Thermal vacuum test system for Ka phased-array antenna

Abstract

The invention relates to the field of antenna testing, and discloses a thermal vacuum test system for a Ka phased-array antenna, and the system comprises a vacuum cabin; the test tool is used for bearing the phased-array antenna to be tested; the multi-scale power injection array is arranged in the vacuum cabin body and is used for injecting controllable microwave energy into the phased-array antenna to be tested in a non-contact manner so as to simulate a dynamic thermal load in the phased-array antenna to be tested; the sparse holographic measurement array is mounted in the vacuum cabin, statically arranged in a radiation near-field region of the phased-array antenna to be measured and used for instantaneously collecting an electromagnetic wave field sparse sample emitted by the phased-array antenna to be measured; and the cooperative control and data processing center is respectively connected with the multi-scale power injection array and the sparse holographic measurement array. By arranging the multi-scale power injection array, not only can slow-varying reference thermal load under a mission profile be simulated, but also rapid energy disturbance can be superposed in a specific area, so that high-fidelity simulation of an antenna in an in-orbit complex thermal environment is realized.

Description

TECHNICAL FIELD

[0001] The application relates to the field of antenna testing, and particularly relates to a Ka phased array antenna thermal vacuum test system. BACKGROUND

[0002] Phased array antennas, especially Ka-band phased array antennas deployed on satellite platforms, are key components of modern communication, remote sensing and navigation systems. The radio frequency performance of such antennas, such as antenna gain, beam pointing accuracy and sidelobe level, shows high sensitivity to operating temperature and temperature gradient inside the structure. During on-orbit operation, the antenna will be subjected to extreme temperature cycles caused by the alternation of direct solar irradiation and deep space background, and the power consumption changes of the active transmit-receive (T / R) components inside the antenna under different operating modes will also produce dynamic and non-uniform temperature distribution on the antenna aperture. Therefore, it is necessary to conduct thermal vacuum tests on the ground to comprehensively and accurately verify the on-orbit performance and operational reliability of the antenna before satellite launch.

[0003] In the thermal vacuum test of a phased array antenna, a core technical challenge lies in how to realistically reproduce the complex dynamic thermal load that the antenna is subjected to during on-orbit operation. Currently, the main technical means for simulating external heat flow include contact heaters and non-contact infrared lamp arrays.

[0004] The method using contact heating fins (such as resistive thin-film heaters) requires that the heating elements be directly pasted on the surface of the antenna to be tested. This method has several inherent defects. Firstly, the pasting of the heating fins changes the original thermal characteristics of the antenna surface, introducing additional heat capacity and heat transfer paths, thereby interfering with the accuracy of the test results. Secondly, the physical size and wiring of the heating fins limit their spatial resolution, making it difficult to generate a fine, non-uniform thermal map consistent with the actual power consumption distribution. Thirdly, the response speed of resistive heating elements is slow, and their thermal inertia makes them unable to simulate rapid changes in thermal shock, failing to meet the requirements for examining transient effects.

[0005] The use of non-contact infrared lamp arrays to some extent avoids the pollution problem of the contact method, but its simulation fidelity still has significant limitations. Conventional infrared lamp arrays are mainly used to provide a large-area, uniform or slowly varying background thermal environment, and their optical systems and control methods are difficult to achieve precise "sculpting" of energy on specific areas, and cannot form complex, high-gradient non-uniform thermal load distribution. More critically, the thermal inertia of the infrared filament is extremely large, and the response time of its opening and closing is usually on the order of seconds, completely unable to meet the requirement of injecting a rapid energy pulse with a duration of milliseconds or even microseconds at a specific location.

[0006] Therefore, the existing thermal vacuum test method cannot simultaneously simulate the slow-varying reference thermal load experienced by the phased array antenna, which is determined by the mission profile, and the fast-varying local energy disturbance caused by a specific working mode switching or external environment mutation in a non-contact and high-fidelity manner in one test. This makes it impossible to effectively synchronize the test and distinguish the physical mechanisms of the thermal deformation accumulation effect of the antenna structure and the junction temperature transient effect of the active device with different time scales. SUMMARY

[0007] In view of the deficiencies of the prior art, the present application provides a Ka phased array antenna thermal vacuum test system, which solves the problem that the prior art method cannot simultaneously reproduce the slow-varying non-uniform reference thermal load and the fast-varying local energy disturbance experienced by the phased array antenna in a non-contact and high-fidelity manner in one test, and thus cannot effectively distinguish and diagnose the performance degradation mechanisms caused by thermal effects with different time scales.

