测量手征媒质特性的一种新方法

A New Approach to Chiral Media Measurement

常用的测量手征媒质特性的自由空间法和封闭结构法都有一些缺点．现提出采用金属介质波导（ＭＤＷ）的新方法．ＭＤＷ波导是一种过尺寸波导，但是，理论分析实验结果都表明，只要采用适当的ＴＥ１０－ＨＥ１１模转换器，ＭＤＷ波导中ＨＥ１１模的交叉极化电场分量很小，可以看作是线极化．同时，ＭＤＷ波导是方形波导．因此，可以用它来测量手征媒质的极化旋转特性．与常规波导法相比，ＭＤＷ波导法的样品尺寸可大五倍以上，因而更能满足实际测量要求，

Free--space and closed structure techniques are usually used in measuring chiral media. However, both methods have shortcomings. A new method using metal dielectric waveguide (MDW) is presented. The dimensions of the MDW may he more than five times those of conventional waveguide. The theoretical and experimental results show that the cross polarization components of HE,, mode in MDW are very small if one uses an effective TE_10-HE_11 mode transition. Therefore, this mode possesses an approximate linear polarization wave character. Meanwhile MDW has a square section; it can be used to measure the rotary dispersion of chiral media. MDW enables one to measure samples larger than the one in conventional waveguide, therefore beter meets the requirement of practical measurements.