Vector measurement system and method for phased array chip calibration and application

Abstract

The invention provides a vector measurement system and method for phased array chip calibration and application. The vector measurement system comprises a frequency output device used for generating a first local oscillator signal, a second local oscillator signal and a third local oscillator signal; the terahertz light source is used for receiving the second local oscillator signal and radiating terahertz waves after frequency multiplication amplification; the receiver is used for receiving the third local oscillator signal and taking the third local oscillator signal as a fourth local oscillator signal after frequency multiplication amplification, and the fourth local oscillator signal is mixed with the terahertz signal to generate an intermediate frequency signal; the IQ demodulator is used for receiving and demodulating the intermediate frequency signal and the first local oscillator signal to obtain an output signal; and the wave absorbing device is arranged between the receiver and the terahertz light source and is used for preventing unmodulated terahertz waves from being aliasing with the terahertz signals and entering the receiver. The vector measurement system is simpler in design and can effectively avoid measurement errors caused by signal aliasing.

Description

Technical Field

[0001] The present application relates to the technical field of micro-nano manufacturing and the technical field of terahertz measurement, and in particular to a vector measurement system, method and application for phased array chip calibration. Background Art

[0002] With the continuous development of communication technology, the commercial spectrum has gradually expanded to millimeter waves, and terahertz will be used in the next generation of communication systems. However, with the increase of carrier frequency, the path attenuation of electromagnetic waves increases, and the saturated output power of the device decreases, resulting in a decrease in the working distance of the terahertz communication system. To overcome this problem, phased array technology is widely used in practical applications. Phased array technology can not only increase the directivity of electromagnetic wave radiation, but also increase the total output power of the system, thereby significantly improving the working distance of the system. Accurate calibration of phased array chips is a prerequisite for ensuring their effective operation in practical applications. Only after calibration can phased array chips be reliably applied to various systems.

[0003] At present, the commonly used phased array chip calibration methods are mainly divided into two categories: direct calibration method and indirect calibration method. The direct calibration method uses a vector network analyzer (VNA) to obtain the amplitude and phase modulation characteristics of the phased array chip by analyzing the amplitude and phase information of the network input and output signals. This method is the main method for calibrating low-frequency phased array systems, and has the characteristics of high accuracy and high efficiency. However, in the terahertz frequency band, a combination of VNA and spectrum extension modules is required to complete the measurement. At this time, the link complexity increases, the path parasitic effects are aggravated, and many measurement errors are caused. For example, parasitic capacitance causes the terahertz signal to have a feedback path, resulting in self-excitation. The indirect calibration method uses a superheterodyne RF link, uses one terahertz signal as the reference light, and the other terahertz signal as the measurement light. By comparing the amplitude and phase information of the reference light and the measurement light, the amplitude and phase modulation characteristics of the phased array chip can be obtained. However, the VNA measurement or superheterodyne measurement link measurement in the related technology has the problem of measurement errors caused by the unsophisticated design of the optical path and RF link and signal aliasing.

[0004] Based on this, the present application provides a vector measurement system, method and related equipment for phased array chip calibration. Summary of the invention

[0005] In view of the problems existing in the prior art, the present application provides a vector measurement system, method and application for phased array chip calibration.

[0006] The purpose of this application is achieved by the following technical solutions:

[0007] In a first aspect, the present application provides a vector measurement system for phased array chip calibration, the system comprising:

[0008] A frequency output device, the frequency output device is used to generate a first local oscillation signal, a second local oscillation signal and a third local oscillation signal;

[0009] A terahertz light source, the terahertz light source is used to receive the second local oscillation signal and radiate terahertz waves after frequency doubling and amplification, and the terahertz waves are used to generate terahertz signals after being modulated by the phased array chip to be tested;

[0010] A receiver, the receiver is used to receive the third local oscillator signal and the terahertz signal, the third local oscillator signal is used as a fourth local oscillator signal after frequency doubling and amplification, the fourth local oscillator signal is mixed with the terahertz signal to generate an intermediate frequency signal and output it;

[0011] An IQ demodulator, the IQ demodulator is used to receive the intermediate frequency signal and the first local oscillator signal and perform demodulation to obtain an output signal, and the output signal is used to obtain the amplitude modulation characteristics and phase modulation characteristics of the phased array chip to be tested;

[0012] A wave absorbing device is arranged between the receiver and the terahertz light source, and is used to prevent unmodulated terahertz waves from overlapping with the terahertz signal and entering the receiver.

[0013] In some possible implementations, the frequency output device is a frequency synthesizer; or, the frequency output device includes a function generator and a microwave source, the function generator is used to generate a reference signal and a first local oscillator signal, and the microwave source is used to receive and generate a second local oscillator signal and a third local oscillator signal based on the reference signal; the reference signal and the first local oscillator signal are phase synchronized.

[0014] In some possible implementations, the terahertz light source is used to receive the second local oscillator signal and radiate terahertz waves through a speaker after frequency doubling and amplification.

[0015] In some possible implementations, the first local oscillator signal and the intermediate frequency signal have the same frequency.

