77 GHz Radar Transmitter With PLL Based on a Sub-Harmonic Gilbert Frequency Doubler

This contribution highlights the usage of a high-quality voltage controlled oscillator (VCO) at 19.25 GHz fundamental frequency with a succeeding times four frequency multiplication scheme facilitating a 77 GHz output frequency. Signal tapping at the VCO's common emitter node allows obtaining the second-order harmonic tone that drives a single Gilbert frequency doubler. Beneficial to the PLL implementation is a reduced overall prescaler ratio allowing faster frequency ramps.