用两次反射法同时测量微波频率下的复介电常数和导磁率

Measuring the Complex Permittivity and Permeability simultaneously under Microwave Frequencies with twi-Reflection Technique

在短路开路法及准开路短路法的基础上,本文提出了两次反射法.用它来测量微波频率下的复介电常数和导磁率可以有更小的误差.因为它除了能选择最佳的样品厚度L_e外,还可以选择最佳的短接传输线长度L_1和L_2.另外可以避开某些特大或特小的驻波比,以增加测量的范围和精度.用一般的仪器设备,通过优化选择L_1,L_2和L_e,可以使ε’和μ’的测量误差在±5％以内,tgδe的测量误差在±25％以内。tg6m的测量误差在土15％以内.对结果的分析表明.最大的误差源来自于驻波比p的测量误差.本方法适用于微波吸收材料和一般非低损耗材料的ε_r和μ_r的测量.

Based on the short-open-end and the quasi-open-short-end techninque, a twi-reflection technique is suggested to measure ε r and μ r. It can make the measurements more accuracy because not only the specimen thickness can be chosen properly, but also the transmission-end lines' length can be chosen. It is shown by analysing, calculating and practical measuring that the errors are usually limited within ± 15% for ε' and μ', and errors can be controlled within ± 25% for tgδ e, and ± 15% for tgδm by chosing the specimen thickness and the transmission-end lines' length. It is also shown that the greatest error resource is the measurring error of stationary wave ratio. This technique is effective for measuring εr and μ r of concealing material and usual lossy substances.