A Ka phased array antenna hot vacuum test system

Abstract

The application relates to the field of antenna testing and discloses 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 and used for non-contact injection of controllable microwave energy to the phased array antenna to be tested so as to simulate dynamic thermal load inside the phased array antenna to be tested, a sparse holographic measurement array installed in the vacuum cabin body and statically arranged in a radiation near-field area of the phased array antenna to be tested and used for instantaneous collection of sparse samples of an 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. The multi-scale power injection array can not only simulate a slowly-changing reference thermal load under a task profile, but also superimpose rapid energy disturbance in a specific area, so that high-fidelity simulation of a complex thermal environment of an antenna in orbit is realized.

Description

Technical Field

[0001] This invention relates to the field of antenna testing, specifically to a thermal vacuum testing system for a Ka phased array antenna. Background Technology

[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 these antennas, such as antenna gain, beam pointing accuracy, and sidelobe level, is highly sensitive to operating temperature and internal temperature gradients. During on-orbit operation, the antennas undergo extreme temperature cycling caused by alternating direct solar radiation and deep-space background radiation. Simultaneously, the power consumption variations of the internal active transceiver (T / R) components under different operating modes also generate a dynamic and non-uniform temperature distribution across the antenna aperture. Therefore, conducting thermal vacuum tests on the ground to comprehensively and accurately verify their on-orbit performance and operational reliability is an essential technical step before satellite launch.

[0003] In the thermal vacuum testing of phased array antennas, a core technical challenge lies in how to realistically reproduce the complex dynamic thermal loads they experience during on-orbit operation. Currently, the main techniques used to simulate external heat flow include contact heaters and non-contact infrared lamp arrays.

[0004] The method using contact heating elements (e.g., resistive thin-film heaters) requires directly attaching the heating element to the surface of the antenna under test. This method has several inherent drawbacks. First, attaching the heating element alters the original thermal properties of the antenna surface, introducing additional heat capacity and heat transfer paths, thus interfering with the accuracy of the test results. Second, the physical size and wiring of the heating element limit its spatial resolution, making it difficult to generate a fine, non-uniform thermal map consistent with the actual power consumption distribution. Third, the slow response speed of resistive heating elements and their thermal inertia make them unable to simulate rapidly changing thermal shocks, failing to meet the requirements for evaluating transient effects.

[0005] While non-contact infrared lamp arrays avoid the contamination problems associated with contact methods to some extent, their simulation fidelity remains significantly limited. Conventional infrared lamp arrays are primarily used to provide large-area, uniform, or slowly varying background thermal environments. Their optical systems and control methods struggle to precisely "carve" energy into specific areas, making it impossible to create complex, high-gradient, non-uniform thermal load distributions. More critically, infrared filaments have extremely high thermal inertia, with on / off response times typically on the order of seconds, completely failing to meet the requirement of injecting a rapid energy pulse with a duration on the order of milliseconds or even microseconds at a specific location.

[0006] Therefore, existing thermal vacuum testing methods cannot simultaneously simulate, in a non-contact, high-fidelity manner, the slowly varying reference thermal loads experienced by a phased array antenna, determined by the mission profile, and the rapidly varying local energy disturbances caused by specific operating mode switching or sudden changes in the external environment. This makes it impossible to effectively test and differentiate the physical mechanisms of the cumulative thermal deformation effect of the antenna structure and the transient junction temperature effect of active devices, which have different time scales, in a single experiment. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides a Ka phased array antenna thermal vacuum test system. This system solves the problem that existing technologies cannot simultaneously reproduce the slowly varying non-uniform reference thermal load and the rapidly varying local energy disturbance experienced by the phased array antenna in a non-contact and high-fidelity manner in a single test. Consequently, they cannot effectively distinguish and diagnose the performance degradation mechanism caused by thermal effects at different time scales.

[0008] To achieve the above objectives, the present invention provides the following technical solution: a Ka-phased array antenna thermal vacuum test system, comprising:

[0009] Vacuum chamber;

[0010] Test fixtures are used to support the phased array antenna under test;

[0011] A multi-scale power injection array, installed inside the vacuum chamber, is used to inject controllable microwave energy into the phased array antenna under test in a non-contact manner to simulate the dynamic thermal load inside the phased array antenna under test.

[0012] A sparse holographic measurement array is installed inside the vacuum chamber and statically arranged in the radiation near-field region of the phased array antenna under test, for instantaneously acquiring sparse samples of the electromagnetic wave field emitted by the phased array antenna under test.