[0008] To achieve the above object, the present application is implemented by the following technical solution: a Ka phased array antenna thermal vacuum test system, comprising: a vacuum chamber body; a test tool for carrying the phased array antenna to be tested; a multi-scale power injection array installed in the vacuum chamber body for injecting controllable microwave energy to the phased array antenna to be tested in a non-contact manner to simulate the dynamic thermal load inside the phased array antenna to be tested; a sparse holographic measurement array installed in the vacuum chamber body and statically arranged in the radiation near-field region of the phased array antenna to be tested for instantaneously collecting sparse samples of the electromagnetic wave field emitted by the phased array antenna to be tested; a cooperative control and data processing center connected with the multi-scale power injection array and the sparse holographic measurement array for cooperatively controlling the injection timing of the microwave energy and the collection timing of the sparse samples of the electromagnetic wave field, and reconstructing the far-field pattern of the phased array antenna to be tested according to the sparse sample data of the electromagnetic wave field.

[0009] According to the above technical solution: by providing a multi-scale power injection array, a non-uniform thermal load distribution highly consistent with the actual working state can be formed on the surface of the phased array antenna to be tested in a non-contact manner. The array realizes multi-scale simulation of the thermal load in the spatial and temporal dimensions by radiating controllable microwave energy to the antenna to be tested and relying on its independent high-speed electric control capability of each radiation unit. This solves the problem that the prior art cannot simultaneously examine and effectively distinguish and diagnose the performance degradation caused by different physical mechanisms in one test, greatly improving the accuracy and comprehensiveness of the ground thermal vacuum test of the phased array antenna.

[0010] Preferably, the multi-scale power injection array injects microwave energy with a frequency set to be absorbed by the T / R module inside the phased array antenna under test and converted into heat energy.

[0011] Preferably, the dynamic thermal loading generated by the multi-scale power injection array includes: a slowly varying reference thermal loading with a spatially and temporally slowly varying power density to simulate the reference thermal distribution of the phased array antenna under test under a specific mission profile; a fast varying energy perturbation which is a localized energy pulse in both time and space superimposed on the slowly varying reference thermal loading.

[0012] Preferably, the sparse holographic measurement array is composed of multiple fixed wide-beam probes without any mechanical moving parts, which are arranged in a non-uniform sparse manner.

[0013] Preferably, the collaborative control and data processing center is configured to reconstruct the complete electric field distribution on the aperture plane of the phased array antenna under test from the sparse sample data of the electromagnetic wave field by solving underdetermined equations based on the compressed sensing theory, and further calculate the far-field pattern through near-field to far-field transformation.

[0014] Preferably, the collaborative control and data processing center is configured to instruct the sparse holographic measurement array to perform continuous acquisition with high temporal resolution to capture the transient radio frequency response of the phased array antenna under test caused by the fast varying energy perturbation within the time window of the fast varying energy perturbation injected by the multi-scale power injection array.

[0015] Preferably, the collaborative control and data processing center is further configured to extract key performance indicators from the reconstructed far-field pattern and perform correlation analysis on the time evolution of the key performance indicators and the injected dynamic thermal loading to diagnose the physical mechanism causing the performance change of the phased array antenna under test.

[0016] Preferably, the correlation analysis includes: analyzing thermal-mechanical effects based on the response of the key performance indicators to the slowly varying reference thermal loading; analyzing device-level thermoelectric effects based on the response of the key performance indicators to the fast varying energy perturbation.

[0017] Preferably, the multi-scale power injection array is a phased array antenna, and the collaborative control and data processing center controls the excitation amplitude and phase of each element of the phased array antenna to form a preset spatio-temporal power density distribution on the surface of the phased array antenna under test.