[0016] In some possible implementations, the reference signal is a 10 MHz signal.

[0017] In some possible implementations, the phased array chip to be tested is disposed on a translation platform, and the system further includes an off-axis parabolic mirror, which is disposed between the terahertz light source and the phased array chip to be tested, and is used to converge the terahertz wave to a target array element of the phased array chip to be tested.

[0018] In some possible implementations, the system further includes a beam splitter, which is disposed on an optical path between the phased array chip to be tested and the receiver, and is used to separate the terahertz signal from an unmodulated terahertz wave.

[0019] In a second aspect, the present application further provides a calibration method for a phased array chip of a vector measurement system according to any one of the first aspects, the method comprising:

[0020] performing calibration of the vector measurement system;

[0021] According to the actual measured frequency point, the output frequency and level of the first local oscillator signal of the frequency output device are set, and the output frequency and power of the second local oscillator signal and the third local oscillator signal are set;

[0022] The output signal of the IQ demodulator is acquired and processed to obtain the amplitude modulation characteristics and phase modulation characteristics of the phased array chip to be tested.

[0023] In some possible implementations, the calibrating the vector measurement system includes: performing displacement calibration and time stability calibration of the vector measurement system.

[0024] In a third aspect, the present application further provides an electronic device comprising one or more processors and a memory; one or more programs are stored in the memory and are configured to be executed by the one or more processors to perform any of the methods described in the second aspect.

[0025] In a fourth aspect, the present application further provides a computer-readable storage medium having instructions stored thereon, wherein when the instructions are executed by a processor, the processor implements the method as described in any one of the second aspects.

[0026] In a fifth aspect, the present application further provides a computer program product, wherein the computer program product comprises a computer program, and when the computer program is executed by at least one processor, the steps of any one of the methods described in the second aspect are implemented.

[0027] Compared with the prior art, this application has at least the following beneficial effects:

[0028] (1) The vector measurement system provided in the present application includes a frequency output device, a terahertz light source, a receiver, an IQ demodulator and an absorbing device, which reduces the complexity of the link and makes the system design more concise.

[0029] (2) The present application provides an absorbing device between the receiver and the terahertz light source, which can effectively prevent the unmodulated terahertz wave from overlapping with the terahertz signal and entering the receiver, thereby avoiding measurement errors caused by signal aliasing. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The present application is further described below in conjunction with the accompanying drawings and implementation methods.

[0031] Figure 1 It is a structural schematic diagram of a vector measurement system provided in an embodiment of the present application.

[0032] Figure 2 It is a structural schematic diagram of another vector measurement system provided in an embodiment of the present application.

[0033] Figure 3 It is a schematic diagram of the phase calibration result of the vector measurement system provided in an embodiment of the present application.

[0034] Figure 4 It is a schematic diagram of the amplitude calibration result of the vector measurement system provided in an embodiment of the present application.

[0035] Figure 5 Schematic diagram of the time stability of the vector measurement system provided in the embodiment of the present application.

[0036] Figure 6 It is a schematic diagram of the amplitude modulation characteristics and phase modulation characteristics measured by the vector measurement system provided in the embodiment of the present application.

[0037] Figure 7 It is a flow chart of a vector measurement method provided in an embodiment of the present application.

[0038] Figure 8 It is a structural schematic diagram of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0039] Below, in conjunction with the accompanying drawings and specific implementation methods, the present application is further described. It should be noted that, under the premise of no conflict, the various embodiments described below or the various technical features can be arbitrarily combined to form a new embodiment. The implementation procedures of the present application will be described below with reference to the accompanying drawings and preferred embodiments. Those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. The present application can also be implemented or applied through other different specific implementation procedures, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application. It should be understood that the preferred embodiments are only for illustrating the present application, not for limiting the scope of protection of the present application.

[0040] The following is a brief description of the technical field of the embodiments of the present application to facilitate understanding by those skilled in the art.

[0041] Phased array chips are the product of micro-nano manufacturing technology, usually composed of micron or nanometer-scale components, and can operate in the terahertz frequency band. The vector measurement system protected by this application can be used for quality control and performance testing in the micro-nano manufacturing process.

[0042] VNA measurement is used in related technologies. VNA measurement has the following situations: 1. Measurement frequency: The highest frequency of commercial VNA is 110GHz, and the conventionally available frequency is 60GHz, so it is impossible to directly complete terahertz vector measurement in higher frequency bands. The measurement frequency of VNA can be increased by adding a spectrum extension module, but there are compatibility issues between the spectrum extension module and the VNA device. Usually, due to the presence of high-frequency parasitic capacitance, a feedback path is formed, and a self-excited signal is generated, which is manifested as spikes and burrs on the scattering parameters, affecting the measurement accuracy. 2. Calibration error: The measurement accuracy is greatly affected by the calibration accuracy. When measuring phased array chips, the RF signal path is coupled from the coaxial line to the free space. There is a lack of corresponding calibration parts, and the measurement error is large. 3. Dynamic range: The dynamic range of VNA is limited, especially the maximum output power. VNA is aimed at small signal measurement occasions, so it is impossible to perform vector measurement of large signal electromagnetic fields. Based on this, superheterodyne measurement link measurement can be used.

