Multi-beam high gain steerable transmitarray lens for satellite communication and 5G mm-Wave systems

This paper presents the design of a high gain multi-beam transmitarray antenna. Designed antenna is capable of independently steering multiple beams in the azimuth and elevation plane by the two dimensional displacement of feed radiators placed in front of the passive meta-surface. The meta-surface acts as an electromagnetic lens. Unit cell of the meta-surface consists of three layers of Rogers 5880 substrate and four layers of etched copper. Unit cell is designed such that the phase of unit cell transmission coefficient is varied from 0 degrees to 360 degrees by changing length of the etched copper pattern. As a proof of concept, meta-surface is designed by using unifocal phase distribution. Multi-beam steering of 0 degrees to 360 degrees in azimuth plane and 0 degrees to 40 degrees in elevation plane has been achieved. Measured antenna peak gain is 34.2 dBi at 30 GHz. Later on, scan loss was optimized by synthesizing a meta-surface with bi-focal phase distribution. This is a mission enabling technology as the antenna supports seamless hand-off between satellites by forming multiple high gain independently steerable beams. Comparable antennas to the date are low gain, bulky, support limited number of beams, and have limited field of view. To the best of the author's knowledge, it is first time that high gain multi-beam antenna has been demonstrated by using a passive bi-focal meta-surface for continuous beam steering. Due to absence of active components the designed antenna is low cost and robust. Moreover, the substrate is selected such that the antenna can withstand harsh deep space environment and it can be folded for easy deployment. Due to potentially low fabrication cost and ability to support multiple beams, the proposed antenna is a good candidate for next generation satellite communication and mm-Wave 5G systems.