Design and optimization of CMOS radio frequency LC-tank voltage-controlled oscillator

Abstract

In this thesis, a novel LC-tank Voltage-Controlled Oscillator (VCO) structure for wireless applications is presented. It was simulated by Agilent Advanced Design System (ADS) and fabricated in Charted Semiconductor Manufacturer (CSM) 0.35A?m standard CMOS process. The proposed structure operating at 2.4GHz for Bluetooth applications reduces the worst-case frequency pushing to 0.55%/V, and increases the frequency tuning capability to about 23%. Although the phase stability factor of the LC-tank is only about 2.5 in this case, the Figure Of Merit for oscillators (FOM) reaches about -180dBc/Hz after optimization. The proposed structure and the FOM optimization method are applicable to VCO circuits operating at higher frequencies, such as 5GHz VCO for Wireless Local Area Network (WLAN) applications.