High Performance VCO Design Using High Q SIW Resonator

This paper presents a novel methodology to implement LC tank in the design of a Voltage Controlled Oscillator (VCO) for improved phase noise and tuning range. For frequency selection, Substrate Integrated Waveguide (SIW) based LC resonator is proposed and employed in cross-coupled differential pair. The SIW is designed to operate in the range from 55 GHz to 70 GHz while the VCO is designed to work at 60 GHz using 65 nm CMOS technology. The SIW resonator based VCO achieves high Quality factor (Q), improved tuning range and phase noise compared to conventional LC tank VCO. Simulation and analysis of results are performed in Keysight Advanced Design Systems while SIW structure is designed in Ansys HFSS which forms the feedback path. A detailed comparison is made between the two methods. The conventional LC VCO has a measured tuning range of 7.5 GHz while consuming 2.38 mW power from a 1-V power supply where as SIW tank VCO has an improved 15 GHz tuning range, absorbing 0.385 mW power from a 1-V power supply. The LC VCO and SIW tank VCO has a phase noise of -143.585 dBc/Hz and -113.8 dBc/Hz at 1 MHz offset and corresponding figure of merits are - 164 dBc/Hz and -195 dBc/Hz respectively.