A Fully Integrated QPSK/16-QAM <i>D</i>-Band CMOS Transceiver With Mixed-Signal Baseband Circuitry Realizing Digital Interfaces

This work presents a fully integrated D-band transceiver (TRX) in 28-nm CMOS. The system architecture introduces a radio-frequency digital-to-analog converter (RF-DAC) and the complete mixed-signal baseband (BB) circuitry, including the equalizer, realizing fully digital BB interfaces at 24-Gb/s quadrature phase shift keying (QPSK) and 48-Gb/s 16-quadrature amplitude modulation (16-QAM). Innovations at the circuit level encompass: 1) the D-band RF front end (FE) using the proposed hybrid matching technique; 2) the two-stage conversion paths highlighting the Cartesian RF-DAC with an embedded four-tap finite impulse response (FIR) filter; 3) the local oscillator (LO) including an all-digital phase-locked loop (ADPLL) and the LO distribution network; and 4) the mixed-signal BB circuitry. The TRX achieves a transmitter (TX) bandwidth of 21 GHz, a receiver (RX) bandwidth of 18 GHz, a TX saturated output power (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$P_{\text {sat}}$ </tex-math></inline-formula>) of 13.1 dBm, a TX output 1-dB compression point (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text {OP}_{\text {1 dB}}$ </tex-math></inline-formula>) of 7.5 dBm, and an RX noise figure (NF) of 9.3 dB.