耦合微带线的散射参数特性分析

针对耦合微带线的散射参数在一些频率点处呈现出波峰、波谷现象，该文根据微波网络理论，从两根平行微带线的奇模和偶模的散射参数出发，推导出四端口网络散射参数的波峰、波谷处频率与并行长度和线间距的关系。同时分别在频域和时域研究了两根平行微带结构的插入损耗对信号传输的影响。经分析发现，由于微带线间的耦合，波峰、波谷处的频率随线间距增大而提高，随长度增大而降低；而且在串扰产生的同时，所传输的信号也有一定程度的衰减。

Analysis of Characteristic of Scattering Parameter for the Coupled Microstrip Lines

For crests and troughs exiting in the scattering parameters of the coupled microstrip lines, the relation between the frequencies where crests and troughs occur and the parallel length, space between lines for the four-port network is deduced from scattering parameters of the odd mode and even mode based on microwave network principle. Effect on the transmitted signal by the insertion loss for the structure of two parallel microstrip lines is also studied in frequency domain and time domain respectively. Due to the coupling between microstrip lines, it is shown that the frequencies where crests and troughs occur increase with the space between lines but reduce with the parallel length, and the transmitted signal is attenuated when crosstalk is induced.