A 23.67-to-45-GHz wide tuning range dual VCO with phase noise enhancement in 90-nm CMOS technology

A 23.67-to-45-GHz voltage-controlled oscillator (VCO) using standard 90-nm CMOS technology is presented in this paper. A dual VCO with switchable inductor and varactor arrays is proposed and successfully implemented in the LC-VCO design. The proposed switchable inductor changes the inductance in-directly on radio frequency (RF) signal path, and brings minimum loading effect on the quality factor of the resonator. The VCO centered at 34.4 GHz achieves a wide tuning range of 62.1%. The measured phase noise is -100.8 dBc/Hz at 1 MHz offset from the carrier frequency of 23.67 GHz. The VCO has a core chip size of 0.35 × 0.65 mm² and consumes 16-20mW from a 1.2 V supply voltage. To the best of our knowledge, the proposed VCO has the highest FOM_T of -194.3 among all reported above 10-GHz VCOs.