The modeling of a horn antenna device operating in the 8–12 GHz frequency range, used in radar and satellite radio communication systems, was carried out, and its analysis and areas of application were studied. The investigated horn antenna operates in the microwave frequency range and has a simple construction that works effectively. Constructive models of the researched horn antenna in the H and E planes have been worked out, and mathematical modeling has been performed. It was revealed that planar patch antennas proved to be competitive for use in wireless telecommunication systems. The results of modeling the patch antenna showed that with the correct selection of the size and type of substrate, this antenna exhibits broadband properties and can be used in wireless 5G technologies. Aluminum was used as the antenna material . S-parameter analysis was performed to evaluate the compatibility of the antenna with the feed line and energy losses.