A 230-GHz Wideband High-Efficiency Beam-Steering 1×2 Phased-Array Transmitter in 40-nm CMOS

This work presents a 230-GHz 1×2 phased-array transmitter (TX) that integrates a voltage-controlled oscillator, two 360° phase-shifting amplifier–frequency–multiplier chains (AMCs), and two high-resistivity Si dielectric resonator antennas (DRAs). Each AMC comprises a driver amplifier (DA) and a frequency tripler (FT). The DA employs a phase-shifter-embedded impedance-matching network that simultaneously provides balun functionality, >120° phase shifting, and impedance transformation, effectively reducing power loss and chip area. The FT employs a fundamental voltage-tuning technique to tolerate higher input power without voltage breakdown issues, improving the output power by 2.5 dB. The DRA utilizes a tapered feeding structure to broaden the bandwidth, achieving an antenna gain of 3.9 dBi and a fractional bandwidth of ~10% at 230 GHz. Fabricated in a 40-nm CMOS process, the proposed TX provides frequency tuning from 215 to 240 GHz, an equivalent isotropically radiated power of 8.5 dBm, and a 60° beam-steering range at 225 GHz.