Compact Sub-THz Frequency Conversion Module in 28-nm CMOS for D-Band Radar Transceiver

This paper proposes a compact sub-THz frequency conversion module for D-band transceivers, fabricated using a 28-nm CMOS process. The module integrates an injection-locked frequency multiplier (ILFM) for Tx signal frequency up-conversion and an active Gilbert double-balanced mixer for Rx signal frequency down-conversion. The system was tested on a probe station. Utilizing a tunable coupling-coil technique and optimized inductance, the ILFM achieves a locking range of 105.2-125.5 GHz with an output power of -4.5 dBm. The Gilbert mixer demonstrates a conversion loss of -6.5 dB across the same range with an LO power of -4.2 dBm. The active region of ILFM and mixer chips occupy areas of 0.31 mm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> and 0.51 mm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup>, respectively.