电磁近场探测扫描系统的设计与实现

摘要

To test electromagnetic compatibility of electronic products, an electromagnetic near-field detecting and scanning system is designed and realized to scan PCB board and other electronic devices globally.The distribution of field strength displays intuitively. The system consists of three parts: spectrum analyzer, PC software and two-dimensional scanning platform. VB language is used to compose software to control spectrum analyzer, and MCU control two-dimensional scanning platform. Finally, complete electromagnetic near-field testing function is realized. A near-field probe applied to 6.35 GHz is designed,and the model is established by using Ansoft HFSS software.Then,the simulation results of return loss of -25.44 75 dB and voltage standing-wave ratio of 1.112 8 are obtained, and the object is manufactured.The actual probe is measured by using vector network analyzer,and the test results are in good agreement with the simulation results.After testing,the results show that the system is stable,the field distribution is visual and the field probe is accurate,which achieves the designing purpose.%为测试电子产品电磁兼容性,设计并实现了一种电磁近场探测的扫描系统,可以对PCB板等电子部件或结构进行全局扫描,并直观显示场强分布情况.该系统由频谱分析仪、上位机软件、二维扫描平台3部分组成,利用VB语言编写上位机软件控制频谱分析仪,使用单片机控制二维扫描平台,最终完成电磁近场测试功能.设计了应用于6.35 GHz的近场探头,使用Ansoft HFSS软件建立模型,然后得到回波损耗为-25.4475 dB,电压驻波比为1.1128的仿真结果,并制作实物.通过使用矢量网络分析仪对实物探头进行实测,测试结果与仿真结果基本一致.测试结果表明该系统运行稳定,场强分布显示直观,近场探头测试准确,达到了预期的设计目的.