屏蔽效能测试用双焦点平面腔的设计与应用

摘要

The dual focus flat cavity (DFFC) is a novel device for shielding effectiveness test. In order to determine the size of dual focus flat cavity (DFFC) in the frequency range 1~18GHz, the resonance characteristics of the elliptical resonator is researched through analytical and numerical methods. It is proved that the height of the cavity which mainly determines the resonant frequencies of TMmr1 and TEmr1 modes is the main factor that affects the transmission coefficient from input port to output port. So, the upper limit of frequency is defined as 80%of the cutoff frequency of TMmr1 mode. Furthermore the newly designed DFFC is manufactured. Finally the Shielding effectiveness test technology involving time domain gate is researched.%双焦点平面腔是一种新型的屏蔽效能测试装置。为确定1～18GHz双焦点平面腔的大小，用数值和解析的方法分析了椭圆谐振腔的谐振特性。证明了椭圆腔的高度是决定 TMmr1和TEmr1模的谐振频率的主要因素，也是影响输入输出端口传输系数的主要因素。因此，椭圆谐振腔的上限频率确定为TMmr1模的截止频率的80%。在椭圆谐振腔谐振特性分析的基础上制造了双焦点平面腔，并研究了时域门技术在双焦点平面腔法屏蔽效能测试中的应用。