A 64QAM 94GHz CMOS transmitter SoC with digitally-assisted power amplifiers and thru-silicon waveguide power combiners

A 94GHz 64QAM 1Gbps reconfigurable system-on-chip (SoC) CMOS transmitter with digitally-assisted power amplifiers (DAPA) and back-etched thru silicon waveguide power combiners is presented. The SoC includes a 7M gate ASIC with reconfigurable digital modulation and transmit pre-coding. The ASIC feeds two 10b 1.4GHz current-steering DACs followed by a direct conversion IQ modulator driving eight DAPAs. A 64QAM signal achieves 3.9% EVM with 50dBc ACPR at 94GHz. The data rate is 1.05Gbps and the output power exceeds 10dBm. DC power is 2.1W. The SoC uses IBM 12SOI CMOS.