[0018] A Ka-band phased array antenna thermal vacuum test method, comprising the following steps: placing the phased array antenna under test in a vacuum cryogenic environment; The microwave energy is injected to the phased array antenna to be tested in a non-contact manner through a multi-scale power injection array, so as to generate a dynamic thermal load in the phased array antenna, and the dynamic thermal load comprises a slowly varying reference thermal load and a fast varying energy disturbance superimposed on the slowly varying reference thermal load; While the microwave energy is injected, sparse samples of an electromagnetic wave field emitted by the phased array antenna to be tested are instantaneously collected through a fixed sparse holographic measurement array; Based on the collected sparse samples of the electromagnetic wave field, a transient far-field pattern sequence of the phased array antenna to be tested is reconstructed through a computational imaging algorithm; Changes in performance indicators in the far-field pattern sequence are analyzed in association with the generated dynamic thermal load, so as to diagnose thermal and electrical coupling characteristics of the phased array antenna to be tested.

[0019] The application provides a Ka phased array antenna thermal vacuum test system. 1、The application can form a non-uniform thermal load distribution highly consistent with a real working state on the surface of the phased array antenna to be tested in a non-contact manner through the multi-scale power injection array, the array can not only simulate a slowly varying reference thermal load under a task profile, but also superimpose a fast energy disturbance on a specific region, so that high-fidelity simulation of a complex thermal environment of the antenna in orbit is realized.

[0020] 2、The application replaces a traditional mechanical scanning near-field measurement by adopting a static sparse holographic measurement array and combining a computational imaging algorithm based on compressed sensing, so that a holographic snapshot of the entire radiation field can be completed in a microsecond level time without any mechanical movement, and high time resolution continuous monitoring of the radio frequency performance of the antenna is realized.

[0021] 3、The application realizes unified and cooperative control of the multi-scale power injection array and the sparse holographic measurement array through the cooperative control and data processing center, and integrates a thermal excitation and a radio frequency measurement link separated in a traditional test into an automatic test process defined by software. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 The figure is a system module architecture diagram of the application; Figure 2 The figure is a step logic judgment schematic diagram of the application; Figure 3 The figure is a step schematic diagram of the application; Figure 4 The figure is a cabin physical structure schematic diagram of the application; Figure 5 Physical structure diagram of the cooperative control and data processing center of the application. DETAILED DESCRIPTION

[0023] The technical solutions of the application will be described clearly and completely below with reference to the drawings of the application. Obviously, the described embodiments are only some of the embodiments of the application, but not all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the application.

[0024] Please refer to the drawings of the application Figure 1 - the drawings of the application Figure 5 The embodiment of the application provides a Ka phased array antenna thermal vacuum test system, which comprises: a vacuum cabin body; a test tool for carrying a phased array antenna to be tested; a multi-scale power injection array installed in the vacuum cabin body, used to inject controllable microwave energy to the phased array antenna to be tested in a non-contact manner, so as to simulate the dynamic thermal load inside the phased array antenna to be tested; the frequency of the microwave energy injected by the multi-scale power injection array is set to be absorbed by the T / R component inside the phased array antenna to be tested and converted into thermal energy. The dynamic thermal load generated by the multi-scale power injection array comprises: a slowly varying reference thermal load, whose power density slowly varies in space and time, used to simulate the reference thermal distribution of the phased array antenna to be tested under a specific mission profile; a fast-varying energy disturbance, which is an energy pulse superimposed on the slowly varying reference thermal load and is local in time and space. The multi-scale power injection array forms a preset spatiotemporal power density distribution on the surface of the phased array antenna to be tested by controlling the excitation amplitude and phase of each array element of the phased array antenna, the cooperative control and data processing center.

[0025] a sparse holographic measurement array installed in the vacuum cabin body and statically arranged in the radiation near-field region of the phased array antenna to be tested, used to instantaneously collect sparse samples of the electromagnetic wave field emitted by the phased array antenna to be tested; the sparse holographic measurement array is composed of a plurality of fixed wide-beam probes without any mechanical moving parts, and the probes are arranged in a non-uniform sparse manner.

