A 0.28 THz Power-Generation and Beam-Steering Array in CMOS Based on Distributed

Abstract

In this paper, we present a scalable tran smitter archi- tecture for power generation and beam-steering at THz frequen- cies using a centralized frequency r eference, sub-harmonic signal distribution, and local phase control. Th e power generation and radiator core is based on a novel method called distributed active radiation, which enables high conversion ef ficiency from DC to ra- diated terahertz power above f of a technology. The design evo- lution of the distributed active radiator (DAR) follows from an in- verse design approach, where metal surface currents at different harmonics are formulated in the s ilicon chip for the desired elec- tromagnetic field profiles. Circuits and passives are then designed conjointly to synthesize and control the surface currents. The DAR consists of a self-oscillatin g active electromagnetic structure, com- prising of two loops which sustai n out-of-phase currents at the fundamental frequency and in-phase currents at the second har- monic. The fundamental sign al, thus gets, spatially filtered, while the second harmonic is radiated sel ectively, thereby consolidating signal generation, frequency mult iplication, radiation of desired harmonic and filtration of undesired harmonics simultaneously in a small silicon footprint. A two-d imensional 4x4 radiating array implemented in 45 nm SOI CMOS (without high-resistivity sub- strate) radiates with an EIRP of +9.4 dBm at 0.28 THz and beam- steers in 2D over 80 in both azimuth and elevation. The chi