In-system electromagnetic leakage detection method based on antenna internal calibration test

Abstract

The present invention relates to a method for detecting electromagnetic leakage in a system based on an internal calibration test of an antenna, comprising the following steps: S1, comparing and analyzing calibration test data before and after a mechanical experiment of a tested antenna array or module to determine whether there is a relatively obvious radio frequency leakage in the system; S2, analyzing the data to find the channel with the largest calibration amplitude or phase fluctuation, and observing the echo linear pulse pressure time domain waveform of the suspicious channel; S3, detecting and locating the suspicious radio frequency module. The detection method of the present application does not require the aid of specialized electromagnetic compatibility testers and equipment, does not require additional costs, and has almost no impact on the development cycle. By directly collecting and analyzing single-channel calibration test data, it is possible to quickly and efficiently assess whether there is radio frequency interference in the tested antenna array. If there is radio frequency interference in the system, the location of the radio frequency leakage source can be efficiently located.

Description

Technical Field

[0001] The present invention relates to the field of antenna microwave technology, and in particular to a method for detecting electromagnetic leakage in a system based on antenna internal calibration test. Background Art

[0002] Synthetic Aperture Radar (SAR) is an active microwave imaging sensor. It offers all-day, all-weather imaging capabilities. The images it captures reflect the microwave scattering characteristics of targets and possess a certain degree of penetration, making it a crucial technology for acquiring ground-based information. Spaceborne SAR, using satellites and other spacecraft as its mobile platform, possesses global observation capabilities and plays an irreplaceable role in global military reconnaissance, environmental remote sensing, natural disaster monitoring, and planetary exploration.

[0003] With the increasing demand for SAR satellite applications, not only has the satellite platform payload increased, but transmission technologies have also diversified, integrating data transmission, measurement and control, navigation, and other electronic instruments and components across different frequency bands. Furthermore, SAR operating bandwidth, pulse width, power density, operating modes, and functional requirements are becoming increasingly stringent. Within limited space, the level of integration is increasing, requiring complex electronic systems and wireless transceiver systems, including high-power transmit links, highly sensitive receive links, and high-speed digital processing circuits. As a key component of the payload or main payload of a remote sensing satellite, the SAR antenna's RF compatibility significantly impacts the overall satellite's functional performance, electromagnetic compatibility, and reliability. The most common RF compatibility issue with SAR antennas is electromagnetic interference or self-excitation caused by electromagnetic leakage within the SAR antenna system. Rapidly and efficiently detecting electromagnetic leakage within SAR antennas is of great practical significance to their engineering development.

[0004] Traditionally, antenna RF compatibility testing has been conducted using standard testing or on-site testing, performing electromagnetic compatibility tests on individual or grouped devices or systems in accordance with GJB151A, GJB152A, GJB1389A, or GB9254. This results in low test efficiency and difficulty in locating SAR antennas. Furthermore, RF compatibility testing is impractical and difficult to locate for highly integrated, multifunctional large-scale SAR phased array antennas. Furthermore, these traditional testing methods require specialized personnel and equipment, are costly and time-consuming, and may even be impossible in some situations.

[0005] Internal calibration is a crucial component of SAR antennas. Its primary function is to support the monitoring of the amplitude and phase characteristics of the radar antenna's main link. When the SAR antenna array is operating in the transmitting mode, the active single-unit coupling element transmits a signal to the internal calibration network. This network synthesizes all coupled signals and sends them to the backend for signal processing, thereby monitoring changes in the main link's transmit signal. When the SAR antenna array is operating in the receiving mode, the backend sends the RF signal to the internal calibration network, which distributes the signal to each radiating element or active channel and transmits it to the antenna's receiving link, thereby determining the amplitude and phase characteristics of the receiving link. SAR antenna internal calibration is characterized by high accuracy and stable performance. Furthermore, the signal strength of the calibration link is lower than that of the main link, making it more sensitive to electromagnetic leakage signals from the SAR antenna. During the development of SAR antennas, internal calibration testing is also a key component of SAR antenna performance testing. Summary of the Invention

[0006] In order to solve the existing technical problems, the present invention provides a method for detecting electromagnetic leakage in a system based on antenna internal calibration test.

