A 20-32GHz Digital Quadrature Transmitter with Notched-Matching and Mode-Switch Topology for 5G Wireless and Backhaul

In this paper, a mm-wave wideband digital quadrature transmitter with improved efficiency for the 5G wireless and backhaul communication is presented. A novel synthesized notched-matching network is proposed to decrease the impedance mismatch from the interconnection of power digital-to-analog converter (power-DAC) cells operating at mm-wave bands. The performance is further optimized at the low- and high-bands by mode-switch of the quadrature signal generator, interstage matching of sign map, and power-DAC output-matching, simultaneously. Based on the mechanisms mentioned above, a 2×10-bit digital quadrature transmitter operating at 20-32GHz is implemented and fabricated using a conventional 28-nm CMOS technology, which exhibits the saturated output power of 19.02dBm, 34.4% maximum drain efficiency, and maximum system efficiency of 22.1%, respectively. Such mm-wave transmitter can support 64QAM modulation signals with 3Gb/s data-rate, -28.9dB EVM, 9.96dBm output power, and -33.6dBc ACPR.