Abstract

This article presents results of optimization and development of X-band square waveguide stepped-thickness septum polarizers. Electromagnetic characteristics of the polarizers were simulated and optimized numerically using finite elements method. Optimal dimensions of the 2-, 3-, and 4-section stepped-thickness septum polarizers for various fractional bandwidths have been obtained. It is demonstrated that application of the stepped-thickness septum with 3 sections instead of it constant-thickness counterpart improves return loss and cross-polarization discrimination of the septum polarizer by 2–6 dB and 3–6 dB respectively, depending on fractional bandwidth. A prototype of the optimal waveguide polarizer with 3-section stepped-thickness septum configuration for the operating frequency range 7.70–8.50 GHz was developed, manufactured and tested. Measured values of VSWR and cross-polar discrimination of the prototype together with necessary transitions and bends within the stated above frequency range are less than 1.4 and higher than 30 dB, respectively. The developed compact stepped-thickness septum polarizer is a good candidate to be applied in the quasi-monopulse dual-circular polarization feed system of the ground station reflector antenna for tracking earth observing satellites.

中文翻译：

---

X波段波导阶梯厚度隔膜偏振器的优化设计

摘要

本文介绍了 X 波段方形波导阶梯厚度隔膜偏振器的优化和开发结果。使用有限元方法对偏光片的电磁特性进行了数值模拟和优化。已获得 2、3 和 4 节阶梯厚度隔膜偏振器的最佳尺寸，适用于各种分数带宽。结果表明，根据分数带宽，应用具有 3 个部分的阶梯厚度隔板而不是恒定厚度的隔板可将隔板偏振器的回波损耗和交叉极化鉴别分别提高 2-6 dB 和 3-6 dB。开发、制造和测试了工作频率范围为 7.70–8.50 GHz 的具有 3 节阶梯厚度隔膜配置的最佳波导偏振器的原型。在上述频率范围内，样品的 VSWR 和交叉极化鉴别以及必要的过渡和弯曲的测量值分别小于 1.4 和高于 30 dB。研制的紧凑型阶梯式厚度隔膜偏振器可很好地应用于地面站反射器天线的准单脉冲双圆极化馈电系统，用于跟踪地球观测卫星。