Design Of Electromagnetic Near-field Scanning System

Nowadays,with the rapid development of electronic technology,the electronic products have become diversified,and the electromagnetic compatibility problems between equipment have become increasingly prominent and widely been concerned.It also promotes the development of EMC measurement technology rapidly.An electromagnetic near-field scanning system is designed in this paper,which can be used as a tool to test the electromagnetic problems of PCB boards.It can locate and measure quickly.It also provide effective measurement for the rectification of equipment and the EMC authentication.The main works of paper are as follows:1.An e-field probe is designed and made.Using the improved inverted F structure,the model is built and simulated by HFSS.Finally,probe is finished on the conical PCB board.The test results of vector network analyzer confirmed that the probe reached the design standards.2.A motion control scanning system is designed and made.The STM32 is the control core,and receive command from upper monitor through the USB interface.While controlling the stepper motor drives the ball screw to finish the linear displacement scanning motion.3.The upper computer software is designed.It uses interface designing function of VB and MATLAB GUI.The communication with spectrum analyzer is established through LAN to achieve set and control the spectrum analyzer.The data of spectrum analyzer are collected and stored.The collected data are visualize by upper computer software.The field strength distribution of test products are displayed with two-dimensional and stereoscopic.While completing the movement control of the scanning system,and automatic detection is realized.Through the experiment,the system can scan the electronic components or structures of the circuit board globally,and provide data for detecting the electromagnetic compatibility of products.During the test,the system runs stable and the e-field probe has good performance.The system can adjust the scanning resolution and replace the probes with different frequencies and performances.The field intensity distribution shows intuitionistic.