Abstract: Design techniques for a low-power low-phase-noise CMOS LC direct bulk-coupled quadrature voltage-controlled oscillator (QVCO) was presented in TSMC 0.13 μm CMOS technology. A capacitor tapping technique was used to lower the phase noise and achieve load-independent frequency of oscillation. Class-C operation was used to further reduce the phase noise and power consumption. Quadrature coupling was achieved using bulk coupling, leading to reduction in both power and area. Postlayout simulations showed that the QVCO achieved a measured phase noise of －119.11 dBc/Hz at 1 MHz offset from the 6 GHz carrier frequency while consuming only 2 mW and occupies an area of 0.75 mm×0.45 mm.