Phase noise analysis of a tail-current shaping technique employed on a BiCMOS voltage controlled oscillator

A BiCMOS Silicon Germanium cross-coupled differential-pair narrowband voltage controlled oscillator with a tail-current shaping technique to improve phase noise performance is implemented and experimental results are presented. Several VCOs are fabricated on-chip to serve for a practical comparison and the results are also compared to simulated results. Simulation results provided a 3.3 dBc/Hz improvement from −105.3 dBc/Hz to −108.6 dBc/Hz at a 1 MHz offset frequency from the 5 GHz carrier. Measured results confirm the correlation of phase noise performance between simulation and prototype. Acceptable phase noise performance compared to previous works is achieved using a relatively cost-effective technology.