圆突-矩形波导中截止波长及场的近似解

THE CUTOFF WAVELENGTH AND APPROXIMATE SOLVED FIELDS OF A CAM RECTANGULAR WAVEGUIDE

介绍用边界元素法计算圆突－矩形波导的截止波长的过程和表达式，根据场分量满足理想金属波导壁的边界条件构造场的一种近似解通用表达式，结合变分法确定公式中幂函数的实指数，得到主模场结构的具体公式。在Ｘ波段对不同波导尺寸，利用文中公式计算了截止波长。

The process and expressions for calculating the cut off wavelength of camrectangular waveguide are discussed by using boundary element method (BEM). An approximate general field expression for the dominant mode, where the real exponent of the power function is found with the variational method, is built according to field components fitting the boundary condition of completely conducting metal waveguide. Then the approximate expressions can be found. The cut off wavelengths and the exponent constant for the different dimensions of the guide in X band are computed .