[0026] The cooperative control and data processing center is connected with the multi-scale power injection array and the sparse holographic measurement array respectively, and is used for cooperatively controlling the injection timing of microwave energy and the acquisition timing of the electromagnetic wave field sparse sample, and reconstructing the far-field pattern of the phased array antenna to be tested according to the electromagnetic wave field sparse sample data. The cooperative control and data processing center is configured to reconstruct the complete electric field distribution of the aperture plane of the phased array antenna to be tested from the electromagnetic wave field sparse sample data by solving an underdetermined equation based on the compressed sensing theory, and further calculate the far-field pattern by near-field to far-field transformation.

[0027] The cooperative control and data processing center is configured to instruct the sparse holographic measurement array to continuously acquire at a high time resolution within a time window in which the multi-scale power injection array injects fast-varying energy disturbance, so as to capture the transient radio frequency response of the phased array antenna to be tested caused by the fast-varying energy disturbance. The cooperative control and data processing center is also configured to extract key performance indicators in the reconstructed far-field pattern, and perform correlation analysis on the time evolution of the key performance indicators and the injected dynamic thermal load, so as to diagnose the physical mechanism causing the performance change of the phased array antenna to be tested. The correlation analysis includes: analyzing the thermal mechanical effect based on the response of the key performance indicators to the slow-varying reference thermal load; analyzing the device-level thermoelectric effect based on the response of the key performance indicators to the fast-varying energy disturbance.

[0028] Specifically, the application includes a vacuum chamber, a multi-scale power injection array, a sparse holographic measurement array, a cooperative control and data processing center, and a test tool for carrying the phased array antenna to be tested in terms of physical structure.

[0029] The vacuum chamber, the multi-scale power injection array, the sparse holographic measurement array, and the test tool are all connected with the vacuum chamber; the multi-scale power injection array and the sparse holographic measurement array are arranged on the two sides of the phased array antenna to be tested respectively, and are both connected with the cooperative control and data processing center for signal connection and data communication; the vacuum chamber is composed of a vacuum pump set and a liquid nitrogen cold plate. The vacuum pump set is used to pump the inside of the vacuum chamber to a specified vacuum degree, which can be preferably less than 10 -3 Pascals; the liquid nitrogen cold plate covers the inner wall of the vacuum chamber, and is used to provide a stable deep space low temperature background environment, which can be preferably about 77K background temperature.

[0030] The multi-scale power injection array is a two-dimensional planar phased array antenna, whose array plane is composed of a large number of microwave radiation units, which can be preferably microstrip patch antenna units. The working frequency of the array is set to a frequency band that can be effectively absorbed by the semiconductor materials and lossy media in the T / R components inside the phased array antenna under test and mainly converted into heat energy, rather than the working communication frequency band of the phased array antenna under test. The coordinated control and data processing center provides independent excitation amplitude and phase control signals to each radiation unit of the array, thereby forming a specific spatio-temporal distribution of power density on the aperture plane of the phased array antenna under test.

[0031] The sparse holographic measurement array is a two-dimensional planar array composed of multiple static fixed wide-beam probes, which can be preferably helical antennas or dipole antennas. These probes are arranged in a non-uniform sparse pattern on the measurement plane, and the overall structure does not contain any mechanical moving parts; the array is arranged in the radiation near-field region of the phased array antenna under test for synchronous acquisition of sparse samples of the electromagnetic wave field radiated by the phased array antenna under test in space at any time, and the acquired complex voltage signals are transmitted to the coordinated control and data processing center.

[0032] The coordinated control and data processing center includes a host computer, a real-time controller, a high-performance computing unit, and a data acquisition and storage system in hardware. The real-time controller, which can be preferably a field programmable gate array, is used to generate high-precision clock synchronization signals and control instructions, which are respectively sent to the multi-scale power injection array and the sparse holographic measurement array; the high-performance computing unit, which can be preferably a graphics processor server, is used to execute subsequent electromagnetic field reconstruction algorithms; the data acquisition and storage system is used to receive and save a large amount of measurement data transmitted from the sparse holographic measurement array.

