Інститут Шосткинський (ШІ)
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Item Mathematical Model of a Square Waveguide Polarizer with Diaphragms(Journal of Microwaves, Optoelectronics and Electromagnetic Applications, 2021) Булашенко, Андрій Васильович; Bulashenko, Andrii Vasylovych; Piltyay, S.; Bulashenko, O.The development of new mathematical model for guide polarization converter with diaphragms was carried out in the research by the method of wave matrices. In addition, numerical modeling of the performance of a polarizer with diaphragms is made by simulating the propagation of the fundamental modes with perpendicular linear polarizations. The wave matrix model was obtained by splitting the polarizer into separate structural elements. Each element was described by its own wave transmission matrices. As a result, a general wave scattering matrix was formed. Based on the elements this matrix the electromagnetic characteristics of the considered polarizer were obtained theoretically. In particular, complex reflection and transmission coefficients were calculated. Their modules and phases were analyzed in the frequency interval 10.7–12.8 GHz. To check the correctness of the obtained results an independent numerical simulation was carried out applying the finite element methodology in the frequency interval. The results of both approaches are in good agreement. The engineered converter of polarization with four diaphragms provides a reflection coefficient modulus of less than 0.14 and a transfer coefficient modulus of more than 0.99 for two orthogonal types of polarizations. As a result, a rigorous mathematical method was developed to analyze the elements of the scattering matrix of a waveguide polarizer with diaphragms. It can be used for the development of new broadband waveguide polarizers and waveguide filters based on diaphragm elements.Item Electromagnetic Simulation of New Tunable Guide Polarizers with Diaphragms and Pins(Advanced Electromagnetics, 2021) Piltyay, S.; Булашенко, Андрій Васильович; Bulashenko, Andrii Vasylovych; Shuliak, V.; Bulashenko, O.In this article we present the results of electromagnetic simulation, development and optimization of a guide polarizer with a diaphragm and pins. An original mathematical model was obtained using the wave matrix approach for a guide polarizer with one diaphragm and two pairs of pins. The discontinuity elements were modeled as inductive or capacitive conductivities for two kinds of linear perpendicular polarizations of the electromagnetic waves. The theoretical model is based on wave scattering and transfer matrices. The total matrix of a polarizer was developed using wave matrices of transmission of separate elements of a polarizer’s structure. Using elements of the general S-parameters the electromagnetic characteristics of a considered polarizer were obtained. In order to test the performance of a suggested mathematical model, it was simulated in a software based on the finite elements method in the frequency domain. The presented design of a polarizer is adjustable due to possibility of mechanical tuning of the heights of applied pins. Considered guide polarizer with one diaphragm and two pairs of pins provides a reflection coefficient of less than 0.36 and a transmission coefficient of more than 0.93 for both linear perpendicularly polarized modes. Therefore, a new theoretical technique was developed in the research for fast electromagnetic simulation of wave matrix elements of a guide polarizers with diaphragms and pins. Developed simulation approach can also be widely used for the development of new tunable guide filters, polarizers, rotators and other microwave components with diaphragms and pins.Item Electromagnetic Performance of Waveguide Polarizers with Sizes Obtained by Single-Mode Technique and by Trust Region Optimization(Advanced Electromagnetics, 2022) Piltyay, S.; Bulashenko, A.; Kalinichenko, Y.; Bulashenko, O.V.Modern wireless networks, stationary terrestrial and satellite systems use many modern technologies to increase communication channels information capacity. They save limited frequency resources. In satellite communications the polarization signal processing is applied to reuse the allocated frequency bands. Usage of circularly polarized electromagnetic waves, which transmit useful signals, reduces fading effects and eliminates disadvantages introduced by multipath propagation interferences. In this case the distortion levels for signals with an odd number of electromagnetic waves reflections in the receiving antenna systems will be reduced down to the thresholds of their cross-polarization isolation. Besides, in the case of orthogonal polarizations usage, the achieved information capacity of the applied wireless communication