A low phase noise and low power series coupled quadrature VCO for dual band application

Abstract

To design a multi standard and a multi band transceiver, a quadrature voltage controlled oscillator (VCO), which has a wide tuning range, is an essential building block, while providing low phase noise with low current consumption. In this thesis, a dual band quadrature VCO in $0.18\microm$ CMOS process is presented with simulation and experimental results; and its error analysis. To accomplish dual band operation, reconfigurable LC tank is adopted. Series coupling transistors are attached to generate quadrature phase signal with low phase noise and low power consumption. To improve phase noise performance, a filter inductor at the common source node is added to block draining second harmonic current to ground. The measured phase noises of low frequency mode and high frequency mode are -123.8 dBc/Hz and -115.06 dBc/Hz at 1 MHz offset frequency and figure of merit (FoM) of -181.8 dB and -180.5 dB with 4 mA current consumption with a 1.7 V supply.