对同轴波导内传输TEM模时金属支撑杆的散射特性进行了研究.通过将同轴波导等效为窄边是磁壁的矩形波导,建立了金属支撑杆的散射场计算模型,用积分方程法得到了散射场的计算公式,其计算结果与有限元方法仿真结果吻合良好.分析计算和实验表明:当同轴波导传输TEM模时,n根角向均匀分布的支撑杆在同轴波导内激励起一系列TE_(mn)1模式;当n大于同轴波导截面平均周长与波长之比时,金属杆所激励的高阶模截止,输出和反射模式仅为TEM模,其反射系数随支撑杆根数或支撑杆半径的增加而增大,随频率的升高而减小.

This work focused on the metal posts' scattering calculation and design in coaxial waveguide (CWG), which are useful in many high-power microwave devices. The calculation model was constructed by equating CWG with rectangular waveguide. The scattering formula was deduced by Integral Equation Method, which was validated by Finite Element Method. The calculation and experiment results show that the posts will excite a series of TE_(mn)1 modes in CWG when TEM mode is inputted. While the number of the posts is greater than the ratio of the CWG's average perimeter to wavelength, all of the TE_(mn)1 modes are evanescent, with only TEM mode being outputted. The reflection coefficient of TEM mode increases with number or radius of the posts, and is in inverse proportion to frequency.