基于圆波导TE11模的模式简并特性和微波在椭圆波导中传输两个正交TE11模式相速不同的性质，研制了一种带有椭圆波导结构的圆波导TE11模圆极化器。该圆极化器通过圆波导到椭圆波导的过渡段，将输入的线极化TE11模式分成两个等幅、正交的TE11模，然后调整椭圆波导长度，使得两个正交的TE11模式的相位差为90°，实现了TE11模式微波线极化到圆极化的转换。利用时域有限差分软件优化设计了该圆极化器，并按照优化的结构尺寸加工了一套实验装置进行了实验测试，测试结果表明：在工作频率9～10 GHz范围内，该圆极化器轴比小于1 dB，驻波比小于1.1，且功率容量大于1.6 GW。

In this paper, a new type of circular polarizer is presented. Based on the characteristic of TE11 degenerate modes of circular waveguide and different phase velocities of long and short axes of elliptical waveguide, TE11 mode circular polarizer with elliptical waveguide is developed successfully. According to boundary conditions of microwave transmission, one incident TE11 mode is divided into two orthogonal TE11 modes with same magnitude. By adjusting length of elliptical waveguide, phase difference of two orthogonal TE11 modes is 90°, and conversion from linear polarization to circular polarization is realized. By FDTD software, circular polarizer is designed and optimized. Manufactured circular polarizer was measured by cold test and high-power microwave experiments. Theoretical and experimental results agree with each other. It is shown in experiments that axial ratio is less than 1 dB, VSWR is less than 1.1, phase difference about 90°, and power capacity above 1.6 GW is obtained at 9～10 GHz.