[0043] However, the applicant has found that the use of superheterodyne measurement links has the following shortcomings: 1. Link complexity: The currently disclosed terahertz superheterodyne measurement links are relatively complex. As an example, the terahertz beam light field vector spatial distribution measurement method and test system disclosed in application number CN202310185159.4 adopts a different frequency dual local oscillator architecture, that is, a power divider is used to separate a signal in the local oscillator path and the radio frequency path as a reference signal for IQ demodulation. The architecture is characterized by strong universality. Microwave sources of different models and different phase noise levels can adopt this architecture, but the link is complex and the measurement accuracy is average. In other words, in the superheterodyne measurement link measurement in the related art, the IQ local oscillator signal link greatly increases the complexity of the link and increases the hardware cost; and the low-frequency noise signal is easily coupled to the IQ demodulator through the link, affecting the measurement accuracy; the IQ local oscillator link is separated by the microwave source, and the frequency spectrum contains the phase noise of the two microwave sources, and the phase noise is large, so the measurement accuracy is average. In addition, the terahertz superheterodyne vector measurement link in the related art does not consider the measurement error caused by background signal aliasing, nor does it consider the measurement error caused by reference signal phase noise.

[0044] Based on this, the present application provides a vector measurement system, method and related equipment for phased array chip calibration, which is more concise, flexible, reconfigurable and highly accurate. Simplicity is reflected in the design of the optical path and the RF link. For example, compared with the disclosed patents, the technical solution provided by the present application is more concise; flexible and reconfigurable means that the equipment and optical components in the system can be replaced according to the measurement requirements, such as IQ demodulator, AFG, terahertz light source, terahertz receiver, etc.; high precision means that the present application suppresses the background terahertz signal and the low phase noise reference signal through the absorbing device, thereby improving the IQ demodulation accuracy. The following will first describe the system, and then describe the method, etc.

[0045] System Embodiments.

[0046] See also Figure 1 and Figure 2 , Figure 1 is a structural schematic diagram of a vector measurement system provided in an embodiment of the present application, Figure 2 It is a structural schematic diagram of another vector measurement system provided in an embodiment of the present application, which is used to illustrate the test optical path of a single array element of a phased array chip.

[0047] The embodiment of the present application provides a vector measurement system for phased array chip calibration, the system comprising:

[0048] A frequency output device, the frequency output device is used to generate a first local oscillation signal, a second local oscillation signal and a third local oscillation signal;

[0049] A terahertz light source, the terahertz light source is used to receive the second local oscillation signal and radiate terahertz waves through a speaker after frequency doubling and amplification, and the terahertz waves are used to generate terahertz signals after being modulated by the phased array chip to be tested;

[0050] A receiver, the receiver is used to receive the third local oscillator signal and the terahertz signal, the third local oscillator signal is used as a fourth local oscillator signal after frequency doubling and amplification, the fourth local oscillator signal is mixed with the terahertz signal to generate an intermediate frequency signal and output it;

[0051] An IQ demodulator, the IQ demodulator is used to receive the intermediate frequency signal and the first local oscillator signal and perform demodulation to obtain an output signal, and the output signal is used to obtain the amplitude modulation characteristics and phase modulation characteristics of the phased array chip to be tested;

[0052] A wave absorbing device is arranged between the receiver and the terahertz light source, and is used to prevent unmodulated terahertz waves from overlapping with the terahertz signal and entering the receiver.

[0053] In the technical solution provided in this embodiment, the frequency output device is responsible for generating three local oscillator signals, namely, the first local oscillator signal, the second local oscillator signal and the third local oscillator signal. The terahertz light source receives the second local oscillator signal, and radiates the terahertz wave through the speaker after frequency doubling and amplification. The terahertz wave will be used to interact with the phased array chip to be tested, and generate a terahertz signal through modulation. It can be understood that the terahertz wave is modulated by the phased array chip, and its amplitude and phase are changed according to the characteristics of the chip to generate a terahertz signal carrying chip characteristic information. At the same time, the receiver receives the third local oscillator signal and multiplies and amplifies it as the fourth local oscillator signal. The fourth local oscillator signal is mixed with the terahertz signal modulated by the phased array chip to generate an intermediate frequency signal. The IQ demodulator receives the intermediate frequency signal and the first local oscillator signal, and performs a demodulation operation. The demodulated output signal contains the amplitude modulation characteristics and phase modulation characteristics of the phased array chip, which is used to evaluate the performance of the chip.

[0054] In addition, a wave absorbing device is set up. The wave absorbing device is located between the receiver and the terahertz light source. Its function is to prevent the unmodulated terahertz waves from overlapping with the modulated terahertz signals and prevent these unmodulated waves from entering the receiver, thereby avoiding interference with the measurement results.