[0013] The collaborative control and data processing center is connected to the multi-scale power injection array and the sparse holographic measurement array, respectively, to collaboratively control the injection timing of the microwave energy and the acquisition timing of the sparse electromagnetic field samples, and to reconstruct the far-field radiation pattern of the phased array antenna under test based on the sparse electromagnetic field sample data.

[0014] According to the above technical solution, by setting up a multi-scale power injection array, a non-uniform thermal load distribution highly consistent with the actual operating state can be formed on the surface of the phased array antenna under test in a non-contact manner. This array radiates controllable microwave energy to the antenna under test and, through its independent high-speed electronic control capability for each radiating element, achieves multi-scale simulation of the thermal load in both spatial and temporal dimensions. This solves the problem that existing technologies cannot simultaneously assess and effectively distinguish performance degradation caused by different physical mechanisms in a single test, greatly improving the accuracy and comprehensiveness of ground-based thermal vacuum testing of phased array antennas.

[0015] Preferably, the microwave energy injected by the multi-scale power injection array is frequency-set so that it can be absorbed by the T / R components inside the phased array antenna under test and converted into heat energy.

[0016] Preferably, the dynamic thermal load generated by the multi-scale power injection array includes:

[0017] Slowly varying reference thermal load, whose power density varies slowly in space and time, is used to simulate the reference thermal distribution of the phased array antenna under test in a specific mission profile.

[0018] Rapidly varying energy disturbances are energy pulses that are superimposed on a slowly varying reference thermal load and are localized in both time and space.

[0019] Preferably, the sparse holographic measurement array consists of multiple fixed wide-beam probes without any mechanical moving parts, and the probes are arranged in a non-uniform sparse manner.

[0020] Preferably, the collaborative control and data processing center is configured to reconstruct the complete electric field distribution of the aperture plane of the phased array antenna under test from sparse sample data of electromagnetic wave field by solving underdetermined equations based on compressed sensing theory, and then calculate the far-field radiation pattern by near-field to far-field transformation.

[0021] 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 within the time window of injecting rapidly changing energy disturbances into the multi-scale power injection array, so as to capture the transient radio frequency response of the phased array antenna under test caused by the rapidly changing energy disturbances.

[0022] Preferably, the collaborative control and data processing center is further configured to: extract key performance indicators from the reconstructed far-field radiation 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 that causes the performance change of the phased array antenna under test.

[0023] Preferably, the association analysis includes:

[0024] Thermomechanical effects are analyzed based on the response of key performance indicators to slowly varying reference thermal loads.

[0025] Based on the response of key performance indicators to rapidly changing energy disturbances, the device-level thermoelectric effect is analyzed.

[0026] 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 array element to form a preset spatiotemporal power density distribution on the surface of the phased array antenna under test.

[0027] A thermal vacuum test method for a Ka-phased array antenna includes the following steps:

[0028] The phased array antenna under test was placed in a vacuum cryogenic environment.

[0029] Microwave energy is injected into the phased array antenna under test in a non-contact manner through a multi-scale power injection array to generate a dynamic thermal load inside it. The dynamic thermal load includes a slowly varying reference thermal load and a fast varying energy disturbance superimposed on the slowly varying reference thermal load.

[0030] While injecting microwave energy, a fixed sparse holographic measurement array is used to instantaneously acquire sparse samples of the electromagnetic wave field emitted by the phased array antenna under test.

[0031] Based on the collected sparse electromagnetic wave field samples, the transient far-field radiation pattern sequence of the phased array antenna under test is reconstructed by computational imaging algorithm;

[0032] Correlation analysis is performed on the performance index changes and dynamic thermal loads generated in the far-field radiation pattern sequence to diagnose the thermal and electrical coupling characteristics of the phased array antenna under test.

[0033] This invention provides a thermal vacuum testing system for Ka-phased array antennas. It has the following advantages:

[0034] 1. By setting up a multi-scale power injection array, the present invention can form a non-uniform thermal load distribution on the surface of the phased array antenna under test in a non-contact manner that is highly consistent with the actual working state. This array can not only simulate the slowly varying reference thermal load under the mission profile, but also superimpose rapid energy disturbances in specific areas, thereby realizing high-fidelity simulation of the complex thermal environment of the antenna in orbit.

