Application of bifocal concept to dual reflectarray configurations for multi-beam satellite antennas in Ka-band

Abstract

Abstract-This contribution describes the design of a multibeam dual reflectarray antenna for operation in transmission in . The bifocal design concept has been used to obtain an improved performance for the off-axis beams with respect to the single focused antenna. The required phase-shift distributions are initially obtained with the reflectarrays in parallel planes, and then adjusted to compensate the tilting of both reflectarrays in the final Cassegrain configuration. The simulated radiation patterns in the elevation and azimuth orthogonal planes have been calculated for the two beams generated by the focuses, and then the multi-beam performance of the antenna has been evaluated.Index Terms-dual reflectarray, multi-beam antenna, bifocal design, satellite communications, Ka-band.

Preliminary simulations of flat and parabolic reflectarray antennas to generate a multi‐spot coverage from a geostationary satellite

“…The measured levels of cross‐polarisation in the main lobes are about 26 dB below the co‐polar component. Similar and larger values of cross‐polar discrimination are obtained in other reflectarray prototypes also designed with cells based on coupled parallel dipoles [24, 25].…”

“…Thus, the cross‐polarisation is mainly produced by the offset antenna configuration and the reflectarray elements. Note that previous offset reflectarray prototypes have shown measured cross‐polar discriminations larger than 25 dB, as in [22, 24, 25].…”

Study of bifocal dual reflectarray configurations for multi-beam antennas in ka-band

“…If the initial conditions of the bifocal synthesis exhibit axial symmetry (see Fig. 1(a)), the two phase curves can be rotated around the symmetry axis to obtain a surface phase distribution for each reflectarray, producing a focal ring that contains Fi and F2 [5].…”

Low‐costlens antenna for5Gmulti‐beam communication

“…Nevertheless, phased arrays provide only one beam and the required electronics for beam steering increase the antenna complexity, losses and cost. Other solutions increase the spectral efficiency by including more than one input port in the antenna, as in designs using a Rotman lens, 7 a Butler matrix, 8 reflectarrays 9 or cylindrical lenses 10 . In these approaches, each port generates a beam pointed to different directions, and theoretically several communication channels could be established simultaneously.…”