Dual-band quadrature voltage-controlled oscillator using differential inner-diamond-structure switchable inductor

A dual-band quadrature voltage-controlled oscillator (QVCO) with high figure-of-merits (FOMs) and cost-area efficiency is presented by integrating with differential inner-diamond-structure switchable inductors which have improved performances. This proposed QVCO is fabricated in a 0.18-μm complementary metal-oxide semiconductor process with an active-region area of 0.61 mm2. The QVCO core totally consumes 6.8 mA from 1.8 V supply voltage. The frequency tuning ranges are 120 MHz (from 3.18 to 3.3 GHz) for the low-band and 500 MHz (from 6.94 to 7.44 GHz) for the high-band, while the tuning voltage rises from 0 to 1.8 V. The best phase noises with an offset frequency of 1 MHz from the oscillation frequency in the low- and high-bands are −121.9 and −117.5 dBc/Hz, respectively. The measured phase errors in both high-band and low-band are less than 1°. The calculated FOMs, no matter the switch is off or on, are better than −180 dBc/Hz.