[0035] 2. This invention replaces the traditional mechanical scanning near-field measurement by using a static sparse holographic measurement array and combining it with a computational imaging algorithm based on compressed sensing. This scheme can complete a holographic snapshot of the entire radiation field in microseconds without any mechanical movement, thus realizing high temporal resolution continuous monitoring of antenna RF performance.

[0036] 3. This invention establishes a collaborative control and data processing center to uniformly control the multi-scale power injection array and the sparse holographic measurement array, integrating the separate thermal excitation and RF measurement stages of traditional testing into a software-defined automated test process. This allows the entire complex testing process to be executed automatically by a preset script, completely eliminating the reliance on manual equipment switching and the need for multi-operator collaboration, thereby significantly reducing labor costs and the risk of operational errors, while ensuring the continuity and high efficiency of the testing process. Attached Figure Description

[0037] Figure 1 This is a system module architecture diagram of the present invention;

[0038] Figure 2 This is a schematic diagram illustrating the step logic of the present invention;

[0039] Figure 3 This is a schematic diagram of the steps of the present invention;

[0040] Figure 4 This is a schematic diagram of the physical structure of the cabin of the present invention;

[0041] Figure 5 This is a schematic diagram of the physical structure of the collaborative control and data processing center of the present invention. Detailed Implementation

[0042] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0043] Please see the appendix Figure 1 -Appendix Figure 5 This invention provides a Ka-phased array antenna thermal vacuum test system, comprising:

[0044] Vacuum chamber;

[0045] Test fixtures are used to support the phased array antenna under test;

[0046] A multi-scale power injection array, installed within a vacuum chamber, is used to inject controllable microwave energy into the phased array antenna under test (TAD) in a non-contact manner to simulate the dynamic thermal load inside the TAD antenna. The frequency of the microwave energy injected by the multi-scale power injection array is set so that it can be absorbed and converted into heat energy by the T / R components inside the TAD antenna. The dynamic thermal load generated by the multi-scale power injection array includes:

[0047] Slowly varying reference thermal load, whose power density varies slowly in space and time, is used to simulate the reference thermal distribution of the phased array antenna under test in a specific mission profile.

[0048] Rapidly varying energy disturbances are energy pulses superimposed on a slowly varying reference thermal load and are localized in both time and space. The multi-scale power injection array is a phased array antenna. The coordinated control and data processing center controls the excitation amplitude and phase of each array element to form a preset spatiotemporal power density distribution on the surface of the phased array antenna under test.

[0049] The sparse holographic measurement array is installed inside a vacuum chamber and statically arranged in the near-field radiation region of the phased array antenna under test. It is used to instantaneously acquire sparse samples of the electromagnetic wave field emitted by the phased array antenna under test. The sparse holographic measurement array consists of multiple fixed wide-beam probes without any mechanical moving parts, and the probes are arranged in a non-uniform sparse manner.

[0050] The Cooperative Control and Data Processing Center, connected to both the multi-scale power injection array and the sparse holographic measurement array, is used to coordinate the timing of microwave energy injection and the timing of sparse electromagnetic field sample acquisition. It then reconstructs the far-field radiation pattern of the phased array antenna under test based on the sparse electromagnetic field 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 under test from the sparse electromagnetic field sample data by solving underdetermined equations based on compressed sensing theory, and then calculates the far-field radiation pattern through near-field to far-field transformation.

[0051] The collaborative control and data processing center is configured to: within the time window of the multi-scale power injection array injecting rapidly varying energy perturbations, instruct the sparse holographic measurement array to perform continuous high-temporal-resolution acquisition to capture the transient RF response of the phased array antenna under test caused by the rapidly varying energy perturbations. The collaborative control and data processing center is also configured to: extract key performance indicators from the reconstructed far-field pattern and perform correlation analysis between the temporal evolution of these key performance indicators and the injected dynamic thermal loads to diagnose the physical mechanisms causing performance changes in the phased array antenna under test. The correlation analysis includes:

[0052] Thermomechanical effects are analyzed based on the response of key performance indicators to slowly varying reference thermal loads.

[0053] Based on the response of key performance indicators to rapidly changing energy disturbances, the device-level thermoelectric effect is analyzed.

[0054] Specifically, the present invention includes a vacuum chamber, a multi-scale power injection array, a sparse holographic measurement array, a collaborative control and data processing center, and a test fixture for carrying the phased array antenna under test.

