Design of 24GHz CMOS VCO using armstrong topology with asymmetric transformer

The design and characterization of a 24-GHz 0.18µm CMOS voltage-controlled oscillator are presented. By utilizing the asymmetric-width transformer and the forward-body bias (FBB) techniques, the proposed VCO can be operated at reduced supply voltage and power consumption while maintaining the circuit performance in terms of phase noise and signal output swing. With these techniques, the transistor size can be reduced to reach a higher oscillation frequency under low power budget. Consuming a dc current of 8mA with the supply voltage of only 0.6V, the K-band VCO exhibits a frequency tuning range of 840MHz, a phase noise of −104.6dBc/Hz (1MHz offset), and a figure of merit up to 185dBc/Hz.