A triple-band SiGe HBT differential VCO using a reconfigurable multi-band resonator

A triple-band SiGe HBT differential VCO has been developed for the next generation multi-band and/or multi-mode wireless radios. It utilizes a reconfigurable multi-band resonator which is based on a dual-band resonator but can achieve a triple-band resonation by using a band-selective switch. The band-selective switch is comprised of a two-terminal SiGe HBT with base and collector short-circuited and can provide three different band-switching conditions for the multi-band resonator. The implemented 0.35-μm SiGe HBT differential VCO has achieved a low-band oscillation from 0.48 to 0.87 GHz, a middle-band oscillation from 1.75 to 1.92 GHz, and a high-band oscillation from 1.91 to 2.13 GHz. The phase noise at 100 kHz offset varies from -100 to -115dBc/Hz for all bands. This is the first report on the triple-band differential VCO using a dual-band resonator.