[0055] The vacuum chamber, multi-scale power injection array, sparse holographic measurement array, and test fixtures are all connected to the vacuum chamber. The multi-scale power injection array and sparse holographic measurement array are respectively arranged on both sides of the phased array antenna under test, and both are connected to the collaborative control and data processing center for signal and data communication. The vacuum chamber consists of a vacuum pump assembly and a liquid nitrogen cooling plate. The vacuum pump assembly is used to evacuate the interior of the vacuum chamber to a specified vacuum level, preferably below 10⁻⁶. -3 Pascal; liquid nitrogen cold plates cover the inner wall of the vacuum chamber to provide a stable deep space cryogenic background environment, preferably a background temperature of about 77K.

[0056] The multi-scale power injection array is a two-dimensional planar phased array antenna, whose array surface consists of a large number of microwave radiating elements, preferably microstrip patch antenna elements. The operating frequency of this array is set to a frequency band that can be effectively absorbed by the semiconductor materials and lossy dielectrics in the T / R components inside the phased array antenna under test and mainly converted into heat energy, rather than the operating 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 radiating element of the array, thereby forming a specific spatiotemporal power density distribution on the aperture plane of the phased array antenna under test.

[0057] The sparse holographic weighing array is a two-dimensional planar array composed of multiple statically fixed wide-beam probes, 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 positioned in the near-field radiation region of the phased array antenna under test to synchronously acquire sparse samples of the electromagnetic wave field radiated by the phased array antenna under test in space at any given time, and transmits the acquired complex voltage signals to the collaborative control and data processing center.

[0058] The collaborative control and data processing center comprises a main control computer, a real-time controller, a high-performance computing unit, and a data acquisition and storage system. The real-time controller, preferably a field-programmable gate array (FPGA), generates high-precision clock synchronization signals and control commands, which are then distributed to the multi-scale power injection array and the sparse holographic measurement array, respectively. The high-performance computing unit, preferably a graphics processing unit (GPU) server, executes subsequent electromagnetic field reconstruction algorithms. The data acquisition and storage system receives and stores large volumes of measurement data transmitted from the sparse holographic measurement array.

[0059] In one specific embodiment, the complete process of this testing method is as follows:

[0060] First, experimental preparation and system calibration are performed. The phased array antenna under test is mounted on the test fixture and placed in a predetermined position within the vacuum chamber. The vacuum chamber is activated, evacuated to the specified vacuum level, and the liquid nitrogen cooling plate is turned on. After the background temperature stabilizes, system calibration is performed. The calibration process includes calibrating the position and response characteristics of each probe 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 through electromagnetic simulation or actual measurement methods.

[0061] Secondly, dynamic thermal load generation and injection are performed. Based on a preset mission profile simulating the on-orbit operation of the antenna, the Cooperative Control and Data Processing Center first calculates the slow-varying reference thermal load distribution that should exist on the aperture plane of the phased array antenna under test under this profile. Then, by controlling the excitation amplitude and phase of each element in the multi-scale power injection array, this slow-varying reference thermal load is formed on the surface of the phased array antenna under test. During the stable application of this slow-varying reference thermal load, the Cooperative Control and Data Processing Center, according to a preset test script, controls the multi-scale power injection array to inject one or more fast-varying energy disturbances at specific times and locations.

[0062] Furthermore, high temporal resolution electromagnetic field synchronous acquisition is performed. During the entire dynamic thermal load injection period, especially before and after the time window of injecting rapidly changing energy disturbance, the sparse holographic measurement array is instructed by the collaborative control and data processing center to perform high temporal resolution electromagnetic wave field sparse sample acquisition. The time interval of acquisition, i.e. the time difference between two holographic snapshots, is set to a characteristic time scale that can capture the transient radio frequency response caused by the rapidly changing energy disturbance, preferably on the order of microseconds or milliseconds.

[0063] Then, the transient electromagnetic field is reconstructed and calculated. The collaborative control and data processing center receives and processes a large amount of time-series data acquired by the sparse holographic measurement array. For the sparse sample data of the electromagnetic wave field at each acquisition moment, a computational imaging algorithm based on compressed sensing is used to reconstruct the complete electric field distribution of the aperture plane of the phased array antenna under test at that moment. Then, the far-field radiation pattern at that moment is calculated through a near-field to far-field transformation algorithm, thereby generating a dynamic far-field radiation pattern sequence that can fully characterize the evolution of antenna performance over time.

