利用模式匹配与四分量二维频域有限差分混合算法分析复杂截面波导不连续性

Analysis of Waveguide Discontinuities with Complex Cross Section by a Hybrid Mode Matching/4-Component 2-D FDFD Method

模式匹配(Mode Matching,MM)法分析波导不连续性问题时,通常需要已知相移常数和模式函数的解析表达式,因此,局限于分析简单截面波导不连续性问题.本文采用四分量二维频域有限差分(2-D FDFD)法能够有效地解决复杂截面波导本征模问题,本征值和本征向量分别对应相移常数和模式函数离散值,求得本征解后再利用模式匹配法计算出波导阶梯的广义散射参数.最后,给出了矩形波导中单脊膜片和十字膜片实例,验证了混合算法的准确性和高效性.

In analysis of waveguide discontinuities by the traditional mode matching（MM） method,the phase constant and the analytical expression of mode function must be required.This limitation makes the application of the method only suitable for waveguide discontinuities with simple boundary shapes.In order to determine the mode spectrum of complex shaped waveguide,an eigen equation is established using four-component two-dimension finite-difference frequency-domain（2-D FDFD） method.Phase constants and mode functions could be easily solved as eigen values and eigen vectors,respectively.Once the eigen problem was solved,the generalized scattering parameters can be calculated by the MM technique.Finally,demonstrations of a single-ridged iris and a cross-shaped iris are analyzed.The results show this hybrid method is correct and efficient.