Reconfigurable Transmitarrays at Ka-Band with Beam-Forming and Polarization Agility

Abstract

This paper presents transmitarray-based antenna solutions for SATCOM transmit (Tx) user terminals at Ka-band. We propose a new electronically-reconfigurable unit-cell structure which combines a 2-bit phase control with circular polarization agility. Six p-i-n diodes are integrated into the proposed unit-cell implemented by stacking two halfwavelength periodic structures: a reconfigurable phase-shift module and a switchable linear-to-circular polarization converter. The two structures, developed on a standard PCB stack-up, are separated by an optimized air gap. A 576-element square transmitarray with 3456 integrated p-i-n diodes has been designed, optimized, and fabricated. To enhance the advantages of this innovative architecture, its performance is compared to the one of our previous transmitarray demonstration based on a random sequential combination of 576 vertically-and horizontally-polarized 2-bit reconfigurable unit-cells. To the best of our knowledge, this represents the first demonstration of transmitarray with two stacked reconfigurable functionalities.