[0064] Finally, multi-scale temporal correlation diagnosis is performed, extracting curves showing the changes of key performance indicators over time from the generated dynamic far-field pattern sequence. By aligning and comparing these curves with the injected dynamic thermal load in time, the correlation between the two is analyzed, thereby distinguishing and diagnosing different physical mechanisms leading to antenna performance degradation.

[0065] During the generation of dynamic thermal load, the slowly varying reference thermal load P buseThe generation of (r′,t) is 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 beam pointing function, and then it is mapped to the aperture plane S. ap The power density distribution is continuous, while the rapidly changing energy perturbation P pert (r′,t) is designed as a pulse that is local in both space and time, and its mathematical form can be expressed as:

[0066] P pert (r′,t)=A p ·g(r′-r′0)·h(t-t0)

[0067] Among them, A p Let g(·) be the peak power density of the perturbation pulse, g(·) be the spatial distribution function, preferably a two-dimensional Gaussian function, used to focus energy on the region centered at r0′, and h(·) be the time envelope function, preferably a square wave pulse, used to apply a short-duration energy pulse at time t0.

[0068] 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 under test has sparse characteristics in a specific 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 through the sparse basis matrix Ψ to obtain the sparse coefficient vector α(t).

[0069] The reconstruction process involves solving the following equations to obtain the optimal estimate of the sparse coefficient vector.

[0070]

[0071] 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 results and the measurement data and the sparsity of the solution.

[0072] This optimization problem can be solved efficiently using algorithms such as the fast iterative threshold shrinkage algorithm. After that, you can pass A high-resolution aperture field was reconstructed.

[0073] In the process of multi-scale temporal correlation diagnosis, the first step is to start from the far-field pattern sequence E ff The time evolution curves of key performance indicators extracted from (θ,φ,t) can be preferably selected as peak gain K. guin (t), Beam pointing error K p.e. (t), Peak sidelobe level K psll (t) etc.

[0074] Subsequently, these key performance indicator curves were analyzed. Specifically, the macroscopic drift and variation trends of the key performance indicator curves over longer time scales (seconds to minutes) were analyzed in relation to the slowly varying reference thermal load P. base The variation curves are correlated to analyze the effects caused by cumulative thermomechanical effects such as material thermal expansion and structural deformation. Simultaneously, the analysis focuses on the effects of applying rapidly changing energy perturbations P. pert The transient response characteristics that appear on the key performance indicator curves around time t0 can be preferably peak deviation, response delay, recovery time, etc., to analyze the impact caused by rapid device-level thermoelectric effects such as transient changes in the semiconductor junction temperature inside the T / R component.

[0075] In this invention, the precise timing synchronization between the energy injection operation of the multi-scale power injection array and the field sample acquisition operation of the sparse holographic measurement array is ensured by a real-time controller, preferably a field-programmable gate array, within the collaborative control and data processing center. This real-time controller generates a highly stable master clock signal and distributes it to the control unit of the multi-scale power injection array and the data acquisition unit of the sparse holographic measurement array to establish a unified system time reference.

[0076] During the test execution phase, the main control computer loads a test sequence containing a series of instructions with precise timestamps into the real-time controller. This sequence specifies the execution of specific hardware operations at specific points in time.

[0077] Preferably, at time t start_p The command multi-scale power injection array begins injecting rapidly varying energy perturbations at time t. end_p End injection; simultaneously instruct the sparse holographic measurement array at times t before and after the perturbation injection window. start_m to t end_m Between them, at an extremely short time interval Δt m Continuous data collection is triggered.

[0078] Based on these timestamps, the real-time controller directly generates hardware trigger signals in the corresponding clock cycle, thereby achieving precise synchronization between the excitation action of the multi-scale power injection array and the measurement action of the sparse holographic measurement array on a microsecond-level time scale.

[0079] The system of this invention integrates the entire experimental process, including environment setup, system calibration, multi-scale thermal load injection, synchronous radio frequency field acquisition, data processing and analysis, into a software-defined automated test process. Before the test begins, the operator configures or loads a complete automated test script according to the test requirements. This script defines the parameters for the entire test process, which can preferably include the target vacuum level and temperature, the time-space distribution function of the slowly varying reference thermal load, the injection time, injection location, peak power and duration of one or more rapidly varying energy perturbations, and the acquisition rate and total duration of the sparse holographic measurement array.