[0033] In a specific embodiment, the complete flow of the test method is as follows: First, the test preparation and system calibration are performed, the phased array antenna under test is installed on the test tool and placed at the predetermined position in the vacuum chamber, the vacuum chamber is started, the chamber is pumped to the specified vacuum degree, the liquid nitrogen cold plate is turned on, and after the background temperature is stabilized, the system calibration is performed. The calibration process includes calibrating the positions and response characteristics of the probes in the sparse holographic measurement array, and obtaining the system sensing matrix connecting the aperture plane of the phased array antenna under test and the measurement plane of the sparse holographic measurement array by electromagnetic simulation or actual measurement method.

[0034] Secondly, the dynamic thermal load is generated and injected. According to a preset mission profile of the simulation antenna in orbit, the reference thermal load distribution on the aperture plane of the phased array antenna to be tested is calculated first. Then, the excitation amplitude and phase of each array element in the multi-scale power injection array are controlled to form the reference thermal load on the surface of the phased array antenna to be tested. During the stable application of the reference thermal load, the multi-scale power injection array is controlled to inject one or more fast-varying energy disturbances at specific times and positions according to the preset test script.

[0035] Thirdly, the electromagnetic field is synchronously collected at high time resolution. During the whole process of dynamic thermal load injection, especially before and after the time window of injecting fast-varying energy disturbances, the sparse holographic measurement array is instructed to collect electromagnetic wave field sparse samples at high time resolution. The time interval between two holographic snapshots is set to be able to capture the characteristic time scale of the transient radio frequency response caused by the fast-varying energy disturbance, which can be preferably in the order of microseconds or milliseconds.

[0036] Then, the transient electromagnetic field is reconstructed and calculated. The large amount of time series data collected by the sparse holographic measurement array is received and processed by the collaborative control and data processing center. For the electromagnetic wave field sparse sample data at each collection time, the complete electric field distribution on the aperture plane of the phased array antenna to be tested at that time is reconstructed by using the compressive sensing-based computational imaging algorithm, and then the far-field pattern at that time is calculated by using the near-field to far-field transformation algorithm, thereby generating a dynamic far-field pattern sequence that can fully represent the evolution of the antenna performance over time.

[0037] Finally, the multi-scale time series correlation diagnosis is performed. From the generated dynamic far-field pattern sequence, the curves of the key performance indicators changing over time are extracted. By aligning and comparing these curves with the injected dynamic thermal load in time, the correlation between them is analyzed, thereby distinguishing and diagnosing different physical mechanisms that cause the degradation of the antenna performance.

[0038] During the generation of the dynamic thermal load, the reference thermal load P buse (r',t) is generated based on the inversion of the antenna mission profile. First, the power consumption of each T / R component is calculated according to the antenna design parameters and the beam pointing function, and then it is mapped to the continuous power density distribution on the aperture plane S ap (r',t). The fast-varying energy disturbance P pert (r',t) is designed as a local pulse in space and time, and its mathematical form can be expressed as: P pert (r',t) = A p• g(r' - r'0) • h(t - t0) where A p is the peak power density of the perturbation pulse, g(·) is a spatial distribution function, which can be preferably a two-dimensional Gaussian function, used to focus the energy to a region centered at r'0, h(·) is a time envelope function, which can be preferably a square pulse, used to apply an energy pulse with a short duration at t0.

[0039] In the transient electromagnetic field reconstruction process, the core is to solve a convex optimization problem with L1 norm regularization. The aperture field of the phased array antenna to be measured has sparse characteristics in a certain transform domain, which can be preferably in the spherical wave expansion or wavelet transform domain. Let the aperture field vector x(t) be transformed to the sparse domain by the sparse basis matrix Ψ to obtain the sparse coefficient vector α(t).

[0040] The reconstruction process is to solve the following equation to obtain the optimal estimate of the sparse coefficient vector where y(t) is the measurement vector, A is the system sensing matrix, and λ is a regularization parameter used to balance the consistency between the reconstruction result and the measurement data and the sparsity of the solution.

