Design of a 120 GHz Reflectarray with Printed Feed

High gain antennas play a crucial role in radar and telecommunications. The Reflectarray antenna (RA) is good candidate, especially in the millimeter wave frequency band (30 GHz to 300 GHz) because of their ability to produce focused and controllable beams. However, the need to mechanically adjust the distance between the RA and the primary feed in order to meet focal length requirements, is a disadvantage that we try to overcome in this paper. The key novelty of the proposed configuration lies in the fact that the primary feed and the RA share the same substrate. To meet these requirements, a miniarray of printed patches is designed to generate a deflected beam and a PEC sub-reflector is used to redirect the beam toward the reflectarray. We evaluate the performance through full-wave simulations at the design frequency of 120 GHz. While the primary feed performs as expected, discrepancies in the simulation of the entire structure highlight the need for design adjustments, particularly with regard to phase compensation, element configuration and a thorough analysis of the influence of the mirror. Despite the challenges, the methodology demonstrated significant computational efficiency and identified key areas for improvement, paving the way for further refinement of the system.