A 28 GHz RF-DAC With Analog LO Leakage Cancellation

A 28-GHz
$2\times 8$
bit quadrature RF-DAC is presented, which has an analog LO leakage cancellation circuit. It is based on a double-balanced Gilbert cell structure where current bleeding paths are introduced to prevent the cells from being completely turned off. LO leakages of the RF-DAC are canceled by controlling the current bleeding paths. It was fabricated in a 28-nm bulk CMOS process and achieved a −5.6-dBm CW output power with 12-mW power consumption from a 1.1 V supply and 3-Gb/s maximum data rate with 64-QAM signals. −45-dBc LO leakage was achieved using the proposed leakage cancellation technique.