Ultra-Thin Low-Cost Electronically-Beam-Scanning Reflectarray for Ka-Band Satellite Communications on the Move and 6G

This invited paper reports our recent progress in the research on low-profile light-weight low-cost Ka-band electronically beam-scanning array antennas using printed reflectarray antennas. The traditional reflectarray antenna has a bulky size, as it is illuminated by a feed (such as a horn) and the thickness is proportional to the aperture size of reflectarray. To significantly reduce the thickness of reflectarrays, a leaky-wave feed is employed to illuminate the reflectarray while achieving high efficiency. The thickness of reflectarray antenna proposed here is < 3% of that of the traditional front-fed reflectarray with the same aperture size. Printed unit cell with two-bit phase resolution is employed to achieve electronically beam scanning of reflectarrays. This enables a significant reduction of the cost of antenna, compared to traditional phased arrays using a very large number of Ka-band phase shifters and RF front ends. The design and experimental results of the Ka-band beam-scanning refectarray antennas are presented and discussed. The Ka-band beam-scanning refectarray is shown to achieve an aperture efficiency of 35.1%. The results demonstrate that this antenna is promising for applications into Ka band satellite communications on the move and the 6G.