A Low Phase noise LC VCO for Single Chip UHF RFID Reader

A low phase noise VCO(voltage controlled oscillator)for single chip UHF RFID Reader is proposed.The regulator and filtering technology are adopted in order to suppress the noise from VDD and shot the second harmonic of current source for phase noise reduction in 1/f3 region.Meanwhile,proper L with a relative better Q value is chosen to improve phase noise in 1/f2 region.Low noise bandgap is also added in the propose VCO.The VCO is implemented using UMC0.18 μm MM/RF CMOS technology.Compared with the traditional VCO,simulation result shows the phase noise reduction is around 5 dB in all frequency regions.The center frequency of proposed VCO is 1.8 GHz with the tuning rage of 11% while the power consumption is 7.2 mA at 3.3 V.The VCO has phase noise of-127 dBc/Hz@1 MHz.