A low-power wideband LC VCO has been designed and implemented in a 90-nm CMOS technology. Wide tuning range, low phase noise and low power consumption are achieved thanks to the adopted LC tank, which makes use of shunt-connected switched-coupled inductors and a proper arrangement of varactors. The shunt-connected switched-coupled inductors provide coarse tuning and phase noise optimization without using amplitude calibration loop or trimming of the bias current. The proposed varactors configuration employs accumulation mode thin and thick MOS devices, which has been differently biased to obtain tuning range maximization along with minimization of the amplitude-to-phase noise conversion. The LC-tank topology and inductor layout have been properly designed to attain a die area comparable to a single-inductor VCO, taking advantage of the inductors mutual coupling. The VCO exhibits a phase noise at 1-MHz offset frequency lower than over the entire tuning range and achieves at 1.2 GHz. It provides a tuning range of 51% from 1.13 GHz to 1.9 GHz with a tuning voltage ranging from 0 to 1.2 V. Despite a very low current consumption, which is 0.88 mA from a 1.2-V supply, the proposed VCO has the outstanding PFTN figure-of-merit of 10. The VCO core die area is 0.5 .Index Terms-CMOS voltage controlled oscillators, low-power circuits, phase noise, switched inductors, tuning range, wireless sensor networks.

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A monolithic 5-GHz down-converter, which consists of a two-stage low noise amplifier (LNA) and a double-balanced mixer, was designed using a 46-GHz-fT silicon bipolar process. The proposed down-converter exhibits a power gain as high as 21 dB, a 4.7-dB SSB noise figure and an input compression point of -21 dBm. Moreover, an on-chip image rejection ratio (IRR) higher than 70 dB is achieved by making use of passive LC notch filters. The circuit was assembled in a 5x5 mm2 low-cost QFN 24-lead plastic package and draws only 23 mA from a 3-V power supply.