A 0.34-THz Wideband Wide-Angle 2-D Steering Phased Array in 0.13-$\mu$ m SiGe BiCMOS

Abstract

In this paper, a 0.34-THz $2\times 2$ phased array integrated circuit is presented, which demonstrates a new approach for implementing phased arrays in the millimeter-wave (mm-wave)/terahertz (THz) spectrum. The circuit structure consists of four unit standing wave oscillators. In each cell, fundamental frequency ( $f_{0}$ ) and odd harmonics are systematically cancelled, while the desired fourth harmonics ( $4f_{0}$ ) are combined and radiated by on-chip patch antennas. A phase-shifter-less mechanism is employed based on combining standing and traveling waves to create the required phase shift between the sources for beam steering. The transistors provide negative resistance to the circuit and generate the desired fourth harmonics through nonlinearity. Simultaneously, transistors are employed as active variable capacitors for varactor-less frequency tuning. The implemented phased array is capable of independent wideband frequency tuning and 2-D wide-angle beam steering. The circuit is fabricated in a 0.13- $\mu \text {m}$ SiGe BiCMOS process and is measured to have 52-GHz/15.1% frequency tuning range from 318 to 370 GHz and 128°/53° 2-D beam-steering angle. The chip consumes 310–640 mW power from a 1.5-V supply with −6.8-dBm maximum radiated power and minimum −93.1-dBc/Hz phase noise at 10-MHz offset. To the best of our knowledge, this paper has the largest bandwidth among fully integrated THz radiator/phased arrays as well as the widest angle beam steering among fully integrated THz phased arrays.