[0055] Therefore, by using multiple local oscillator signals and IQ demodulators, the system can accurately measure the amplitude modulation characteristics and phase modulation characteristics of the phased array chip; the use of the absorbing device reduces the interference of unmodulated terahertz waves on the measurement, and improves the stability of the system and the accuracy of the measurement; the system includes a frequency output device, a terahertz light source, a receiver, an IQ demodulator and an absorbing device, which reduces the complexity of the link and makes the system design more concise.

[0056] In specific applications, the system design allows the replacement of components such as frequency output devices, terahertz light sources, receivers, and IQ demodulators to adapt to different measurement requirements and environments, enhancing the flexibility and reconfigurability of the system. Compared with existing technologies, the system design provided by this application is simpler, reduces link complexity, reduces hardware costs, and improves the system's anti-interference ability.

[0057] In summary, this technical solution provides a high-precision, high-stability, flexible and reconfigurable terahertz phased array chip calibration vector measurement system, which can effectively evaluate the performance of phased array chips.

[0058] In some embodiments, the frequency output device is a frequency synthesizer; or, the frequency output device includes a function generator and a microwave source, the function generator is used to generate a reference signal and a first local oscillator signal, the microwave source is used to receive and generate a second local oscillator signal and a third local oscillator signal based on the reference signal; the reference signal and the first local oscillator signal are phase synchronized.

[0059] A frequency synthesizer is a device that can produce a precise frequency output. It can generate very stable and accurate frequency signals and is suitable for applications that require high-precision frequency control. In this case, the frequency synthesizer is responsible for generating the first local oscillator signal, the second local oscillator signal, and the third local oscillator signal.

[0060] In another embodiment, the frequency output device includes a function generator and a microwave source. The function generator is used to generate a reference signal and a first local oscillator signal. The microwave source receives the reference signal generated by the function generator and generates a second local oscillator signal and a third local oscillator signal according to the reference signal.

[0061] Therefore, the use of a frequency synthesizer can provide a frequency output with very high accuracy and stability; by using a combination of a function generator and a microwave source, the system can flexibly adjust the output frequency to adapt to different measurement requirements and environmental conditions; the combination of a function generator and a microwave source ensures the synchronization and phase consistency between different local oscillator signals.

[0062] In some embodiments, the first local oscillator signal has the same frequency as the intermediate frequency signal; and / or the reference signal is a 10 MHz signal. The frequency of the first local oscillator signal is set to be the same as the frequency of the intermediate frequency signal to ensure that the IQ demodulator can effectively demodulate the intermediate frequency signal.

[0063] In some embodiments, the phased array chip to be tested is arranged on a translation platform, and the system further includes an off-axis parabolic mirror, which is arranged between the terahertz light source and the phased array chip to be tested, and is used to converge the terahertz wave to the target array element of the phased array chip to be tested.

[0064] It can be understood that the phased array chip to be tested is mounted on a translation stage. The translation stage can accurately control the position and movement of the chip, and it is crucial to adjust the direction and focus of the phased array chip. The vector measurement system also includes one or more off-axis parabolic mirrors, which are arranged between the terahertz light source and the phased array chip to be tested. The off-axis parabolic mirror is an optical element whose shape design allows it to reflect and focus the incident terahertz wave to a specific point, namely the target array element.

[0065] The terahertz waves generated by the terahertz light source are reflected and focused by the off-axis parabolic mirror and accurately converged onto the target array element of the phased array chip to be tested, ensuring that the energy of the terahertz wave is concentrated on a specific part of the chip, so that a single array element or a small part of the array elements can be accurately tested and analyzed.

[0066] Therefore, by using a translation stage and an off-axis parabolic mirror, the system can accurately control the focusing position of the terahertz wave and achieve precise testing of a single element of the phased array chip.

[0067] In some embodiments, the system further includes a beam splitter, which is disposed on an optical path between the phased array chip to be tested and the receiver, and is used to separate the terahertz signal from an unmodulated terahertz wave.

[0068] A beam splitter is an optical element that can split an incident light wave into two or more light beams, usually one of which is transmitted and one or more of which is reflected. In this case, the beam splitter is set on the optical path between the phased array chip to be tested and the receiver, so that the terahertz wave is refracted toward the phased array chip to be tested through the beam splitter, and the terahertz signal generated after the modulation of the phased array chip to be tested is transmitted through the beam splitter and then transmitted to the receiver. Other off-axis parabolic mirrors can also be set on the optical path after the terahertz signal is transmitted through the beam splitter to reflect the optical path, with the purpose of transmitting the terahertz signal to the receiver.

[0069] Because the beam splitter needs to be able to distinguish between the modulated signal and the original terahertz wave, it can ensure that they do not mix together and reach the receiver. Furthermore, the unmodulated terahertz waves are reflected or absorbed by the beam splitter, preventing them from continuing along the optical path to the receiver, thus preventing the unmodulated waves from interfering with the measurement results of the modulated signal.

[0070] Therefore, the use of a beam splitter can effectively separate the modulated signal from the unmodulated signal, thereby avoiding the interference of the unmodulated signal on the measurement result and improving the accuracy of the measurement. By ensuring that only the modulated signal is transmitted to the receiver, the beam splitter reduces the variables that may affect the measurement results, which helps to improve the stability of the system. Because the receiver only needs to process the modulated signal, rather than the modulated and unmodulated signals at the same time, the signal processing process is simplified. By blocking the unmodulated terahertz wave, the beam splitter helps to reduce background noise, thereby improving the signal-to-noise ratio and measurement reliability.

