Abstract

This paper proposes an approximate analytical and numerical constructive synthesis method of optimal waveguide polarizers based on three irises in square waveguide. A mathematical model of polarizer has been developed on the basis of waveguide transmission and scattering matrices. The analytical expressions derived for elements of the scattering matrix were used for determining the electrical characteristics of polarizer. The synthesis conditions were developed in the form of a system of equations, the solution of which should ensure the minimal deviation of the differential phase shift with respect to 90°, the maximum possible flat phase frequency characteristic, and the best matching in the specified frequency band. The method was evaluated on the constructive synthesis of polarizers for three working frequency bands: 7.25–8.6, 7.75–8.5, and 8.0–8.5 GHz. The validity of constructive synthesis results was confirmed by the calculation data of characteristics of synthesized polarizers using the finite element method in frequency domain employing the CST Microwave Studio Software. A satisfactory matching of electrical characteristics calculated by both methods was achieved. For the working frequency band of up to 10%, the proposed method of constructive synthesis ensures a sufficient for practical purposes accuracy in determining the dimensions of polarizer and the corresponding electrical specifications. This method can be also recommended for rapid determination of initial values of polarizer dimensions guaranteeing the operation in the vicinity of global optimum and thereby speeding up the designing of optimal polarizers at the electrodynamic level. In addition, this method can be extended to the constructive synthesis of waveguide polarizers with a large number of irises.

中文翻译：

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基于方波波导三虹膜的最优偏振器构造合成的解析与数值方法

摘要

本文提出了一种基于方波导中三虹膜的最优波导偏振器的近似解析和数值构造合成方法。偏振器的数学模型已经建立在波导传输和散射矩阵的基础上。散射矩阵元素的解析表达式用于确定偏振器的电特性。综合条件以方程组的形式开发，其解应确保微分相移相对于 90°的最小偏差、最大可能平坦的相位频率特性以及在指定频率下的最佳匹配乐队。该方法在三个工作频段的偏振器的建设性合成上进行了评估：7.25-8.6、7.75-8.5 和 8。0–8.5 GHz。使用CST Microwave Studio软件在频域中使用有限元法计算合成偏光片特性的计算数据，证实了构造合成结果的有效性。两种方法计算出的电气特性都达到了令人满意的匹配。对于高达 10% 的工作频带，所提出的结构性合成方法可确保在确定偏振器的尺寸和相应的电气规格方面具有足够的实用精度。这种方法也可以推荐用于快速确定偏振器尺寸的初始值，保证在全局最优附近的操作，从而加快电动级最佳偏振器的设计。此外，