Analytical Method of Constructive Synthesis of Compact Polarizers with Maximally Flat Phase-Frequency Characteristic Based on Two Reactive Elements in Square Waveguide

Abstract

The paper proposes a developed approximate analytical method of constructive synthesis of compact polarizers based on two reactive elements in a square waveguide. The analytical synthesis was carried out under conditions of the absence of reflection and obtaining a required phase shift. As a result, simple formulas have been derived that determine parameters of phase-shifting elements and the electrical distance between them. The constructive synthesis was performed under conditions of the equality of required and real admittances of posts and diaphragms in a square waveguide and their derivatives at the central frequency of the working frequency band. As a result, the real geometrical dimensions of polarizers based on two posts and based on two diaphragms in a square waveguide were determined that provided for maximally flat phase-frequency characteristic. It has been shown that the polarizer based on two posts in a square waveguide can ensure the working frequency band of 4% or 13% while reflecting the electromagnetic energy of less than 1% or 10%, respectively, and differential phase shift Δφ = 90°±1°. However, polarizer based on two diaphragms in a square waveguide under the same conditions can ensure the working frequency band of up to 11% or 18%, respectively. The theoretical results were confirmed by experimental data.