[0071] As an example, see Figure 1 , a vector measurement system is provided, including: a function generator (AFG), a microwave source (MS), a terahertz light source (T, Transmitter), a receiver (R, Receiver) and an IQ demodulator. The optical element includes an absorbing device composed of an absorbing material (Absorber), a beam splitter (Spliter) and an off-axis parabolic mirror (OAP).

[0072] The connecting lines in the figure show the signal path. The AFG contains two channels (channel 1 AFG-CH1 and channel 2 AFG-CH2). The channels are phase synchronized. Channel 1 generates a 10MHz signal as the reference signal of the MS, and channel 2 generates the first local oscillator signal S of the IQ demodulator according to the requirements. LOAFG; MS uses the 10MHz signal generated by AFG as a reference to generate two microwave signals, and channel 1 MS-CH1 is used as the second local oscillator signal S of the terahertz source RF , after being amplified by frequency doubling (frequency doubling factor is N1) and radiated through the speaker, channel 2MS-CH2 is used as the third local oscillator signal S of the receiver LO After passing through the built-in frequency multiplication amplification module (frequency multiplication factor is N2), it becomes the fourth local oscillator signal of the terahertz down-conversion mixer, and is mixed with the terahertz signal to generate the intermediate frequency signal S IF ; S LOAFG With S IF The demodulation is performed in the IQ demodulator to obtain an output signal, which is used to obtain the amplitude and phase information in the terahertz optical path. The optical path calibrates the performance of the terahertz phased array chip to be tested in a reflection manner. Figure 1 The solid arrow in the middle represents the unmodulated terahertz wave, and the dotted arrow represents the terahertz wave (terahertz signal) modulated by the phased array chip to be measured. The absorbing material (i.e., absorbing device) in the figure is used to absorb the unmodulated terahertz wave to prevent it from overlapping with the modulated signal and entering the receiver, affecting the measurement accuracy. The present application does not restrict the selection of absorbing materials. The absorbing material is a material that can absorb the incident electromagnetic wave energy and convert it into other forms of energy (such as heat energy), such as carbon materials, rubber-based composite materials, etc.

[0073] For ease of understanding, the terahertz vector measurement principle using the above vector measurement system is provided:

[0074] Assume that the MS generates two signals with different frequencies but initial phases of 0:

[0075]

[0076] Among them A RF ,ω RF , A LO ,ω LO They are the amplitude of channel 1 and frequency of channel 1, the amplitude of channel 2 and frequency of channel 2 of the MS. These two signals are multiplied by the transmitter and receiver respectively, and the multiplication coefficients are N1 and N2 respectively. Then the signal sent by the transmitter and the local oscillator terahertz signal of the receiver are:

[0077]

[0078] in are the amplitude and phase of the signal emitted by the terahertz light source and the amplitude and phase of the receiver local oscillator link. Figure 1 From the optical path, we know that S THzRF The signal will be modulated by the phased array chip to be tested, and after reflection, it will pass through the beam splitter to reach the receiver. The measured signal reaching the receiver is:

[0079]

[0080] where k MOD and are the amplitude modulation characteristics and phase modulation characteristics of the phased array chip to be tested for terahertz waves, k s and They are the amplitude attenuation and phase change caused by the optical path. After down-conversion by the receiver, the intermediate frequency signal is:

[0081]

[0082] The local oscillator signal of the IQ demodulator is generated by the AFG:

[0083]

[0084] in are the amplitude, frequency and phase of the IQ demodulator local oscillator signal generated by AFG. Then the output signal of the IQ demodulator is:

[0085]

[0086] where ω IF =N1ω RF -N2ω LO , When is the initial phase of the system, is a constant, k MOD =1 is the initial amplitude of the system, which is a constant. To facilitate data collection and processing, adjust ω LOAFG Make it with ω IF Equal, then S I and S Q is a DC signal, then:

[0087]

[0088] Then the amplitude modulation characteristics and phase modulation characteristics k of the phased array chip to be tested can be solved MOD and

[0089] As an example, the measurement optical path can be adjusted according to the actual test scenario. Figure 2 As shown in the figure, to test a single element of a phased array chip, OAP can be used to focus the terahertz light on the target element, and the phased array chip can be mounted on a two-dimensional translation stage for easy fine-tuning. The measurement principle is the same. To facilitate data collection and processing, ω can be set during measurement. LOAFG Make it with ω IF Equal, IQ demodulation can be performed correctly. IF =N1ω RF -N2ωLO , so ω RF and ω LO The number of decimal places of needs to be smaller than the number of decimal places of the MS decimal divider, that is, the minimum settable frequency step of the MS, and the ω generated by it IF The number of decimal places must be less than the minimum frequency step that can be set by the AFG. The frequency setting must meet the above conditions to complete the measurement.