channel multiples almost by the factor of two. The type of polarization of the used electromagnetic wave strongly determinates the peculiarities of the process of its propagation in the space or transmission line. Polarization signal processing is frequently carried out in horn feed systems of the reflector antennas. Such feed networks and systems allow to transmit and receive signals with several kinds of polarization at the same time. The fundamental element of dual circular polarization antenna feed networks is a waveguide polarization duplexer. The phase, isolation and matching characteristics of a polarization converter strongly influence on the functionality and polarization discrimination possibilities of the entire reflector antenna system. Therefore, the development and optimization of the characteristics of waveguide polarizers for satellite communication antennas is a crucial technical problem, which must be solved by fast and accurate methods. The comparison of electromagnetic performance of waveguide polarizers with sizes obtained using a fast single-mode technique and by more accurate trust region optimization method is carried out in this research. The results for differential phase shift, level of voltage standing wave ratio, ellipticity coefficient and cross-polarization discrimination are shown and discussed.Item Accuracy and Agreement of FDTD, FEM and Wave Matrix Methods for the Electromagnetic Simulation of Waveguide Polarizers(Advanced Electromagnetics, 2022) Bulashenko, A.; Piltyay, S.; Polishchuk, A.; Bulashenko, O.; Kushnir, H.; Забегалов, Ігор Вікторович; Забегалов, Игорь Владимирович; Zabehalov, Ihor ViktorovychWaveguide devices of polarization processing are key elements of modern dual-polarized antenna systems. Such antenna systems carry out polarization transformation and separation of signals with orthogonal polarizations in satellite communications and radar appliances. Well-known electrodynamic methods are used to simulate performance of such devices. This paper investigates the accuracy and mutual matching of wave matrix method with FDTD and FEM. The wave matrix method is based on the theory of scattering and transmission matrices. The main electromagnetic characteristics of a polarizer were obtained through the elements of these matrices. The main characteristics of a polarizer were compared. They include phase difference of orthogonal polarizations, level of voltage standing wave, ellipticity coefficient and level of cross-polarization isolation. Comparison of electromagnetic characteristics was carried out at the example of a waveguide iris polarizer for the operating frequency range from 13.0 to 14.4 GHz. In addition, the process of optimization of electromagnetic characteristics was carried out by changing the geometric dimensions of a polarizer. Calculated by different theoretical methods characteristics were compared and analyzed. Results, which were obtained by considered methods, are in good agreement.Item Compact 2-step Septulum Polarization Converters for Radars and Satellite Systems(Advanced Electromagnetics, 2022) Piltyay, S.; Bulashenko, A.; Fesyuk, I.; Bulashenko, O.This article presents the results of analysis, numerical simulations and optimization of new narrowband guide septulum polarization converters. Orthomode duplexers and polarization converter designs based on septulums are widely used in modern microwave systems with orthogonal circularly polarized signals. Septulum guide polarizer is an effective compact device, which transforms right-hand circularly polarized (RHCP) and left-hand circularly polarized (LHCP) electromagnetic modes into linearly polarized ones. At the same time, it divides RHCP and LHCP modes and directs them to two different rectangular guides with high signal discrimination to each other. Thus, a septulum-based guide device integrates performance of a polarization transformer and of an orthomode duplexer. The main electromagnetic characteristics of the suggested polarization converter were simulated using the finite elements method. The proposed design of a compact narrowband guide polarization converter has a septulum with two steps. Several designs of septulum polarization converters were developed and compared for different relative bandwidths of 5%, 10%, and 15%. The comparative investigation of the obtained designs was carried out. Main electromagnetic characteristics of optimal septulum polarization converters were modeled and compared in considered fractional bandwidths. These include reflection coefficients, cross-polarization discrimination, ellipticity parameter, and ports discrimination. Developed compact septulum polarization converters can be applied in modern antenna systems for radars and satellite communication systems.