Spatial Multi-Feed Beam Steering Reflectarray Payload for Smallsats with Adapted Field of View

Abstract

This work presents a spatial multi-feed beam steering reflectarray concept intended for compact small satellite payloads with adapted field of view (FoV) coverage. Unlike conventional reflectarray beam steering approaches based on tunable unit cells or mechanical reconfiguration, the proposed approach exploits the controlled displacement of the phase center of a digital planar feed array to illuminate a passive reflectarray surface from different spatial positions, enabling beam steering without tunable unit cells or mechanical reconfiguration. First, the beam steering mechanism is analyzed through the phase gradients induced by feed displacement, including the impact of amplitude illumination and incidence angle-dependent unit cell response. Then, the concept is experimentally validated at 30 GHz using a developed reflectarray and a 2 × 2 patch array feed repositioned over a multi-position interface to emulate overlapping subarrays of a virtual 4 × 4 feed array. The measured radiation patterns show good agreement with simulations, confirming the predicted beam pointing trends with measured gains between 26.57 and 27.91 dBi for the evaluated subgroups. Finally, a mission-oriented architecture for the UPMSat-4 scenario is analyzed, considering a reflectarray surface up to 600 mm × 400 mm integrated into solar panels and a 16-element linear array feed. The results demonstrate the feasibility of generating a linear multibeam FoV, achieving beam overlap and a minimum carrier-to-noise ratio (C/N) of approximately 32 dB in the considered link budget scenario. The proposed architecture provides a scalable and low-complexity alternative for flexible smallsat antenna payloads.