Performance evaluation of spherical reflectarrays for compact satellite antennas in Ka-band

Abstract This paper presents the design and evaluation of reflectarray antennas at spherical surfaces aimed at achieving an optimal compromise between electrical performance and mechanical deployability for satellite antenna solutions based on offset reflector configurations. By implementing printed reflectarray elements on a spherical surface, the phase-shifting elements mitigate spherical aberration, leading to enhanced focusing capabilities comparable to those of parabolic reflectors. The spherical geometry inherently simplifies the folding mechanism due to the rotational symmetry of the reflecting surface and minimizes the differential spatial phase delay, improving the reflectarray in-band performance. Simulation results demonstrate that large-aperture spherical reflectarrays can replicate the gain and beam quality of parabolic reflectors with smoother phase distributions than flat or multifaceted reflectarrays. The integration of spherical reflectarrays in dual-antenna configurations is evaluated to realize compact and efficient antenna systems for next-generation satellites.