A study of flicker noise suppression of K-band VCO using striped inductor

Flicker noise suppression of K-Band scaled-CMOS VCO using striped inductors have been studied. The phase noise degradation is a problem of high-frequency VCO. Especially phase noise which arise from flicker noise is the most significantly in the case of using noisy scaled CMOS process. In this work, we present flicker noise contribution phase noise improvement using striped inductors. Striped inductors have been studied for thermal noise contribution phase noise improvement due to skin effect suppression, however, they are also effective to suppress flicker noise contribution phase noise improvement since 2nd harmonic reduction by its higher parasitic capacitance. The experimental results show VCO´s corner frequencies between thermal noise contribution region and flicker noise contribution region were 25 and 55% reduction using striped inductor with 2 and 4 μm metal space, respectively. A 1-MHz-offset phase noise show -104, and -103 dBc/Hz using 2 and 4 μm metal space striped inductor, respectively. It exhibits approximately 5 dB better phase noise than conventional inductor VCO. The process technology using all experiments were 65-nm standard CMOS with thick Cu metal.