[0090] In this application Figure 1 and Figure 2 In the figure, AFG is a function generator, MS is a microwave source, T is a terahertz light source, R is a receiver, and OAP is an off-axis parabolic mirror.

[0091] The system dynamic range is determined by the receiver sensitivity and the IQ demodulator dynamic range. Usually, the dynamic range of the IQ demodulator is small. Replacing the IQ demodulator according to different measurement powers can expand the system measurement dynamic range.

[0092] Method embodiment.

[0093] The embodiment of the present application provides a calibration method for a phased array chip of a vector measurement system based on the system embodiment. The specific implementation method is consistent with the implementation method and the technical effects achieved in the above-mentioned system implementation method, and some contents will not be repeated here.

[0094] See also Figure 7 , Figure 7 A schematic flow chart of a method for calibrating a phased array chip is shown. The method comprises:

[0095] S101, calibrating the vector measurement system;

[0096] S102, according to the actual measured frequency point, setting the output frequency and level of the first local oscillator signal of the frequency output device, and setting the output frequency and power of the second local oscillator signal and the third local oscillator signal;

[0097] S103, acquiring and processing the output signal of the IQ demodulator to obtain the amplitude modulation characteristics and phase modulation characteristics of the phased array chip to be tested.

[0098] Before S101, the step may further include selecting a specific test optical path of the vector measurement system according to actual test requirements.

[0099] In some embodiments, the calibrating the vector measurement system includes: performing displacement calibration and time stability calibration of the vector measurement system.

[0100] As an example, displacement calibration uses physical displacement to calibrate the phase measurement accuracy of the system. The phased array chip to be measured is installed on a precision displacement stage, and the displacement stage has a repeatability of 2 microns, which is a known quantity. The actual phase is calculated based on the measurement frequency and the displacement of the displacement stage, and multiple measurements are performed. When the phase error and amplitude fluctuation meet the requirements, the displacement calibration is considered to be completed, such as the maximum phase measurement error is less than 10°, the average error is less than 4°, and the amplitude fluctuation is less than 2dB. If this cannot be achieved, the optical path needs to be fine-tuned and realigned. The purpose of time stability calibration is to exclude the self-phase noise of the terahertz frequency multiplier used for frequency doubling amplification in the MS, AFG, and terahertz light source from affecting the measurement results. If the self-generated phase noise of the MS is too large, or the frequency drifts over time, the system measurement accuracy will be reduced. Therefore, it is often defined that when the phase drift is less than 1° / min, the system calibration is considered to be completed. If this condition cannot be met, the test environment temperature needs to be stabilized or low phase noise equipment needs to be replaced.

[0101] According to the actual measurement frequency, set the output frequency and level of the two channels of AFG, and set the output frequency and power of the two channels of MS. Control the phased array chip according to the measurement requirements, and control the acquisition equipment to collect and process the output signal of the IQ demodulator to obtain the amplitude modulation characteristics and phase modulation characteristics of the phased array chip.

[0102] A test example with a frequency of 317 GHz is provided, as follows:

[0103] choose Figure 1 The optical path shown is used to test the overall performance of the terahertz phased array chip.

[0104] After adjusting the optical path, displacement calibration is performed. The chip under test is mounted on the displacement stage of the stepper motor. The stepper motor moves 10 microns to the right each time, and the output signal of the IQ demodulator is collected. The results are as follows: Figure 3 and Figure 4 As shown in the figure, it can be seen that the maximum error of phase measurement is less than 7°, the average error is less than 2°, and the amplitude fluctuation is less than 1.6dB, thus meeting the measurement requirements.

[0105] After the displacement calibration, the time stability calibration is performed. The IQ demodulator output signal is collected without any operation. The results are as follows: Figure 5 As shown, the total phase drift of the 20mmin system is 7°, which is about 0.35° / mmin. Since the single data acquisition time is less than 1mmin, it meets the measurement requirements.

[0106] The calibration is now complete and the chip is tested. The measurement frequency is 317 GHz and the preset fI F =50MHz. In this experiment, the transmitter frequency multiplication factor N1 is 27, and the receiver frequency multiplication factor is 24, so fL O =13.21GHz, f RF=11.743GHz, then the actual intermediate frequency is f IF =21MHz. Therefore, the frequency of AFG channel 2 is set to 21 MHz. The signal modulation capability of the phased array chip is measured at this frequency. The bias range of the phased array chip is set to 0-6V with a step size of 0.2V. The measurement results are as follows: Figure 6 As shown, the amplitude and phase modulation performance of the chip is demonstrated.

[0107] Obviously, according to the above-mentioned vector measurement system for phased array chip calibration, and the calibration method of phased array chip, it can be known that the technical solution provided by the present application uses a beam splitter to separate the incident light beam and the reflected light path in the terahertz optical path to complete the calibration of the reflective phased array chip. An absorbing device is added to the optical path to absorb unmodulated terahertz light to prevent the unmodulated terahertz wave from mixing with the terahertz signal into the receiver. In the RF link part, AFG is used to generate the reference signal of the MS and the local oscillator signal of the IQ demodulator. Because AFG has extremely low phase noise, the local oscillator signal of the IQ demodulator has very small phase noise and is synchronized with the intermediate frequency signal frequency, so it has extremely high measurement accuracy.