[0041] This optimization problem can be efficiently solved by fast iterative shrinkage thresholding algorithm, etc. After that, the high-resolution aperture field can be reconstructed by .

[0042] In the multi-scale time series correlation diagnosis process, first, the time evolution curves of key performance indicators are extracted from the far-field pattern sequence E ff (θ, φ, t), which can be preferably the peak gain K guin (t), the beam pointing error K p.e. (t), the peak sidelobe level K psll (t), etc.

[0043] Subsequently, these key performance indicator curves are analyzed. Among them, the macroscopic drift and change trend on the key performance indicator curve with a long time scale (seconds to minutes) is correlated with the change curve of the slow-varying reference thermal load P base , which is used to analyze the influence caused by cumulative thermal-mechanical effects such as material thermal expansion and structural deformation. At the same time, the transient response characteristics appearing on the key performance indicator curve before and after the time t0 when the fast-varying energy perturbation P pert is applied, which can be preferably the peak deviation, response delay, recovery time, etc., are analyzed, which is used to analyze the influence caused by rapid device-level thermal-electric effects such as T / R component internal semiconductor junction temperature transient.

[0044] In the present invention, the precise timing synchronization between the energy injection action of the multiscale power injection array and the field sample collection action of the sparse holographic measurement array is guaranteed by a real-time controller in the cooperative control and data processing center, which can be preferably a field programmable gate array. The real-time controller generates a high-stability master clock signal and distributes it to the control units of the multiscale power injection array and the data collection units of the sparse holographic measurement array to establish a unified system time reference.

[0045] In the test execution phase, the host computer loads a test sequence containing a series of instructions with precise time stamps into the real-time controller, which specifies the execution of specific hardware operations at specific time points.

[0046] At time t start_p The multiscale power injection array is instructed to start injecting fast-varying energy perturbations at time t end_p and end the injection; at the same time, the sparse holographic measurement array is instructed to continuously trigger data collection at time t start_m to t end_m with an extremely short time interval Δt m .

[0047] The real-time controller generates hardware trigger signals directly at corresponding clock cycles according to these time stamps, thereby achieving precise synchronization between the excitation action of the multiscale power injection array and the measurement action of the sparse holographic measurement array on the microsecond time scale.

[0048] The system of the present invention integrates the entire test process, including environment establishment, system calibration, multiscale thermal load injection, synchronous radio frequency field collection, data processing and analysis, and all other links into an automated test process that can be defined by software. Before the test begins, the operator configures or loads a complete automated test script according to the test requirements. The script defines the parameters of the entire test process, which can be preferably the target vacuum degree and temperature, the time-space distribution function of the slow-varying reference thermal load, the injection time, position, peak power and duration of one or more fast-varying energy perturbations, and the collection rate and total duration of the sparse holographic measurement array.

[0049] After the test is started, the collaborative control and data processing center automatically analyzes the script and autonomously completes all operations. The control vacuum pump group and the liquid nitrogen cold plate build the test environment, execute the system calibration program, and accurately control the multi-scale power injection array and the sparse holographic measurement array to work collaboratively according to the time sequence defined in the script. During the entire process, the operator only needs to monitor the system state without any manual intervention. This automation of the execution of the preset script from manual coordination and physical switching fundamentally eliminates the risk of test interruption and uncertainty caused by untimely operation or personnel coordination failure, ensures the continuity and repeatability of the test process, and reduces the traditional double or multiple post requirements to a single monitoring post.

[0050] In the following, a specific application example will be used to more fully describe the technical solutions of the present application. The example is intended to illustrate how the present application is applied to a specific Ka phased array antenna and obtain quantifiable diagnostic results.

[0051] The example is intended to test and diagnose the dynamic thermal and electrical coupling characteristics of a Ka-band satellite-borne transmitting phased array antenna in a thermal vacuum environment.

[0052] The example is intended to test and diagnose the dynamic thermal and electrical coupling characteristics of a Ka-band satellite-borne transmitting phased array antenna in a thermal vacuum environment. The working frequency of the phased array antenna to be tested is 30.0 GHz, the array size is 256 units, the layout is 16x16, and the aperture size is 15 cmx15 cm.

