An X-band CMOS quadrature balanced VCO

A new quadrature balanced voltage controlled oscillator (B-VCO) is presented. The quadrature and single B-VCO with identical components are implemented in 0.18 /spl mu/m CMOS technology. The quadrature B-VCO has lower phase noise, higher oscillation frequency and higher figure of merit (FOM) than the single B-VCO. The measured phase noise values of the single and quadrature VCO are -114.83 and -116.67 dBc/Hz at the offset frequencies of 1 MHz at the center frequency of 10.21 and 10.81 GHz, respectively. Both VCO cores consume about 8.8 mA from a 1.8 V supply. The FOM of 183 and 185 dB are achieved in the quadrature and single VCO respectively.