Design of a compact multilayer circularly polarized phased array transmit antenna system for satellite applications

An active phased array antenna which can scan its beam direction to a wide range of scan angles is presented in this paper. The paper proposes a new technique to compact a phased array antenna and making it suitable for applying in satellite payloads. This antenna should transmit high data rate signal from satellite to ground stations; and by spatial power combining the needed Effective Isotropic Radiated Power (EIRP) for the transmission link will be provided. The main beam can be scanned to 50° from normal. Polarization of the radiated wave of this antenna is circular. The designed antenna benefits from microstrip technology and has a unique low mass multilayer structure with two different substrates. For implementing antenna's RF circuits, Microwave Monolithic Integrated Circuits (MMICs) have been used and they are integrated expertly with microstrip radiators. Beam controller board sends necessary commands to MMICs for setting phase and amplitude of each array module. For decreasing side lobe level in high scan angles, genetic algorithm is applied and excitations of array elements are optimized. Design stages and simulation results of the array antenna are summarized in this paper and the results are compared with test results.