A Compact 25-32 GHz High IMRR Double Quadrature CMOS Transmitter for 5G Applications

This paper presents a wideband calibration-free compact mmWave transmitter (TX) with a high image rejection ratio (IMRR) for 5G applications. A novel architecture has been proposed using a double quadrature (DQ) direct upconversion modulator. The proposed TX architecture uses a 3-stacked differential power amplifier (PA) stage to increase P
sat
. New layout techniques have been proposed for the symmetric routing of quadrature LO signals. The TX designed in 40 nm CMOS process operates from 25-32 GHz. Post-layout EM simulations show 20 dBm of P
sat
at 28 GHz with 46.4 dB of IMRR. IMRR has been obtained ≥40 dB across the output bandwidth. The error vector magnitude (EVM) is better than -31 dB for a 256 QAM OFDM signal with 400 MHz signal bandwidth with an average output power of 9 dBm. An area-efficient implementation of mmWave TX delivering 20 dBm P
sat
is presented. The design also supports a wide IF bandwidth from 200 MHz to 1.5 GHz.