边界条件微扰法计算非理想波导的传播常数

Calculation of the Propagation Constants in Waveguides with Imperfect Conductor by the Perturbed Boundary Condition Method

考虑到非理想导体波导壁金属损耗对传播常数的影响,对理想金属边界条件进行一阶近似微扰,得到了非理想波导的传播常数。和传统微扰法相比,能够在截止频率附近较为精确地计算衰减常数,也适用于导体损耗较大的情况;同时能给出非理想导体波导壁对相位常数的影响。将结果与Ansoft HFSS软件的仿真结果进行比较,两者具有较好的一致性。同时给出了边界条件微扰法解与解析解及传统微扰法解在一定条件下的联系,表明边界微扰法比解析法实现简单,比传统微扰法具有更广泛的适用性。

Considering the effect on the propagation constants of waveguide with imperfect conductor walls,the first-order approximating perturbation to the perfect conductor boundary condition is demonstrated and the propagation constants of waveguide with finite conductivity are derived.Comparing with the conventional perturbation method,the attenuation constants are more accurate in the vicinity of cutoff frequency,and the present method is also suitable for the waveguide with large conductor loss.In addition,the effect on the phase constants and the shift of cutoff frequency due to the metal loss can be obtained.The numerical results are consistent with the simulation results by Ansoft HFSS.Theoretical analysis proves that under certain conditions,the solutions of the perturbation boundary condition method are approximately consistent with the analytical solutions and the solutions of the conventional perturbation method.However,the present method is easier to implement than the analytical method,and is more accurate and extensive in application than the conventional perturbation method.