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Today polarization-processing devices are widely used in satellite information systems. Waveguide polarizers are the key element of antenna systems used to convert signal polarization from linear to circular type and vice versa. The circularly polarized signals have many significant advantages over the signals with other types of polarization. Consequently, simultaneous application of polarizers with other radio signal processing devices highly increases the efficiency of new satellite information and telecommunication systems for various purposes, wireless data transmission systems, mobile communication systems, radar systems and medical diagnostic systems. In this article, we have developed a new matrix technique for the calculation of parameters and characteristics of a polarizer based on a square waveguide with three irises, which are inductive or capacitive loads depending on the wave's polarization. Based on the theory of microwave circuits, the analytical expressions of the general wave scattering matrix were derived using the transmission and scattering wave matrices of elements of a polarizer structure. As a result, the main characteristics of the polarizer were obtained: differential phase shift, voltage standing wave ratio for vertical and horizontal polarizations, axial ratio and cross-polar discrimination. The presented method makes it possible to study the influence of the polarizer dimensions, such as the heights of the irises and the distances between them, on its main characteristics. Obtained analytical model makes it possible to find theoretically optimal sizes, which provide the required polarization characteristics of the device with the best matching in the operating frequency band. In addition, the developed wave matrix technique can be applied for further optimization using the specialized programs for microwave device simulation.

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A novel design of the polarizer based on a square waveguide with four posts and four irises for Ku‐band 10.7–12.8 GHz is proposed. The main advantage of the developed polarizer design is the option to tune its polarization characteristics by variation of the posts height. The equivalent circuit of the polarizer has been obtained using scattering and transfer matrices technique. Using this model, the polarization and matching characteristics of the suggested polarizer were optimized simultaneously using the trust region method. This method is reliable and robust since it provides good convergence properties. The novelty of this study lies in the use of a new waveguide polarizer structure based on a combination of irises and posts. Posts enable fine‐tuning of the polarizer performance, while irises promote wide operating frequency band. The following simulated characteristics of the optimal polarizer design were obtained: VSWR for the main modes of horizontal and vertical polarization is less than 1.47, the differential phase shift is within 90° ± 2.6°, the axial is less than 0.46 dB, and the XPD is higher than 32 dB in the operating frequency range. A developed polarizer can be applied in antenna feeds for satellite communication and radar systems.

At the present day, antennas and signals with dual or single circular polarizations are widely used in modern satellite telecommunication systems, television systems, satellite navigation systems, civil and military radars, mobile communication systems, wireless identification systems and wireless data networks. The widespread application of signals with circular polarizations is caused by their advantages over signals with polarization of other types. The key element of antenna systems with circular polarizations is a polarizer. It is a microwave device, which performs the transformation of the circularly polarized electromagnetic waves into the linearly polarized waves or vice versa. The combination of a polarizer and an orthomode transducer in the antenna feeds carries out the full conversion of two signals with orthogonal circular polarizations and their transmission to the isolated waveguide ports. This article presents results of the development, optimization and analysis of new designs of compact polarizers based on a square waveguide with irises. The characteristics of polarizers with different number of irises have been optimized for the operation in Ku-band 10.7-12.8 GHz. The electromagnetic characteristics of the waveguide polarizers were simulated and optimized using finite integration technique. The evolution of sizes of optimal polarizer designs and improvement of their performance have been analyzed for the polarizers with 3 and 4 irises. The better characteristics among the investigated waveguide iris polarizer designs are provided by the polarizer with 4 irises. Developed compact square waveguide polarizer with 4 irises provides highlyefficient performance in the operating Ku-band 10.7-12.8 GHz and can be widely used in modern antenna feeds for satellite information systems.