混响室条件下线缆共模干扰临界辐射干扰场强测试研究

Investigation on the Radiated Interference E-field Threshold Testing for Common-mode Interference of Transmission Lines in Reverberation Chambers

为在混响室中线缆共模干扰时的设备(EUT)进行临界辐射干扰场强测试,并确保与开阔场中测试结果一致,该文推导了线缆上共模电流满足的方程,将共模电流分解为相应的特征电流,计算了终端负载任意时线缆最大方向性系数的变化范围。以单导体传输线和同轴线为EUT,分别在混响室和开阔场中测试线缆的临界干扰场强,对计算结果进行了验证。结果表明:最大方向性系数的计算结果可以保证两种不同场地中测试结果的一致性,双线的共模干扰以及同轴线均可以等效为单线,且线缆弯曲对测试结果基本没有影响。

To test the radiated interference E-field threshold of Equipment Under Test(EUT)with commonmode interference of transmission lines in reverberation chambers and unify the test results with the open areas,the range of the maximum directivity of the lines with random loads is calculated by the derivation of the equation of the common-mode currents and decomposition of the currents into the corresponding characteristic ones.The calculated results are validated with the experiments performed in a reverberation chamber and an open area,respectively,with a single conductor line and a coaxial cable as the EUT.The theoretical and experimental results show that the test results in the two different areas can be unified with the calculated results.The common mode interference of two conductor lines and coaxial cables can be equivalent to single conductor lines and the bend of the lines almost has no influence on the test results.