[0053] To perform this test, the vacuum chamber is set to a vacuum degree of 1.0x10 -5 Pa in the vacuum chamber, and the background temperature is maintained at 77K by the liquid nitrogen cold plate.

[0054] The working frequency of the multi-scale power injection array is set to 24.0 GHz to ensure that the energy is effectively absorbed by the T / R components of the antenna to be tested.

[0055] The sparse holographic measurement array is configured with 300 wide-beam spiral antennas, and the data acquisition rate is set to 100kS / s, i.e., a holographic snapshot is taken every 10 microseconds.

[0056] During the test, a preset automated test script is started. During the period from the start of the test to 1800 seconds, the multi-scale power injection array injects a slowly varying reference thermal load onto the surface of the antenna to be tested. The load is intended to simulate the power consumption distribution of the antenna when performing a ground scanning task. The total power increases linearly with time, and finally reaches a steady state at 1800 seconds, so that the average power density on the surface of the antenna aperture is 0.2W / cm 2 .

[0057] At the 1200th second in the process, the test script executes a preset fast- varying energy perturbation injection. At this time, on top of the existing slow- varying baseline thermal load, the multi-scale power injection array additionally applies a square wave energy pulse with a duration of 100 ms and a peak power density of 0.3 W / cm 2 to a specific region (corresponding to 64 T / R components in the upper right corner of the antenna).

[0058] To completely capture this thermal shock event, the collaborative control and data processing center instructs the sparse holographic measurement array to continuously collect data at a maximum time resolution of 10 microseconds within a time window before and after the time point.

[0059] After the test ends, the collaborative control and data processing center processes and correlationally analyzes all the collected time series data. The analysis results of the data in the 0-1800 second long period show that the key performance indicators of the antenna under test present a slow and continuous degradation consistent with the time scale of the slow- varying baseline thermal load: the cumulative peak gain decreases by 0.8 dB, the cumulative beam pointing error drifts by 0.05 degrees, and the first sidelobe level increases by 1.5 dB. The system diagnoses accordingly that the performance degradation is dominated by thermal mechanical effects caused by thermal deformation of the overall antenna structure under the cumulative thermal load.

[0060] The analysis of the high time resolution data before and after the 1200th second reveals a different physical mechanism. After the fast- varying energy perturbation injection, the peak gain additionally presents a sharp depression with a duration of about 1.5 seconds on the original slow- decreasing trend, with a maximum instantaneous decrease of 0.5 dB, and the beam pointing produces a rapid shift of 0.08 degrees within 200 ms, which is then gradually recovered. Since the characteristic time of the response is directly related to the millisecond- level energy pulse, the system diagnoses that this transient performance degradation is caused by the device- level thermoelectric effect of the T / R components in the perturbed region due to the sharp rise of the internal semiconductor junction temperature.

[0061] The complete execution of the application example not only reproduces the steady- state thermal performance degradation of the antenna under test in on- orbit operation, but also successfully captures and distinguishes the performance influences dominated by the thermal mechanical effect and the thermoelectric effect of two different physical mechanisms, providing direct and quantitative data support for the design optimization and thermal control strategy verification of the antenna.