[0007] The specific content of the present invention is as follows: A method for detecting electromagnetic leakage in a system based on antenna internal calibration test, comprising the following steps:

[0008] S1: Compare and analyze the calibration test data before and after the mechanical test of the antenna array or module under test to determine whether there is obvious RF leakage in the system;

[0009] S2, analyze the data to find the channel with the largest calibration amplitude or phase fluctuation, and observe the echo linear pulse compression time domain waveform of the suspicious channel;

[0010] S3: Detect and locate suspicious radio frequency modules.

[0011] Furthermore, in S1, the single-channel TR reception calibration amplitude and phase data of the antenna array or module under test are initially collected, recorded as data0, and then a mechanical experiment is carried out. After the test, the single-channel TR reception calibration amplitude and phase data are collected again, recorded as data1. After removing the system error of data1-data0, the amplitude and phase consistency of the antenna array or module under test are analyzed.

[0012] Furthermore, the amplitude and phase data of the two measurements are compared. If the amplitude and phase data are consistent, there is no suspicion of RF leakage in the antenna array or module under test.

[0013] If the amplitude and phase data are inconsistent, the compared data are further analyzed;

[0014] Find the channel with the largest calibration amplitude or phase fluctuation, and check the calibration amplitude or phase fluctuation of the corresponding channel and adjacent channels, as well as the corresponding radar echo linear pulse compression time domain waveform. If the waveform of the channel with the largest calibration amplitude or phase fluctuation shows nonlinear changes, and the calibration amplitude or phase fluctuation of its adjacent channels is correlated with it, it is preliminarily determined that there is RF leakage in the system.

[0015] Finally, the array is further analyzed for RF links to identify suspicious RF areas or modules near the channel with the largest calibration fluctuation.

[0016] Furthermore, after finding the suspicious radio frequency area or module near the channel with the largest calibration fluctuation, the sniffing method is used to detect and locate the suspicious radio frequency module near the channel with the largest calibration fluctuation.

[0017] Furthermore, the amplitude and phase stability of single-channel calibration at room temperature is: the cumulative amplitude / phase stability of the antenna array or module under test is better than ±0.1dB / ±1°; taking into account the stress release before and after mechanical vibration, and combined with engineering experience, usually, the consistency of amplitude and phase data means that the measured amplitude difference is less than ±0.15dB, and the phase difference is less than ±2°; the inconsistency of channel amplitude and phase data means that the measured amplitude difference is greater than ±0.15dB, and the phase difference is greater than ±2°; the suspected RF leakage here means that there is a relatively obvious RF leakage in the system, which usually causes the maximum channel fluctuation value: the measured amplitude difference of the receiving or transmitting single-channel calibration is greater than ±0.2dB, and the phase difference is greater than ±3°.

[0018] This detection method does not require specialized EMC testing personnel and equipment, incurs no additional costs, and has virtually no impact on the development cycle. By directly collecting and analyzing single-channel calibration test data, it quickly and efficiently assesses whether RF interference exists within the antenna system under test. If significant RF interference exists within the system, the source of the RF leakage can be efficiently located. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The specific embodiments of the present invention will be further explained below with reference to the accompanying drawings.

[0020] Figure 1 Schematic diagram of the flow of the method for detecting electromagnetic leakage in a system based on antenna internal calibration test of the present invention;

[0021] Figure 2 This is a schematic diagram of the calibration detection working principle;

[0022] Figure 3 This is a comparative analysis diagram of the actual calibration amplitude and phase of the EUT antenna with calibration fluctuation;

[0023] Figure 4 Schematic diagram of the receiving calibration amplitude fluctuation envelope of the suspicious EUT antenna module;

[0024] Figure 5 The pulse pressure time domain waveforms of the suspicious channel and adjacent channels;

[0025] Figure 6 This is a schematic diagram of detecting and locating a suspicious RF module near the channel with the largest calibration fluctuation;

[0026] Figure 7 Comparison of actual calibration amplitudes of the EUT antenna with good calibration consistency;

[0027] Figure 8 This is a phase comparison analysis diagram of the EUT antenna with good calibration consistency;

[0028] Figure 9 It is the pulse pressure time domain waveform of a channel with no suspected RF leakage or good electromagnetic compatibility performance. DETAILED DESCRIPTION

[0029] This embodiment discloses a method for detecting electromagnetic leakage within a system based on antenna internal calibration testing. The detection method includes four steps: performing a mechanical experiment on the antenna array or module under test (referred to as the EUT antenna), recording calibration test data before and after the mechanical experiment, and comparing and analyzing the calibration test data before and after the mechanical experiment; secondly, analyzing the data to find the channel with the largest calibration amplitude or phase fluctuation, and observing the echo linear pulse compression time domain waveform of the suspicious channel; finally, detecting and locating the suspicious radio frequency module.

