K-and C-Band Low Phase Noise MMIC VCOs Using a Linear Varactor

Abstract

A new circuit configuration is proposed for low phase noise VCOs. A linear varactor consisting of an FET varistor and an MIM capacitor eliminates 1/f noise up-conversion of the frequency tuning element. The measured results of the fabricated 20 GHz-and 6 GHz-band MMIC VCOs indicate more than 10 dB phase noise improvement compared with conventional varactor diode-based MMIC VCOs.