[0062] Although embodiments of the present application have been shown and described, it is to be understood that various modifications, substitutions, replacements and changes can be made to these embodiments without departing from the principles and spirit of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A Ka phased array antenna thermal vacuum test system, characterized by, The application relates to a test system for testing a phased array antenna, comprising: a vacuum chamber; a test fixture for carrying the phased array antenna to be tested; a multi-scale power injection array installed in the vacuum chamber for non-contact injection of controllable microwave energy to the phased array antenna to be tested to simulate dynamic thermal load inside the phased array antenna to be tested; a sparse holographic measurement array installed in the vacuum chamber and statically arranged in a radiation near-field area of the phased array antenna to be tested for instantaneous acquisition of sparse samples of electromagnetic wave field emitted by the phased array antenna to be tested; and a cooperative control and data processing center connected with the multi-scale power injection array and the sparse holographic measurement array respectively for cooperative control of injection timing of the microwave energy and acquisition timing of the sparse samples of electromagnetic wave field and reconstruction of a far-field pattern of the phased array antenna to be tested according to the sparse sample data of electromagnetic wave field. The microwave energy injected by the multi-scale power injection array has a frequency set to be absorbed by a T / R component inside the phased array antenna to be tested and converted into heat energy. The dynamic thermal load generated by the multi-scale power injection array comprises: a slowly-varying reference thermal load with slowly-varying power density in space and time for simulating a reference thermal distribution of the phased array antenna under a specific mission profile; and a fast-varying energy perturbation which is an energy pulse superimposed on the slowly-varying reference thermal load and is local in time and space. The sparse holographic measurement array is composed of multiple fixed wide-beam probes without any mechanical moving parts, and the probes are arranged in a non-uniform sparse manner. The cooperative control and data processing center is configured to reconstruct the complete electric field distribution of the aperture plane of the phased array antenna to be tested from the sparse sample data of electromagnetic wave field by solving underdetermined equations based on the compressed sensing theory, and further calculate the far-field pattern through near-field to far-field transformation. The cooperative control and data processing center is configured to instruct the sparse holographic measurement array to perform continuous acquisition with high time resolution within a time window of injection of the fast-varying energy perturbation by the multi-scale power injection array to capture the transient radio frequency response of the phased array antenna to be tested caused by the fast-varying energy perturbation.

2. The Ka phased array antenna hot vacuum test system of claim 1, wherein: The cooperative control and data processing center is further configured to extract key performance indicators in the reconstructed far-field pattern and perform correlation analysis on the time evolution of the key performance indicators and the injected dynamic thermal load to diagnose the physical mechanism causing the performance change of the phased array antenna to be tested.

3. The Ka phased array antenna thermal vacuum test system of claim 1, wherein: The correlation analysis comprises: analyzing thermal mechanical effects based on the response of the key performance indicators to the slowly-varying reference thermal load; and analyzing device-level thermoelectric effects based on the response of the key performance indicators to the fast-varying energy perturbation. The multi-scale power injection array is a phased array antenna, and the cooperative control and data processing center controls the excitation amplitude and phase of each array element to form a preset spatio-temporal power density distribution on the surface of the phased array antenna to be tested. The application further relates to a test method for testing a phased array antenna, comprising the following steps: placing the phased array antenna to be tested in a vacuum low-temperature environment; non-contact injection of microwave energy to the phased array antenna to be tested by the multi-scale power injection array to generate dynamic thermal load inside the phased array antenna to be tested, wherein the dynamic thermal load comprises a slowly-varying reference thermal load and a fast-varying energy perturbation superimposed on the slowly-varying reference thermal load; and acquiring sparse samples of electromagnetic wave field emitted by the phased array antenna to be tested by the sparse holographic measurement array.

4. The Ka phased array antenna thermal vacuum test system of claim 1, wherein: ​ 5. The Ka phased array antenna thermal vacuum test system of claim 1, wherein: ​ 6. The Ka phased array antenna thermal vacuum test system of claim 3, wherein: ​ 7. The Ka phased array antenna thermal vacuum test system of claim 1, wherein: ​ 8. The Ka phased array antenna hot vacuum test system of claim 7, wherein: ​ ​ ​ 9. The Ka phased array antenna thermal vacuum test system of claim 1, wherein: ​ 10. A method for thermal vacuum test of Ka phased array antenna, the thermal vacuum test system of Ka phased array antenna according to any one of claims 1-9, characterized in that: ​ ​ ​ During the injection of microwave energy, a sparse sample of electromagnetic wave field emitted by the phased array antenna under test is collected by a fixed sparse holographic measurement array; Based on the collected sparse sample of electromagnetic wave field, a sequence of transient far-field patterns of the phased array antenna under test is reconstructed by a computational imaging algorithm; The change of performance indicators in the sequence of far-field patterns is correlated with the generated dynamic thermal load to diagnose the thermal and electrical coupling characteristics of the phased array antenna under test.

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