A 1V 4 GHz-and-10 GHz transformer-based dual-band quadrature VCO in 0.18 μm CMOS

A notch-peak cancellation concept is introduced in transformer-based LC tanks to achieve a dual-band quadrature VCO. Fabricated in 0.18 μm CMOS process and operated at 1V supply, the QVCO prototype measures a stable dual-band operation from 3.27 GHz to 5.02 GHz and from 9.48 GHz to 11.36 GHz. At 4.2 GHz and 10 GHz, the QVCO measures phase noise at 1 MHz offset of -116.3 dBc/Hz and -112 dBc/Hz, and sideband rejection ratios (SBR) of 49 dB and 47 dB while drawing 6 mA and 10 mA, respectively. The QVCO occupies an active area of 0.88 mm².