混响室条件下环境场强测量位置选取准则

Investigation of selection criteria of environmental E-field intensity measurement position in reverberation chamber

针对在混响室条件下进行辐射敏感度测试时电磁环境场强难以度量的问题,分析了混响室内电场强度的统计特性,理论推导了有损混响室内场强空间相关系数表达式,并通过仿真分析验证了表达式的正确性。根据表达式得出有损混响室内相对距离大于半波长的两点间场强相互独立的结论,并由此推断出,混响室内环境场强测试位置与受试设备(EUT)距离应大于0.5倍波长,且应以此作为测量位置选取准则。采用仿真计算与实验验证相结合的方法分析了相对误差随测试点与EUT间相对距离的变化规律,对该准则进行了验证,结果表明,当测试点与EUT相对距离大于0.5时,相对误差能够保证在±1.5dB以内,可应用于实际混响室环境场强测试。

In order to solve the problem that the environment E-field intensity is difficult to measure when the radiation susceptibility test is carried out in the reverberation chamber,this article analyzes the statistical characteristics of E-field intensity in reverberation chamber,theoretically derives the representation of E-field's spatial correlation function in lossy reverberation chamber,then verifies the correctness of the representation by simulation analysis.From the representation,we can draw the conclusion that in lossy reverberation chamber the E-fields at two points whose distance is greater than half-wavelength are mutually independent.Therefore in E-field intensity measurement in reverberation chamber,the distance between measurement position and EUT should be greater than 0.5λ,which can be taken as a selection criterion.Finally,the method of combining numerical calculation with experimental verification is adopted to analyze the relationship between relative error and relative distance,and the criteria is verified.The relative error of distribution parameter(σ)at different relative distances is simulated and analyzed.It is concluded that the relative error can be decreased to±1.5 dB as long as the relative distance is more than 0.5,which can be applied to the actual environment E-field intensity test in reverberation chamber.