背脊波导移相器高次模特性及阻抗匹配问题

HIGHER MODE CHARACTERISTICS AND IMPEDANCE MATCHING PROBLEM OF RIDGED WAVEGUIDES

本文采用行波展开法[1] 精确计算出背脊波导移相器各阶模式的传播常数及对应的截止波长 ,指出背脊波导移相器虽然很难让所有高阶模式都截止 ,但可以通过调整设计参数减小高次模与主模的耦合。在阻抗匹配设计中提出把波导模式与平面波类比 ,运用平面波阻抗计算公式代替TE模波阻抗作为阻抗匹配的初值 。

Travelling wave expansion method (TWEM) was adopted to calculate the existing modes in ridged waveguide phase shifters and their cut off wavelengths. Though it was difficult to maintain single mode transmission in ridged waveguides, the coupling between base mode and higher modes may be ignored. A novel equivalent impedance of waveguides was obtained through comparison with plane wave, which is more suitable for matching problem than the conventional wave impedance for TE mode. In this way the efficiency of design was improved.