基于材料反射率谐振特性测试电磁参数的自由空间法

A novel free-space method of mearsuring of electromagnetic parameters based on the resonance property of reflectivity

自由空间法具有非接触、非破坏性测试特点,适于材料的电磁参数测试.根据材料反射率扫频测试的特性,提出了一种基于谐振特性测试材料电磁参数的新的自由空间法.通过理论分析,研究了发生相消和相长干涉的条件,给出了应用干涉位置和材料厚度测试材料介电常数实部的理论计算公式.利用谐振峰/谷的位置及其相互关系可以计算材料介电常数虚部,而利用波谷比值法比驻波比值法容易达到更高的计算精度.

The free-space method is a analysis method applicable for measuring electromagnetic parameters of materials, owing to its non- contact and non-destructibility. Base on the resonance property of reflectivity under sweep frequency mode, a novel free-space method is presented. For the study of constructive interference or destructive interference, the method is used to measure the real component of complex dielectric constant through the thickness of material and the interference frequency. The method can also measure the imaginary component of complex dielectric content by the positions of peaks and valleys of waveform or/and their correlation. The study also demonstrates the higher precision obtained by using the valley-to-valley ratio than by using the standing waveform ratio （peak-to-valley ratio）.