设计了一种测量电子器件电磁场分布的近场扫描系统，用于电磁兼容测试。首先，设计了一种四层印刷电路板结构的磁场探头，其工作频率达12 GHz，空间分辨率为2 mm，仿真与实测结果吻合较好，并对探头进行了校准。其次，实现了近场扫描的自动化，采用LabVIEW设计上位机软件，STM32作为运动控制核心，通过串口接收上位机数据，并控制步进电机带动探头移动，实现定点扫描，上位机通过局域网与矢量网络分析仪实现通信，完成数据的读取与保存。最后，通过上位机对数据进行可视化处理，在扫描完成时对结果进行校准，并实时生成被测物体的场强分布图，实现电磁场分布数据可视化。场强测试结果与电磁仿真结果吻合较好，可用于分析电磁耦合路径及实现近场与远场的转换。
This paper develops a design of near-field scanning system for measuring the electromagnetic (EM) field radiated by electronic devices for EM compatibility. Firstly, a magnetic field probe implemented on four-layer printed circuit board (PCB) structure is designed, with a working frequency of up to 12 GHz and a spatial resolution of 2 mm. The simulation results match well with the experimental measurements, and the probe is calibrated accordingly. Secondly, automation of the near-field scanning is achieved by designing a position machine using LabVIEW, with the STM32 serving as the motion control core. The STM32 receives the positioning data through the serial port, and controls the stepper motor to drive the probe for fixed-point scanning. The position machine communicates with the vector network analyzer through the local area network to read and save data. Finally, the data is visualized by the position machine. The results are calibrated upon completion of the scanning process, producing a real-time visualization of the field distribution map of the tested object. The measured field strength results show good agreement with electromagnetic simulation results, demonstrating the system’s suitability for analyzing electromagnetic coupling paths and transitioning between near-field and farfield regions.
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