Technique of Mathematical Synthesis of Waveguide Iris Polarizers

Authors A.V. Bulashenko1 , S.I. Piltyay1 , I.I. Dikhtyaruk1 , O.V. Bulashenko2

1National Technical University of Ukraine “Igor Sikorsky Kyiv Polytechnic Institute”, 37, Peremohy Ave., 03056 Kyiv, Ukraine

2Ivan Kozhedub Shostka Professional College of Sumy State University, 1, Institutskaya St., 41100 Shostka, Ukraine

Issue Volume 13, Year 2021, Number 5
Dates Received 16 April 2021; revised manuscript received 20 October 2021; published online 25 October 2021
Citation A.V. Bulashenko, S.I. Piltyay, et al., J. Nano- Electron. Phys. 13 No 5, 05024 (2021)
PACS Number(s) 84.40.Az, 84.40.Ua
Keywords Electromagnetic simulation, Microwave engineering, Waveguide components, Synthesis of microwave devices, Scattering matrix, Transmission matrix, Polarizer, Waveguide polarizer, Iris polarizer, Circular polarization.

In this article, we have developed a new mathematical technique for synthesis of waveguide iris polarizers with optimal phase and matching characteristics. The technique applies theoretical single-mode expressions of the differential phase shift between the waves with orthogonal linear polarizations and of the voltage standing wave ratio to optimize the geometrical dimensions of the polarizer’s structure. These expressions were combined into a set of mathematical conditions to obtain the required values of characteristics. The proposed technique was implemented to synthesize a waveguide polarizer with two thin conducting irises. Such irises are equivalent to inductive or capacitive loads in a waveguide transmission line, depending on the polarization type of the fundamental electromagnetic mode. The mathematical model of the waveguide iris polarizer was developed based on the equivalent wave matrices. As a result, the main electromagnetic characteristics were determined through the elements of the polarizer’s scattering matrix. Suggested analytical synthesis technique allows to find all optimal geometrical dimensions of the iris polarizer including the transversal sizes of a square waveguide, the heights of the irises and the distances between them. Variation of these dimensions allows to obtain the required electromagnetic characteristics of microwave waveguide devices, namely the optimal matching and cross polarization level in the operating frequency band. The differential phase shift of 90° ± 0.5° was obtained for the square waveguide iris polarizer optimized for the operating satellite frequency band 8.0-8.5 GHz. The voltage standing wave ratio does not exceed 2 for the fundamental modes of vertical and horizontal linear polarizations. The crosspolarization level of the iris polarizer is less than − 34 dB. The axial radio does not exceed 0.4 dB. Therefore, the presented mathematical method for single-mode synthesis of waveguide polarizers with diaphragms can be used to initially optimize them before the application of specialized programs for simulation of microwave devices. In addition, the suggested technique of mathematical synthesis can be widely used for the development of new microwave polarizers, phase shifters and filters based on irises and posts in waveguides.

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