[0030] Specifically, if Figure 1 As shown, the EUT antenna is first subjected to the initial single-channel TR reception calibration amplitude and phase data acquisition, recorded as data0, and then a mechanical experiment is carried out. After the test, the single-channel TR reception calibration amplitude and phase data acquisition is performed again, recorded as data1. After removing the systematic error, the amplitude and phase data of data1 and data0 are compared to analyze the EUT amplitude / phase consistency.

[0031] If the amplitude and phase data before and after are consistent and stable, it is preliminarily determined that the electromagnetic compatibility performance of the system is good. Otherwise, find the channel with the largest calibration amplitude or phase fluctuation based on the analysis data;

[0032] Check the linear pulse pressure time domain waveforms of the corresponding channel and adjacent channels to see whether the waveforms undergo nonlinear changes and whether there are regular oscillations. If no nonlinear changes occur, it is preliminarily determined that there is no RF leakage interference in the system. If nonlinear changes occur, perform RF link analysis on the array to identify suspicious RF areas or modules near the channel with the largest calibration fluctuations. Then, detect and locate the suspicious RF areas or modules.

[0033] This embodiment tests a SAR antenna array composed of N modules. First, the amplitude and phase stability of the single-channel calibration at room temperature is: the amplitude / phase accuracy and stability of the tested EUT antenna and the test system are cumulatively better than ±0.1dB / ±1°. This indicator serves as the benchmark for subsequent measured data interpretation.

[0034] First, collect the calibration test data before and after the EUT antenna mechanical experiment. Figure 2 In the system shown in FIG, N modules are connected to the calibration switch or power division network through the calibration network, and then connected to the internal calibrator. The internal calibrator transmits signals to the calibration switch or power division network and is excited by the excitation source. The calibration data is sent to the receiver, thereby obtaining the amplitude and phase data before and after.

[0035] Then compare the amplitude and phase data before and after. If the measured amplitude difference is less than ±0.15dB, the phase difference is less than ±2°, and the amplitude and phase comparison data distribution is random, then the EUT antenna currently does not have any suspicion of RF leakage in the system. Figure 7 and Figure 8 shown.

[0036] If the amplitude and phase data are inconsistent, that is, the measured amplitude difference is greater than ±0.15dB and the phase difference is greater than ±2°, such as Figure 3 As shown, we further analyze the compared data to find the channel with the largest calibration amplitude or phase fluctuation, and its adjacent channels have related oscillations, such as Figure 4 As shown, it can be determined that channel 1 of the module is the most suspicious.

[0037] Check the radar echo linear pulse compression time domain waveform of the suspected channel 1 and adjacent channels of the EUT antenna. If the waveform of the channel with the largest calibration amplitude or phase fluctuation has nonlinear changes, there may be RF leakage in the system, such as Figure 5 As shown; there is no electromagnetic interference or acceptable channel radar echo linear pulse compression time domain waveform as shown Figure 9 shown.

[0038] Finally, further RF link analysis is performed on the array to find out the suspicious RF area or module near the channel with the largest calibration fluctuation; the sniffing method is used to detect and locate the suspicious RF module near the channel with the largest calibration fluctuation, and the suspicious module is removed for electromagnetic leakage detection, such as Figure 6 As shown in the figure, for channels initially identified as having RF leakage, preliminary analysis combined with the RF link signal level can identify the suspected device or location of RF leakage. If necessary, sniffing detection and location can be performed using a small antenna probe and spectrum analyzer in the same frequency band. This ultimately completes the RF leakage detection and location of the EUT antenna.

