Transformer-Based VCO for W-Band Automotive Radar Applications

A transformer-based voltage-controlled oscillator for a W-band frequency-modulated continuous-wave (FMCW) automotive radar application is presented. The design challenges imposed by the millimeter-wave frequency operation were faced through a circuit and layout co-design approach, supported by extensive electromagnetic simulations and accurate analysis of both the start-up condition and the tank quality factor. The oscillator was implemented in a 28-nm fully depleted silicon-on-insulator (SOI) complementary metal-oxide-semiconductor (CMOS) technology. It provided a 37 GHz oscillation frequency with a variation of around 4 GHz, thus achieving a tuning range of 11%. Moreover, a 77 GHz output signal was also delivered, which was extracted as a second harmonic from the input-pair common-mode node. The circuit exhibited low phase noises, whose average performances were -97 dBc/Hz and -121 dBc/Hz at 1 MHz and 10 MHz offset frequencies, respectively. It delivered a 77-GHz output power of -10.5 dBm and dissipated 26 mW with a 1 V power supply. The silicon area occupation was 300 x 135 mu m.

Automated summary

The transformer-based voltage-controlled oscillator, designed for an automotive radar application, operates at 37 GHz with a tuning range of 11% in a 28-nm fully depleted SOI CMOS technology. It delivers a 77 GHz output signal with low phase noises.