A low phase noise 19 GHz-band VCO using two different frequency resonators

A low phase noise 19 GHz-band VCO is presented in this paper. The VCO has a novel tuning circuit consisting of two resonators which have a different resonant frequency. With these two resonators, the Q factor of the tuning circuit of the VCO is improved, and low phase noise can be achieved. The measurement results of the developed VCO show phase noise from -120 dBc/Hz to -122 dBc/Hz at 1 MHz from the carrier over a 290 MHz tuning bandwidth in the 19 GHz-band. This VCO achieves one of the lowest recorded values of phase noise at K-band.