more ports as well as one port device. The purpose is.

In order to achieve the above object, the present invention provides a multi-factor test apparatus, comprising: a vacuum chamber in which a subject to be subjected to a multi-factor generation test is mounted; An RF signal generator configured to apply a continuous wave form RF signal to the subject under the vacuum chamber; An RF coupler electrically connected between the RF signal generator and the subject to extract an RF input signal applied from the RF signal generator and an RF reflected signal reflected from the subject; And an RF mixer which detects a phase difference between the RF input signal and the RF reflection signal by mixing the RF input signal and the RF reflection signal extracted by the RF coupler. do.

The vacuum chamber is characterized in that to maintain a vacuum state of less than 10 ^-4 Torr.

The signal output from the RF mixer is applied to the DC voltmeter,

The phase difference φ _re -φ _in of the RF input signal and the RF reflection signal is detected by φ _re -φ _in = cos ⁻¹ [V _out / α]. Where φ _in is the phase of the RF input signal, φ _re is the phase of the RF reflection signal, and α is the amplitude of the detection signal.

On the other hand, the multi-factor test method using the multi-factor test apparatus for achieving the object of the present invention, a) applying the RF power below the expected multi-factor generated power to the RF signal generator; b) increasing the RF power by a predetermined dB; c) observing whether the voltage value of the DC voltmeter representing the voltage of the signal input from the RF mixer changes rapidly while maintaining the applied RF power for 10 minutes; d) recording the input RF voltage of step b) and the output DC voltage of step c); e) determining whether a multi-factor occurs as a result of the observation of step c); f) if it does not occur in step e), returns to step b) to increase the RF input power by one step and repeat the process; And g) lowering the RF power when it is determined in step e) and inspecting a change in the vacuum chamber due to the multi-factor. It is characterized by consisting of.

When the expected multi-factor generation power in step b) is 6 to 3 dB, it is preferable to increase by 1 dB, and when the expected multi-factor generation power is below 3 dB, it is preferably increased by 0.5 dB.

The inspection of step g) is characterized by visual inspection and surface inspection.

There may be a plurality of embodiments of the present invention, hereinafter with reference to the accompanying drawings will be described in detail a preferred embodiment. This embodiment allows for a better understanding of the objects, features and advantages of the present invention.

Figure 3 is a block diagram showing an embodiment of a multi-factor test apparatus according to the present invention, Figure 4 is a view showing a test aid A of Figure 3, Figure 5 is a view showing a test aid B of FIG. FIG. 6 is a view illustrating a DC detection signal determination process according to an input signal and a reflected signal flow and a phase difference between signals of the multi-factor test apparatus of FIG. 3, FIG. 7 is a flowchart illustrating a multi-factor test method, and FIG. 8 is a multi-factor test method. A photograph of a 1pole resonator under test and FIG. 9 are graphs showing voltage values of DC detection signals output from a mixer.

As shown in FIG. 3, the multi-factor test apparatus according to the present invention is a vacuum chamber 400 in which a device under test (DUT) 420 is mounted, and a test for phase detection located in front of the test object 420. Test Aid A (100), Test Aid B (200) for analyzing the amount of change in the third harmonic component and the signal output from the subject 420, a test subject having a 3 port extra And a test aid C 300 for detecting a noise level at the port.

The vacuum chamber 400 mounts the object 420 to maintain a vacuum state. Multi-factor phenomena occur only when the vacuum level is less than 10 ^-4 Torr, so the vacuum factor is maintained at 10 ^-4 Torr. If the multi-factor is generated, the temperature change is detected using the temperature sensors 450 and 451 and the temperature sensor detector 412 attached to the subject 420, and the vacuum chamber (430) is detected through the free electron collector 430. The free electrons distributed in 400 are collected, and the amount of change is detected by converting an electron amount into a current value with a microcurrent measuring device 410 connected to the free electron collector 430. The subject 420 is an RF passive component of a satellite and is an RF space component to be tested by a multi-factor certification in order to prevent performance degradation and physical structural destruction due to a multi-factor phenomenon. As shown in FIG. 8, a 1 port RF passive element is also included.

The RF signal generator 110 is a device for generating a reference signal in the form of a continuous wave, which is a reference signal.

As shown in FIG. 4, the test aid A 100 includes a RF coupler 151 and a mixer 170, and is electrically connected to the front end of the object 420. That is, the multi-factor generation is detected by detecting a phase difference between the RF signal input and connected between the RF signal generator 110 and the object 420 and the RF signal reflected from the object. Since the reflection signal is used in front of the object 420, the multi-factor test may be performed even in the case of a 1-port RF device.

The test aid A 100 extracts the phase of the continuous wave RF signal source Vin , which is a reference signal, and the signal Vre reflected from the subject 420 through the RF coupler 151, and the RF mixer. Using 170 as a phase detector, the phase difference between the two input signals is detected from the output voltage Vout using the DC voltmeter 113. The RF coupler 150 distributes the input reference voltage Vin and the signal Vre reflected from the subject 420, and Vin is output to the JA3 line and applied to the RF power meter 111 so that the magnitude of the input voltage is increased. Vre is output to the JA4 line and applied to the RF power meter 112 so that the magnitude of the reflected voltage is detected. Reference numerals 120 and 121 denote isolators, 130 high power amplifiers, 140 band pass filters, and 160 and 161 attenuators.