[0080] After the experiment is started, the collaborative control and data processing center automatically parses the script and autonomously completes all operations. It controls the vacuum pump group and liquid nitrogen cooling plate to establish the experimental environment, executes the system calibration program, and precisely controls the multi-scale power injection array and sparse holographic measurement array to work together according to the timing defined in the script. Throughout the process, operators only need to monitor the system status without any manual intervention. This transformation of manual coordination and physical switching into automated execution of a pre-set script fundamentally eliminates the risk and uncertainty of test interruptions caused by untimely operation or personnel errors, ensuring the continuity and repeatability of the experimental process, and reducing the traditional requirement of two or more people to a single monitoring position.

[0081] The following will provide a more detailed explanation of the technical solution of this invention through a specific application example. This example aims to illustrate how this invention is applied to a specific Ka-phased array antenna and obtains quantifiable diagnostic results.

[0082] This example aims to test and diagnose the dynamic thermal and electrical coupling characteristics of a Ka-band spaceborne phased array antenna under a thermal vacuum environment.

[0083] This example aims to test and diagnose the dynamic thermal and electrical coupling characteristics of a Ka-band spaceborne phased array antenna under a thermal vacuum environment. The phased array antenna under test operates at a frequency of 30.0 GHz, has an array size of 256 elements in a 16x16 layout, and an aperture size of 15cmx15cm.

[0084] To conduct this experiment, the vacuum chamber was set to a vacuum level of 1.0 × 10⁻⁶. -5 Pa, and the background temperature of 77K is maintained by a liquid nitrogen cooling plate.

[0085] The operating frequency of the multi-scale power injection array is set to 24.0 GHz to ensure that energy is effectively absorbed by the T / R components of the antenna under test.

[0086] The sparse holographic measurement array is equipped with 300 wide-beam spiral antennas and its data acquisition rate is set to 100 kS / s, that is, a holographic snapshot is taken every 10 microseconds.

[0087] During the experiment, a pre-set automated test script was initiated. From 0 to 1800 seconds at the start of the experiment, a multi-scale power injection array injected a slowly varying reference thermal load onto the surface of the antenna under test. This load was designed to simulate the power distribution of the antenna performing a ground scanning task; its total power increased linearly with time, eventually reaching a steady state at 1800 seconds, resulting in an average power density of 0.2 W / cm² on the antenna aperture surface. 2 .

[0088] At the 1200-second mark of this process, the test script executes a pre-defined fast-changing energy perturbation injection. At this point, on top of the existing slow-changing reference thermal load, the multi-scale power injection array applies an additional energy perturbation to a specific region (corresponding to the 64 T / R components in the upper right corner of the antenna) for 100 ms, with a peak power density of 0.3 W / cm². 2 Square wave energy pulse.

[0089] To fully capture this thermal shock event, the Cooperative Control and Data Processing Center instructed the sparse holographic measurement array to continuously acquire data at the highest temporal resolution of 10 microseconds within the time window before and after this moment.

[0090] After the experiment, the collaborative control and data processing center processed and analyzed all the collected time-series data. Analysis of the long-term data from 0 to 1800 seconds showed that the key performance indicators of the antenna under test exhibited a slow and continuous degradation consistent with the time scale of the slowly varying reference thermal load: the peak gain decreased cumulatively by 0.8 dB, the beam pointing error drifted cumulatively by 0.05 degrees, and the first sidelobe level increased by 1.5 dB. Based on this, the system diagnosed that this performance degradation was dominated by thermomechanical effects, resulting from thermal deformation of the overall antenna structure under accumulated thermal load.

[0091] Analysis of high-temporal-resolution data around the 1200-second mark revealed different physical mechanisms. After the injection of rapidly changing energy perturbation, the peak gain exhibited an additional sharp dip lasting approximately 1.5 seconds, on top of its original slow decline trend, with a maximum instantaneous drop of 0.5 dB. Simultaneously, the beam pointing experienced a rapid shift of 0.08 degrees within 200 ms, before gradually recovering. Since the characteristic time of this response is directly related to the millisecond-level energy pulse, the system diagnosed this transient performance degradation as a device-level thermoelectric effect caused by a sharp increase in the semiconductor junction temperature inside the T / R component in the perturbed region.

[0092] The complete execution of this application example, through an automated test, not only reproduced the steady-state thermal performance degradation of the antenna under test during on-orbit operation, but also successfully captured and distinguished the performance effects dominated by two different physical mechanisms: thermomechanical effects and thermoelectric effects. This provides direct and quantitative data support for antenna design optimization and thermal control strategy verification.