[0108] Compared with the measurement method using VNA:

[0109] Higher measurement frequency: This application can use a combination of different terahertz transmitters and receivers to easily achieve higher frequency measurements with higher accuracy.

[0110] Calibration error: This application adopts the optical path calibration method, and the system error is smaller.

[0111] Dynamic range: This application can replace the receiver and IQ demodulator with appropriate dynamic range according to the measurement requirements to achieve a larger measurement dynamic range.

[0112] Measurement accuracy: The measurement accuracy of this application is mainly determined by the phase noise level of AFG, MS and terahertz frequency multiplier, and is not affected by the link. Therefore, the measurement accuracy is higher than that of VNA.

[0113] Compared to the published superheterodyne measurement link:

[0114] Simple link: The signal link of this application is simpler, requires fewer components, has strong resistance to external interference, and has high stability.

[0115] Measurement accuracy: In the terahertz optical path, the present application suppresses interference signals to the maximum extent, and the IQ demodulator uses the signal generated by the AFG as the local oscillator, which has lower phase noise and therefore has higher measurement accuracy.

[0116] Device Embodiments.

[0117] The embodiment of the present application provides an electronic device, the specific implementation of which is consistent with the implementation and technical effects recorded in the above method and system implementation, and some contents are not repeated. The electronic device includes one or more processors and a memory; one or more programs are stored in the memory and configured to be executed by the one or more processors to perform any of the above methods.

[0118] See also Figure 8 , Figure 8 It is a structural schematic diagram of an electronic device provided in an embodiment of the present application.

[0119] The electronic device may include, for example, at least one memory 11, at least one processor 12, and a bus 13 connecting different platform systems.

[0120] The memory 11 may include a readable medium in the form of a volatile memory, such as a random access memory (RAM) 111 and / or a cache memory 112 , and may further include a read-only memory (ROM) 113 .

[0121] The memory 11 also stores a computer program, which can be executed by the processor 12 so that the processor 12 implements the steps of any of the above methods.

[0122] The memory 11 may also include a utility 114 having at least one program module 115, such program module 115 including but not limited to: an operating system, one or more application programs, other program modules and program data, each of which or some combination may include the implementation of a network environment.

[0123] Accordingly, the processor 12 may execute the above-mentioned computer program, and may execute the utility 114 .

[0124] The processor 12 may adopt one or more application specific integrated circuits (ASICs), DSPs, programmable logic devices (PLDs), complex programmable logic devices (CPLDs), field programmable gate arrays (FPGAs), or other electronic components.

[0125] Bus 13 may represent one or more of several types of bus structures, including a memory bus or memory controller, a peripheral bus, an accelerated graphics port, a processor or a local bus using any of a variety of bus architectures.

[0126] The electronic device may also communicate with one or more external devices 14 such as a keyboard, a pointing device, a Bluetooth device, etc., and may also communicate with one or more devices that can interact with the electronic device, and / or communicate with any device (such as a router, a modem, etc.) that enables the electronic device to communicate with one or more other computing devices. Such communication may be performed through an input / output interface 15. In addition, the electronic device may also communicate with one or more networks (such as a local area network (LAN), a wide area network (WAN) and / or a public network, such as the Internet) through a network adapter 16. The network adapter 16 may communicate with other modules of the electronic device through the bus 13. It should be understood that, although not shown in the figure, other hardware and / or software modules may be used in conjunction with the electronic device in actual applications, including but not limited to: microcode, device drivers, redundant processors, external disk drive arrays, RAID systems, tape drives, and data backup storage platforms.

[0127] Storage Medium Embodiments.

[0128] The embodiment of the present application also provides a computer-readable storage medium, and its specific embodiment is consistent with the embodiment recorded in the above method embodiment and the technical effects achieved, and some contents will not be repeated here.

[0129] The computer-readable storage medium stores a computer program, and when the computer program is executed by at least one processor, the steps of any of the above methods or the functions of any of the above electronic devices are implemented.

[0130] Computer readable medium can be a computer readable signal medium or a computer readable storage medium. In an embodiment of the present application, a computer readable storage medium can be any tangible medium containing or storing a program, which can be used by an instruction execution system, device or device or used in combination with it. Computer readable storage medium can be, for example, but not limited to, a system, device or device of electricity, magnetism, light, electromagnetic, infrared, or semiconductor, or any combination of the above. More specific examples (non-exhaustive list) of computer readable storage medium include: an electrical connection with one or more wires, a portable disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above.

