Anotace:
One of the fundamental problems of modern digital telecommunications is the economy of digital information and frequency resources, which are highly limited. The introduction of novel telecommunication systems and 5G networks requires the search of principal solutions for economy and reusing of frequency spectrum. Therefore, modern wireless mobile, terrestrial and satellite systems use variety of new technologies to increase the information capacity of communication channels for the economy of limited frequency resources. One of the most effective ways to reuse the operating frequency band of the information system is to apply antennas with polarization signal processing. Such systems provide the possibility to transmit and to receive simultaneously signals with different types of polarization. Consequently, the application of electromagnetic waves with two orthogonal polarizations improves the information characteristics of wireless systems for various purposes. This allows to double the information capacity of mobile, terrestrial and satellite communication channels. In addition, polarization processing is carried out in meteorological and radar systems for receiving, transmitting and processing of information. The essential elements of such systems are microwave polarizers and orthomode transducers. The electromagnetic characteristics of these devices affect greatly the characteristics of the whole system. Main electromagnetic characteristics include phase, matching and polarization parameters. The article presents the results of development of a compact tunable polarizer based on a square waveguide with three posts. The developed polarizer operates in the X-band from 8.0 GHz to 8.5 GHz. Created mathematical model of the polarizer is based on the scattering and transmission matrices. To verify correctness of the developed theoretical model the calculation of all characteristics was also performed numerically using the finite integration technique. The developed compact polarizer based on a square waveguide with three posts allows to tune its matching and polarization characteristics by changing the heights of all posts. The main advantages of the developed polarizer are small dimensions, the tuning option and stability of characteristics of polarization transformation.