# Microwave waveguide polarizer for satellite communication antennas with circular polarization

 1Piltyay, SІ, 1Bulashenko, АV, 1Polishchuk, АV, 2Bulashenko, ОV1National Technical University of Ukraine «Igor Sikorsky Kyiv Polytechnic Institute», Kyiv, Ukraine2Ivan Kozhedub Shostka Professional College of Sumy State University, Sumy, Ukraine Space Sci. & Technol. 2022, 28 ;(3):04-04 Publication Language: Ukrainian Abstract:  The volumes of information transmitted in modern satellite telecommunication systems are constantly increasing. Antennas with signal polarization processing, which is performed by polarizers, are the fundamental elements of such systems. Therefore, the development of methods for the analysis of new polarizers is an important problem. From a technological point of view, polarizers based on waveguides with irises are the simplest. Analysis and optimization of electromagnetic characteristics of a polarizer based on a square waveguide with irises are the goals of the presented research.       To solve this optimization problem, we have created a new mathematical model, which allows investigating the influence of the design parameters of the polarizer on its electromagnetic characteristics. A mathematical model of the waveguide polarizer with irises was created by the method of decomposition using wave transmission and scattering matrices. Besides, the new mathematical model takes into account the thickness of the irises using their equivalent T- and П-shaped substitution circuits. The general wave scattering matrix is the basis of a new mathematical model of a waveguide polarizer. This matrix was determined using the theory of microwave circuits. The main characteristics of the waveguide polarizer were determined through the elements of this matrix. Here, we perform the optimization of the polarizer characteristics in the Ku-band 10.7–12.8 GHz.       The developed new mathematical model of a waveguide polarizer with irises makes it possible to take into account the heights of the irises, distances between them and their thickness. The new mathematical model determines the electromagnetic characteristics of the polarizer in a simpler and faster way compared to the finite integration technique, which is often used for the analysis of microwave devices for various purposes. Keywords: axial ratio, crosspolar discrimination, diaphragm, differential phase shift, iris, polarizer, scattering matrix, transfer matrix, voltage standing wave ratio, waveguide