The relationship between the RF input signal V _in , the continuous wave mode RF signal generated by the RF signal generator 110, the RF reflection signal V _re reflected from the subject, and the DC detection signal V _out due to the phase difference are as follows. It can be expressed by a formula, and the flow of the signal is as shown in FIG.

That is, when the RF input signal V _in is V _in = A ₁ cos (ω _in t + φ _in ) and the RF reflection signal V _re is V _re = A ₂ cos (ω _re t-φ _re ),

The combined wave (V _mix ) of the two may be referred to as V _mix = αcos (φ _re −φ _in ) + βcos (2ωt) + HOT.

4 and 6, the RF signal generator 110 is processed through an RF input signal, which is a continuous wave mode RF signal generated by the RF signal generator, and an amplifier, a filter, an attenuator, etc., which is reflected and output from the subject. In the RF input signal V _in 'RF reflected signal is denoted as V _re ', but for convenience, the following description is referred to as RF input signal (V _in ) and RF reflected signal (V _re ). The DC detection signal V _out according to the phase difference output from the RF mixer 170 for synthesizing the RF input signal Vin and the RF reflection signal Vre has infinite signals, but the largest signal among them is the input. The DC output signal voltage value (V _out ) for the phase difference between the two signals of and is filtered by the coupler 151, the attenuator 160, 161, and the band pass filter 140 as shown in Figs. The amplitude of the doubling frequency components and the higher order term (HOT) components. Therefore, the DC detection signal voltage (V _out ) is mostly due to the phase difference between the RF input signal (V _in ) and the RF reflection signal (V _re ), and the change of the amplitude values of the two signals is almost negligible.

Therefore, the DC detection signal Vout can be referred to as V _out ≒ αcos (φ _re -φ _in ), and the phase difference (φ _re -φ _in ) between the RF input signal and the RF reflection signal is φ _re -φ _in = cos. ^-1 [V _out / α].

Where V _in is the RF input signal, A1 is the amplitude of the RF input signal, ω _in is the frequency of the RF input signal, and φ _in is the phase of the RF input signal. V _re is the RF reflection signal, A2 is the amplitude of the RF reflection signal, ω _re is the frequency of the RF reflection signal, φ _re is the phase of the RF reflection signal. V _mix is a formula of Vre and Vin synthesized wave, V _out is a detection signal output from the RF mixer 170, HOT represents a higher order term (HOT).

Therefore, if the test is performed after the circuit configuration as shown in FIG. 3, even if the RF power of the continuous wave RF signal generator 110 is increased, the DC detection signal V _out is completely filtered against the higher order term before the multi-factor phenomenon occurs. Since it is not removed, the DC detection signal V _out is increased to a degree that does not affect the determination of whether or not the multi-factor is generated. However, when the multi-factor is generated, the RF input signal V _in , which is a reference signal, remains constant, but due to the resonance phenomenon with the free electrons in the subject, the reflected signal V _re is reflected in the subject 420. The phase breakage causes the DC detection signal (V _out ) value to reverse, and in addition, the DC detection signal (V _out ) value also changes due to the increase in the noise signal with an arbitrary phase over the entire frequency band. do. Since only the phase component of the signal that is changed compared to the reference signal proposed by the present invention is detected as the DC detection signal voltage change amount, it is possible to detect the phase of the RF reflection signal V _re according to the pure multi-factor generation. The tester can recognize the multi-factor generation by checking the DC detection signal, and can check the input RF power generated by the multi-factor by checking the RF power meter 111 at the time of the multi-factor generation. In addition, the signal of the DC voltmeter 113 and the RF power meter 111 may be output to a processor such as a PC to automatically check the multi-factor generation.

The test aid B 200 detects a multi-factor generation by analyzing the third harmonic component and the amount of change in the output of the actual signal, and outputs a high power output resistor 230 having a high power output from the subject 420. Terminating the signal, the signal strength is attenuated by the coupler 220 to 40dB and filtered by the third harmonic filter 420 to amplify the signal through the isolator 250 and LNA 260 to detect the amount of change in the third harmonic component In addition, the function of detecting the signal strength of the output by further lowering the strength of the signal through the coupler 221 to the attenuator 280.

When the test aid C 300 has a 3-port form, the test aid C 300 filters the noise level at the remaining ports except for the input and output by the filter 310 and amplifies the weak signal with the low noise amplifier 320. When the multi-factor occurs with the spectrum analyzer 330 is a device for checking the noise level.

By using test aids B and C together with test aids A, the reliability of the test results can be improved.

The phase detection method using the RF mixer 170, which is a multi-factor test method for the continuous wave mode using the multi-factor test apparatus of the present invention configured as described above, will be described in detail with reference to FIGS.

