Analysis and Design of Wide-Band Millimeter-Wave Transformer-Based VCO and ILFDs

Several transformer-based techniques are proposed to enhance the frequency tuning range of mm-wave voltage-controlled oscillators (VCOs) and the frequency locking range of injection-locked frequency dividers (ILFDs). Firstly, a switched-transformer VCO (ST-VCO) based on dual-band topology is proposed to increase the frequency tuning range. Secondly, transformer-distribution ILFDs (TD-ILFDs) are demonstrated to achieve much improved frequency locking range with compact chip area and low power consumption. Thirdly, the injection-saturation problem of ILFDs is identified, analyzed, and solved in this work. A VCO and three different TD-ILFDs are designed and fabricated in a 65 nm CMOS process. The proposed ST-VCO measures wide tuning range of 22.3% from 62.1 GHz to 78.3 GHz with phase noise of -112 dBc/Hz at 10 MHz offset while consuming 7.7 mW, corresponding to FoM and FoMT of -180.4 dBc/Hz and -187.4 dBc/Hz, respectively. The proposed 60-GHz TD-ILFDs measure locking range of 19.6 GHz (29.6%), 19.8 GHz (29.2%), and 3.8 GHz (6.1%) while consuming 1.44 mW, 1.44 mW, and 0.44 mW.