A Chip-Integrated 240-GHz-Reflectarray with Antennas on Glass Superstrate

In this article, a chip-based reflectarray for operation at 240 GHz is presented, where the unit cell is designed in compatibility with standard chip technology to allow integration of a switchable element in a subsequent design iteration. Different reflection phase states are obtained by connecting a transmission line of variable length to an on-chip patch, which in turn is coupled to a radiating patch antenna on a glass superstrate. To verify the design, a large array synthesized from three discrete phase states is investigated in full-wave simulations for different beam steering scenarios. As a proof-of-concept, a back-end-of-line chip with a fixed phase progression is fabricated and assembled. Experimental characterization of its far-field radiation pattern successfully demonstrates beam steering by 41°.