As shown in FIG. 3, the multi-factor test apparatus is configured for the continuous wave mode, and each of the test aids A, B, and C (100, 200, 300) is verified. Calibrate, calibrate and calibrate respective cable loss, set spectrum analyzers 211 and 330, and low noise amplifier (LNA) 260 320 and a high power amplifier (PA) 130 are set up. In addition, the degree of vacuum of the vacuum chamber 400 is checked, and an electron gun 440 and a free electron collector 430 are mounted.

On the other hand, Figure 7 is a flow chart displaying the satellite RF device authentication method according to the present invention, the multi-factor test method is a step S140 shows a detailed operation flow in sequence S141 to S149.

When the multi-factor test is started (S141), the power of the RF signal generator 110 is applied (S142). It is advisable to start the test with RF power applied below the expected multifactor generated power of 6dB.

The RF power is increased by 1 dB or 0.5 dB (S143). If the expected multi-factor generation power is 6 ~ 3dB, it is preferable to increase by 1dB, and if the expected multi-factor generation power is less than 3dB, it is desirable to increase by 0.5dB.

While maintaining the applied RF power for 10 minutes (S144), a sudden change in DC output voltage, RF input / output power, noise level, etc., which are signs of multi-factor generation, is observed. Measure and record the level of each item (S145), determine whether or not the multi-factor generation symptoms occur (S146), if not generated, return to step S143 to increase the RF input power by one step and repeat the above process.

 When the multi-factor generation symptoms are observed, the RF power of the continuous wave RF signal generator 110 is lowered (S147), and abnormalities are performed by performing visual inspection and surface inspection (S148) on changes caused by the multi-factor on the specimen in the vacuum chamber. Determine the presence.

An example in which the multi-factor test method is performed with a 1pole resonator as shown in FIG. 8 as a test object is as follows. The expected multifactor generated RF input power of the designed / fabricated sample subject is approximately 0.76 watts (28.8 dBm). Therefore, if the test is started with a power that is 6 dB lower than the expected multi-factor generated RF power, and the test is performed in 1 dB increments, as a result, the DC detection signal voltage value according to the phase difference of the RF mixer 170 generated by the continuous wave RF input power is determined. The change is shown in FIG.

In the continuous wave mode RF input power of 27 dBm or less, as shown in the present invention, the change in amplitude according to the amplitude of the input signal is shown to be smooth, and the input power is 27 dBm to 28 dBm. After increasing the voltage, the voltage of the DC detection signal output from the RF mixer decreased rapidly as the phase changed. In addition, the amount of change in the DC detection signal voltage was observed over time that the resonance between the free electrons and the RF field occurred due to the multi-factor. Therefore, as a result of the multi-factor test of the 1 pole resonator according to the present invention, it can be seen that the multi-factor occurs when the continuous wave mode RF input is about 28 dBm.

As such, in the present invention, in the case of the conventional phase nulling system, only the multi-factor test for the RF signal source in the form of pulse is possible, even when the continuous wave is used as the RF signal source, it is possible to determine the time of the multi-factor occurrence and the accurate RF input power. Will be.

It also improves the sensitivity of the detection method and enables multi-factor testing of 1 port devices such as antennas.

As described in detail above, the present invention can detect a multi-factor generation time and accurate RF input power even when using a continuous wave as an RF signal source, and can be applied to all types of RF passive devices with low cost and simple configuration. Multifactor testing is possible.

Claims (3)

In the multi-factor test apparatus, A vacuum chamber in which a subject to be tested for multi-factor generation is mounted; An RF signal generator configured to apply a continuous wave form RF signal to the subject under the vacuum chamber; An RF coupler electrically connected between the RF signal generator and the subject to extract an RF input signal applied from the RF signal generator and an RF reflected signal reflected from the subject; And An RF mixer configured to detect the phase difference between the RF input signal and the RF reflection signal by mixing the RF input signal and the RF reflection signal extracted by the RF coupler; Multi-factor test device using. The method of claim 1, By applying the signal (V _out ) output from the RF mixer to the voltmeter, The phase difference (φ _re -φ _in ) between the RF input signal and the RF reflection signal, Multi-factor test apparatus using a phase detection device in the continuous wave mode, characterized in that calculated by φ _re -φ _in = cos ^-1 [V _out / α]. Where φ _in is the phase of the RF input signal, φ _re is the phase of the RF reflection signal, and α is the amplitude of the output signal. In the multi-factor test method using the multi-factor test apparatus of any one of claims 1 to 2, a) applying RF power below an expected multi-factor generated power to the RF signal generator; b) increasing the RF power by a predetermined dB; c) observing whether the voltage value of the DC voltmeter representing the voltage of the signal input from the RF mixer changes rapidly while maintaining the applied RF power for 10 minutes; d) recording the input RF voltage of step b) and the output DC voltage of step c); e) determining whether a multi-factor occurs as a result of the observation of step c). f) if it does not occur in step e), returns to step b) to increase the RF input power by one step and repeat the process; And g) lowering the RF power if it is determined in step e) and inspecting a change due to a multi-factor in the specimen in the vacuum chamber; Multi-factor test method using a phase detection device in a continuous wave mode, characterized in that consisting of.

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