[0131] The computer-readable storage medium may include a data signal propagated in a baseband or as part of a carrier wave, wherein a readable program code is carried. Such propagated data signals may take a variety of forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. The computer-readable storage medium may also be any computer-readable medium that can send, propagate, or transmit a program for use by an instruction execution system, an apparatus, or a device or for use in combination with it. The program code contained on the computer-readable storage medium may be transmitted using any appropriate medium, including but not limited to wireless, wired, optical cable, RF, etc., or any suitable combination of the above. The program code for performing the operation of the present invention may be written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Java, C++, etc., and also conventional procedural programming languages ​​such as C language or similar programming languages. The program code may be executed entirely on a user computing device, partially on a user device, as an independent software package, partially on a user computing device, partially on a remote computing device, or entirely on a remote computing device or server. Where a remote computing device is involved, the remote computing device may be connected to the user computing device through any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computing device (e.g., through the Internet using an Internet service provider).

[0132] Program Product Embodiments.

[0133] The embodiment of the present application further provides a program product embodiment, wherein the computer program product includes a computer program, and when the computer program is executed by at least one processor, the steps of any one of the methods in the method embodiments are implemented.

[0134] It should be noted that, in the embodiments of the present application, "at least one" refers to one or more, and "plurality" refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone, where A and B can be singular or plural. The character " / " generally indicates that the objects associated before and after are in an "or" relationship. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, at least one of a, b or c can represent: a, b, c, a and b, a and c, b and c or a and b and c, where a, b and c can be single or multiple. It is worth noting that "at least one" can also be interpreted as "one or more items".

[0135] The terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are configured to distinguish similar objects, and do not have to be configured to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0136] This application is explained from the perspectives of purpose of use, effectiveness, progress and novelty, and has met the functional enhancement and usage requirements emphasized by the Patent Law. The above description and drawings of this application are only the preferred embodiments of this application, and are not intended to limit this application. Therefore, all structures, devices, features, etc. that are similar or identical to this application, that is, all equivalent replacements or modifications made in accordance with the scope of the patent application of this application, should fall within the scope of protection of the patent application of this application.

Claims

1. A vector measurement system for phased array chip calibration, characterized in that: The system comprises: A frequency output device, the frequency output device is used to generate a first local oscillation signal, a second local oscillation signal and a third local oscillation signal; A terahertz light source, the terahertz light source is used to receive the second local oscillation signal and radiate terahertz waves after frequency doubling and amplification, and the terahertz waves are used to generate terahertz signals after being modulated by the phased array chip to be tested; A receiver, the receiver is used to receive the third local oscillator signal and the terahertz signal, the third local oscillator signal is used as a fourth local oscillator signal after frequency doubling and amplification, the fourth local oscillator signal is mixed with the terahertz signal to generate an intermediate frequency signal and output it; An IQ demodulator, the IQ demodulator is used to receive the intermediate frequency signal and the first local oscillator signal and perform demodulation to obtain an output signal, and the output signal is used to obtain the amplitude modulation characteristics and phase modulation characteristics of the phased array chip to be tested; A wave absorbing device is arranged between the receiver and the terahertz light source, and is used to prevent unmodulated terahertz waves from overlapping with the terahertz signal and entering the receiver.

2. The vector measurement system according to claim 1, characterized in that: The frequency output device is a frequency synthesizer; or, the frequency output device includes a function generator and a microwave source, the function generator is used to generate a reference signal and a first local oscillator signal, and the microwave source is used to receive and generate a second local oscillator signal and a third local oscillator signal based on the reference signal; the reference signal and the first local oscillator signal are phase synchronized.

3. The vector measurement system according to claim 2, characterized in that: The first local oscillator signal has the same frequency as the intermediate frequency signal; and / or the reference signal is a 10 MHz signal.

4. The vector measurement system according to claim 1, characterized in that: The phased array chip to be tested is arranged on a translation platform, and the system also includes an off-axis parabolic mirror, which is arranged between the terahertz light source and the phased array chip to be tested, and is used to converge the terahertz wave to the target array element of the phased array chip to be tested; and / or, the terahertz light source is used to receive the second local oscillator signal and radiate the terahertz wave through a speaker after frequency doubling and amplification.

5. The vector measurement system according to claim 1, characterized in that: The system further comprises a beam splitter, which is arranged on an optical path between the phased array chip to be tested and the receiver, and is used for separating the terahertz signal from an unmodulated terahertz wave.

6. A calibration method for a phased array chip of a vector measurement system according to any one of claims 1 to 5, characterized in that: The method comprises: performing calibration of the vector measurement system; According to the actual measured frequency point, the output frequency and level of the first local oscillator signal of the frequency output device are set, and the output frequency and power of the second local oscillator signal and the third local oscillator signal are set; The output signal of the IQ demodulator is acquired and processed to obtain the amplitude modulation characteristics and phase modulation characteristics of the phased array chip to be tested.

7. The calibration method according to claim 6, characterized in that: The calibrating of the vector measurement system includes: performing displacement calibration and time stability calibration of the vector measurement system.

8. An electronic device, characterized in that: The method comprises one or more processors and a memory; one or more programs are stored in the memory and are configured so that the one or more processors execute the method according to any one of claims 6 to 7.

9. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by at least one processor, the steps of the method according to any one of claims 6 to 7 are implemented.

10. A computer program product, characterized in that The computer program product comprises a computer program, and when the computer program is executed by at least one processor, the steps of the method according to any one of claims 6 to 7 are implemented.

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