A 20GHz LC-VCO for Satellite Microwave Communication Application

In this paper, a fully customized U-shape inductor is designed based on the UMC 40nm standard CMOS process. The customized inductor is placed in parallel with varactors to realize a LC resonating network. In the present voltage-controlled oscillator (VCO) circuit, a cross coupling NMOS transistor pair together with a PMOS current source are used to generate negative-resistance for supporting constant oscillating. The measurement results show that the oscillation frequency of the LC-VCO ranges from 17.034GHz to 20.207GHz under 0 to 1.2V tuning voltage. The measured phase noise at 1MHz offset frequency across the entire frequency tuning range is -95.53dBc/Hz ~ -98.64dBc/Hz. The whole circuit, including biasing circuit and buffer stages, consumes 31.6mW under 1.2V power supply.