为了验证频率搅拌的有效性,论述了混响室的特征参数和频率搅拌的关键参数,并对频率搅拌的有效性进行了简要的理论分析。运用FEKO软件进行了建模仿真,依据场均匀性容差标准检验了场均匀性,采用假设检验方法研究了统计特性。设置对比试验,测量了某混响室在机械搅拌和频率搅拌这2种方式下的最低可用频率。结果表明:中心频率厂-150MHz时总体标准偏差σ1=2.71dB,f=200MHz时σ1=2.27dB,场均匀性符合标准规定的容差要求,且仿真结果符合理论分布的统计特性;随着频率升高,场均匀性和统计特性都会改善;试验得出在机械搅拌和频率搅拌方式下混响室的最低可用频率大致相同,机械搅拌方式下场均匀性更好一些。从而验证了采用扫频方式实现频率搅拌的有效性,为进一步研究频率搅拌奠定了基础。
In order to prove the validity of frequency stirring (FS), we analyzed the theory of FS briefly, and discussed the characteristic parameters of reverberation chamber, as wetl as the key parameters of FS. Based on simulation with a model established in the software FEKO, the field uniformity was tested according to its tolerance requirements. Then, using hypothesis testing methods, we studied the statistical characteristics of FS. Finally, we measured the lowest available frequency of a reverberation chamber working in mechanical or frequency stirring through tests. The results show that, when the operating center frequency f is 150 MHz and 200 MHz, the total standard deviation σ1 would be 2.71dB and 2.27 dB, respectively. The field uniformity satisfies the requirements of tolerance prescribed in standards, and the simulation agrees with the statistical characteristics of the theoretical distribution. Both field uniformity and statistical properties are improved with increasing frequency. Experiments show that the lowest available frequency of a reverberation chamber working in mechanical stirring is similar to that in FS, while the mechanical stirring achieves better uniformity. These results together verify the effectiveness of FS through sweeping.