Abstract
This paper discusses the modernization of a ground station antenna with a parabolic reflector of 3.7 m diameter for operation in the S- and X-bands. The main focus is on accounting for the actual reflector geometry, which was reconstructed based on high-precision laser measurements. Using the obtained data, a new dual-band coaxial feed was developed, ensuring the alignment of phase centers in the S- and X-bands and high port isolation. The antenna design optimization and performance prediction were carried out using electromagnetic modeling in Ansys HFSS, taking into account the actual parabolic profile. The fabricated prototype underwent laboratory testing, which confirmed the simulation results. The beamwidth was approximately 0.7o , the aperture efficiency reached 56%, and the gain-to-noise temperature ratio (G/T) was about 25.9 dB/K, meeting the requirements of the radio link for receiving signals from low-orbit satellites. The results demonstrate that accurate consideration of the reflector shape and proper feed tuning make it possible to achieve the desired antenna characteristics without replacing the parabolic mirror. Thus, the feasibility of efficient modernization of existing medium-class ground antennas through the integration of high-precision geometric reconstruction methods and electrodynamic modeling is confirmed.