A K-band low phase noise transformer coupled Colpitts VCO in 0.18-µm CMOS technology

摘要

A K-band low phase noise Colpitts VCO was developed in 0.18-μm CMOS technology. The modified Colpitts VCO which uses a transformer to combine the main transistors and current switch transistors is proposed to improve the output voltage swing and the phase noise. The VCO achieves a good phase noise of -115 dBc/Hz at 1 MHz offset, and the chip size is 0.35 mm2.