Contents I. Introduction
Space antennas are often required to provide high-gain while preserving a low profile and presenting low losses. Moreover, on-orbit beam-steering is also desirable for directed beam data transfer from the satellite to the ground stations. Classical solutions for beam steering high-gain antennas in-clude reflectors mounted on rotating platforms [1] and phased arrays [2], but their size, weight and power consumption may not fit the conditions for new generation of satellite constellations and small satellites [3]. Other solutions consist in modulated metasurface (MTS) antennas [4]–[6] or compact beam-formers combined with slot arrays [7] which have been used to obtain multiple beams and can achieve scanning by beam switching. Although the later solutions fulfill the high-directivity and low-profile requirements, the azimuthal scanning range is limited. An interesting approach to obtain continuous beam-scanning consists in using in-plane mechan-ical rotation with planar structures, such as Risley prisms [8] or variable inclination continuous transverse stubs (VICTSs) [9]. The former is bulkier due to the stack of the two prisms, whereas the later presents a lower profile. Nonetheless, the in-plane rotation still entails a non-negligible complexity.
