A 47-to-100GHz Oscillator-Embedded Artificial Transmission Line Based LO Generator Achieving Averaged FoMt of -193.7dBc/Hz

This paper presents an octave-bandwidth millimeter-wave local oscillator (LO) generator architecture covering a frequency range from 47 to 100 GHz. The proposed LO generator comprises six oscillator-embedded artificial transmission line (OATL) unit cells. Each OATL cell is designed to oscillate within a designated frequency sub-band when activated; collectively, the six oscillators provide continuous frequency coverage across the entire 47–100 GHz range. When an OATL unit cell is deactivated, it contributes only a parasitic capacitance to the main signal path, which is naturally absorbed into the periodic transmission-line structure without degrading the overall operation. Each oscillator employs a gm-boosted cascode Colpitts topology to enhance start-up and improve load-driving capability. And an inductor-based tuning technique is adopted to replace the conventional capacitor-based tuning approach. The chip is fabricated in a 65-nm CMOS process and achieves a continuous frequency tuning range from 47 to 100 GHz, corresponding to a 72.1% tuning range. The measured DC power consumption varies from 9.6 to 27.6 mW across the tuning range, providing -6.5dBm to -2dBm output power at a single output. The measured phase noise at a 10 MHz offset for the six sub-band VCOs is -116, -114, -118, -117, -114, and -112 dBc/Hz, respectively. This work achieves an averaged FoMt of -193.7 dBc/Hz and the best case FoMt of -199.8 dBc/Hz.