弯波导的本征模与角传播常数

本文采用严格的本征模表示矩表截面均匀弯曲波导中的场，文中给出了虚阶Ｂｅｓｓｅｌ函数及其导数的计算公式和计算方法，由此完整地解决了任意半径弯波导本征征模及角传播常数的精确计算问题，典型数值计算结果表明，弯波导中的本征模与直波导中的本征模具有一一对应关系，变波导的等效传播常数与直波导的传播常数在数值上相当接近，模场的径向分布则呈衰减的驻波形式。

Eigenmodes and Angular Propagation Constants in Curved Waveguides

The fields in continuously curved waveguides of rectangular cross section are represented in terms of the exact eigenmodes. The formulas and numerical methods for computing Bessel functions of imaginary orders are presented,and the problem of computing eigenmodes and their angular propagation constants in curved waveguides of arbitrary curvature with high precision,is therefore completely solved. Typical numerical results are given. It is shown that there is a one-to-one correspondence between the eigenmodes in curved guide and the corresponding modes in staight guide, and that the equivalent propagation constants for curved guide close numerically to the propagation constants for staight guide,while the radial distribution of the modal fields is in an attenuated standing-wave form.