The parabolic-torus-phase reflectarray antenna

Since the early 1990´s, printed reflectarrays antennas have emerged as the new generation of high-gain antennas, providing many advantageous features such as low-mass, low-profile, and low-cost over reflectors and printed arrays. Moreover, they are also quite suitable for applications requiring high-gain and beamscanning features. For the beam-scanning operation, one approach is to equip the reflectarray elements with a phase tuning mechanism. Another approach is to move the phase center of the feed antenna, which ultimately changes the phase on the reflectarray aperture, leading to a scanned beam. While each approach has its own advantages, the primary advantage of the later approach is the relatively low cost. The drawback however is that it suffers from poor collimating properties for scanned beams in conventional parabolic-phase reflectarrays.