[0093] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A thermal vacuum test system for a Ka-phased array antenna, characterized in that, include: Vacuum chamber; Test fixtures are used to support the phased array antenna under test; A multi-scale power injection array, installed inside the vacuum chamber, is used to inject controllable microwave energy into the phased array antenna under test in a non-contact manner to simulate the dynamic thermal load inside the phased array antenna under test. A sparse holographic measurement array is installed inside the vacuum chamber and statically arranged in the radiation near-field region of the phased array antenna under test, for instantaneously acquiring sparse samples of the electromagnetic wave field emitted by the phased array antenna under test. The collaborative control and data processing center is connected to the multi-scale power injection array and the sparse holographic measurement array, respectively, and is used to collaboratively control the injection timing of the microwave energy and the acquisition timing of the sparse electromagnetic field samples, and reconstruct the far-field radiation pattern of the phased array antenna under test based on the sparse electromagnetic field sample data. The dynamic thermal load generated by the multi-scale power injection array includes: Slowly varying reference thermal load, whose power density varies slowly in space and time, is used to simulate the reference thermal distribution of the phased array antenna under test in a specific mission profile. Rapidly varying energy disturbances are energy pulses that are superimposed on a slowly varying reference thermal load and are localized in both time and space. The sparse holographic measurement array consists of multiple fixed wide-beam probes without any mechanical moving parts, and the probes are arranged in a non-uniform sparse manner. The collaborative control and data processing center is configured to reconstruct the complete electric field distribution of the aperture plane of the phased array antenna under test from sparse sample data of electromagnetic wave field by solving underdetermined equations based on compressed sensing theory, and then calculate the far-field radiation pattern by near-field to far-field transformation. The multi-scale power injection array is a phased array antenna. The cooperative control and data processing center controls the excitation amplitude and phase of each array element to form a preset spatiotemporal power density distribution on the surface of the phased array antenna under test.

2. The Ka phased array antenna thermal vacuum test system according to claim 1, characterized in that: The microwave energy injected by the multi-scale power injection array is frequency-set so that it can be absorbed by the T / R components inside the phased array antenna under test and converted into heat energy.

3. The Ka phased array antenna thermal vacuum test system according to claim 1, characterized in that: The collaborative control and data processing center is configured to instruct the sparse holographic measurement array to perform continuous acquisition with high temporal resolution within the time window of injecting rapidly changing energy disturbances into the multi-scale power injection array, so as to capture the transient radio frequency response of the phased array antenna under test caused by the rapidly changing energy disturbances.

4. The Ka phased array antenna thermal vacuum test system according to claim 1, characterized in that: The collaborative control and data processing center is also configured to: extract key performance indicators from the reconstructed far-field radiation pattern, and perform correlation analysis on the time evolution of key performance indicators and the injected dynamic thermal load, so as to diagnose the physical mechanism that causes the performance change of the phased array antenna under test.

5. The Ka phased array antenna thermal vacuum test system according to claim 4, characterized in that: The association analysis includes: Thermomechanical effects are analyzed based on the response of key performance indicators to slowly varying reference thermal loads. Based on the response of key performance indicators to rapidly changing energy disturbances, the device-level thermoelectric effect is analyzed.

6. A method for thermal vacuum testing of a Ka phased array antenna, comprising a thermal vacuum testing system for a Ka phased array antenna according to any one of claims 1-5, characterized in that: Includes the following steps: The phased array antenna under test was placed in a vacuum cryogenic environment. Microwave energy is injected into the phased array antenna under test in a non-contact manner through a multi-scale power injection array to generate a dynamic thermal load inside it. The dynamic thermal load includes a slowly varying reference thermal load and a fast varying energy disturbance superimposed on the slowly varying reference thermal load. While injecting microwave energy, a fixed sparse holographic measurement array is used to instantaneously acquire sparse samples of the electromagnetic wave field emitted by the phased array antenna under test. Based on the collected sparse electromagnetic wave field samples, the transient far-field radiation pattern sequence of the phased array antenna under test is reconstructed by computational imaging algorithm; Correlation analysis is performed on the performance index changes and dynamic thermal loads generated in the far-field radiation pattern sequence to diagnose the thermal and electrical coupling characteristics of the phased array antenna under test.

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