[0039] The detection method of the present application can be carried out at multiple stages of SAR antenna integration, debugging and testing. There is no need to leave electromagnetic compatibility testing until the radar overall or whole satellite system stage, which can avoid the various cost losses such as manpower and material resources and cycle delays caused by electromagnetic compatibility issues after the SAR antenna leaves the factory. The method is highly economical and low-cost. It can quickly locate the electromagnetic interference source directly through the analysis of single-channel calibration data. It does not require the help of specialized electromagnetic compatibility testers and equipment, does not require additional costs, and has almost no impact on the development cycle. At the same time, the method has the characteristics of strong real-time performance. Inserting this data analysis or detection and positioning work during the development of the antenna system has almost no impact on the development cycle. The internal calibration system is stable and has high test accuracy, with amplitude accuracy better than ±0.1dB and phase accuracy better than ±1°; the method is highly applicable and is suitable for phased array antennas with high-precision and stable calibration functions, including satellite-borne platforms.

[0040] In the above description, many specific details are set forth in order to fully understand the present invention. However, the above description is only a preferred embodiment of the present invention. The present invention can be implemented in many other ways different from those described herein, so the present invention is not limited to the specific implementation disclosed above. At the same time, any person skilled in the art can make many possible changes and modifications to the technical solution of the present invention using the methods and technical contents disclosed above without departing from the scope of the technical solution of the present invention, or modify it into an equivalent embodiment of equivalent changes. Any simple modification, equivalent change and modification made to the above embodiment based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the scope of protection of the technical solution of the present invention.

Claims

1. A method for detecting electromagnetic leakage in a system based on antenna internal calibration test, characterized by: The steps include: S1: Compare and analyze the calibration test data before and after the mechanical test of the antenna array or module under test to determine whether there is any RF leakage in the system; S2, analyze the data to find the channel with the largest calibration amplitude or phase fluctuation, and observe the echo linear pulse compression time domain waveform of the suspicious channel; S3, detect and locate the suspicious radio frequency module; Compare the amplitude and phase data of the two times. If the amplitude and phase data are consistent, there is no suspicion of RF leakage in the antenna system under test or the electromagnetic compatibility performance of the antenna system under test is good. If the amplitude and phase data are inconsistent, the compared data are further analyzed; Find the channel with the largest calibration amplitude or phase fluctuation, and check the calibration amplitude or phase fluctuation of the corresponding channel and adjacent channels, as well as the corresponding radar echo linear pulse compression time domain waveform. If the waveform of the channel with the largest calibration amplitude or phase fluctuation shows nonlinear changes, and the calibration amplitude or phase fluctuation of its adjacent channels is correlated with it, it is preliminarily determined that there is RF leakage in the system. Finally, the array is further analyzed for RF links to identify suspicious RF areas or modules near the channel with the largest calibration fluctuation.

2. The method for detecting electromagnetic leakage in a system based on antenna internal calibration test according to claim 1, characterized in that: In S1, the single-channel TR reception calibration amplitude and phase data of the antenna array or module under test are initially collected, recorded as data0, and then a mechanical experiment is carried out. After the test, the single-channel TR reception calibration amplitude and phase data are collected again, recorded as data1. After removing the systematic error of data1-data0, the amplitude and phase consistency of the antenna array or module under test are analyzed.

3. The method for detecting electromagnetic leakage in a system based on antenna internal calibration test according to claim 1, wherein: After finding the suspicious RF area or module near the channel with the largest calibration fluctuation, the sniffing method is used to detect and locate the suspicious RF module near the channel with the largest calibration fluctuation.

4. The method for detecting electromagnetic leakage in a system based on antenna internal calibration test according to claim 1, wherein: The room temperature stability of the amplitude and phase of single-channel calibration is: the cumulative amplitude / phase stability of the antenna array or module under test is better than ±0.1dB / ±1°. Taking into account the stress release before and after mechanical vibration and combined with engineering experience, generally, consistent amplitude and phase data means the measured amplitude difference is less than ±0.15dB, and the phase difference is less than ±2°. Inconsistent channel amplitude and phase data means the measured amplitude difference is greater than ±0.15dB, and the phase difference is greater than ±2°. Suspected RF leakage here refers to the presence of significant RF leakage within the system, which usually causes the maximum channel fluctuation: the measured amplitude difference of the receive or transmit single-channel calibration is greater than ±0.2dB, and the phase difference is greater than ±3°.

Images