A 5–20GHz tunable LC-VCO using variable bridge inductor

An ultra-wide frequency range tunable LC-VCO is developed using a novel multi-stage variable inductor, which has a bridge architecture and a miniature 3D solenoid structure. Because of the inductor, the continuous tuning range over 15GHz (5~20GHz) is achieved with 10.6mW total power consumption. Phase noise at 1MHz offset is -103dBc/Hz @10GHz and -87dBc/Hz @20GHz. The chip area is smaller than 1/10 of wide range LC-VCOs reported.