Abstract: 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.

Key words: electromagnetic compatibility, near-field scanning, broadband magnetic field probe, automatic control, LabVIEW