频率搅拌混响室场均匀性与搅拌带宽选取方法分析

为了确定混响室在频率搅拌方式下的有效搅拌带宽这一参数,在分析矩形谐振腔原理的基础上,简要阐述了频率搅拌混响室实现电场"统计均匀"的工作原理,并进一步对搅拌带宽的选取原则进行了分析。在尺寸为10.5m×8m×4.3m的大型混响室内,通过矢量网络分析仪测量了少模与过模状态下收、发天线间的传输参数S21,利用测得的S21参数分析了该混响室在频率搅拌方式下的低频特性,并给出了不同搅拌带宽下场均匀性验证的方法。试验结果及数据处理表明:该混响室在频率搅拌方式下最低可用频率与机械搅拌方式基本相同;在过模状态下,选择合适的搅拌带宽能够得到统计均匀的场环境;当工作频率为500MHz～1.5GHz时,其最小有效搅拌带宽约为30MHz。

Analysis of Field Uniformity and Stirring Bandwidth in Frequency Stirring Reverberation Chamber

In order to determine the effective stirring bandwidth of a frequency stirring reverberation chamber,we briefly described the operational principle of realizing the electric field uniformity for frequency stirring reverberation chamber on the basis of the analysis of rectangular resonant cavity,and further analyzed the principle of stirring bandwidth selection.The parameter S21 between transmitting antenna and receiving antenna was measured by the vector network analyzer when the chamber with the dimension of 10.5 m×8 m×4.3 m was in multi-mode and few-mode.The chamber’s feature at low frequency was analyzed by the value of S21,and the validation method of field uniformity under different stirring bandwidths was given.The results of the examination and processed data show that the lowest usable frequency in frequency stirring mode is similar to that in mechanical stirring reverberation chamber,and the uniformity electrical field in multi-mode can be achieved with the correctly chosen stirring bandwidth.When the range of operating frequency is from 500 MHz to 1.5 GHz,the chamber’s minimum effective stirring bandwidth is approximately 30 MHz.