A 4-port inductor based compact dual-core VCO with improved phase noise performance

Utilizing the concept of impedance scaling, dual-core LC-VCO helps to meet stringent phase noise requirement at the cost of higher power and higher area. A 4-port inductor with dual tap is proposed for dual-core LC-VCO architecture which reduces power consumption for the given phase noise performance or improves phase noise performance for given power consumption. 4-port inductor has lesser effect of current crowding and hence it has better quality factor which leads to improvement in phase noise performance. Significant area reduction is also obtained due to single 4-port inductor as against two 2-port inductors with higher separation to avoid mutual coupling in traditional dual core LC-VCO. Traditional dual-core VCO and 4-port inductor based dual-core VCO have been implemented in 130 nm BiCMOS technology to compare the phase noise performance. 4-port based dual core VCO demonstrates phase noise improvement of 3 dB at 1 MHz offset when running at 21.4 GHz.