Dual-Band Irradiation System of Ka/Q Band for Satellite Communication Station

Introduction. Due to the depletion of the frequency resource in the Ku frequency range, satellite communication systems are being actively developed in higher frequency ranges, i.e., Ka and Q. Satellite communication earth stations in these ranges are characterized by receiving and transmitting at widely spaced frequencies (1.5 times or greater). Mirror antennas used in communication stations must ensure the formation of appropriate radiation patterns in two separated ranges. Therefore, due to the high requirements for their technical characteristics, the development of feeds for such antennas is associated with a number of currently unresolved difficulties. Aim. Development of models and prototyping of a dual-band feed based on a coaxial circuit and a feeder path using a narrow-band transition from a rectangular waveguide to a round one. Materials and methods. Calculation and research of the developed design of a dual-band irradiation system was carried out using the CST Studio Suite software and specially developed add-on programs that significantly simplify and speed up the work. Results. A prototype of the dual-band feed EIF5.468587.001 was developed, which ensures the formation of the radiation pattern of a mirror antenna in the receiving range (19.172…19.792 GHz) with an efficiency of no less than 46 dBi and the level of the first side lobe of no more than 20.1 dB, and in the transmitting range (43.924...44.524 GHz) with an efficiency of no less than 52.7 dBi and a first side lobe level of no more than 16.7 dBi. A comparative analysis of the developed feed model with a serial sample as part of the 08150.6220-0 antenna of a satellite communications earth station was carried out. Conclusion. The EIF5.468587.001 feed produced as a result of the work makes it possible to form an axisymmetric pattern of a mirror antenna with a higher efficiency (by 0.7 dBi in the receiving mode and 1.4 dBi in the transmitting mode) and with the lowest level of off-axis radiation compared to the feed manufactured by JSC ISS as part of the 08150.6220-0 antenna and currently used as part of a satellite communication station.