Ultrawideband Real-Time Monitoring System Based on Electro-Optical Under-Sampling and Data Acquisition for Near-Field Measurement

Real-time electromagnetic field distribution of devices under test (DUT) can be used to diagnose and analyze the system electromagnetic compatibility (EMC). An ultrawideband real-time monitoring system based on electro-optical under-sampling and data acquisition is proposed in this article and then can be used in small and complex measurement space like intelligent car, high-speed train, plane, and weapon. The monitoring system consists of a near-field magnetic probe (9 kHz-20 GHz), a near-field electric probe (9 kHz-43.5 GHz), an electro-optical under-sampling module, and a data acquisition module. First, the ultrawideband signal (≤50 GHz) is measured by the near-field probes. Then, the ultrawideband signal is moved into a narrow band (a few tens of MHz) by the electro-optical module. Finally, the narrow band signal is captured and analyzed by the data acquisition module. The field data measured under special working mode can be used to locate the weak noise source in many engineering applications.