Low-Phase Noise QVCO for WLAN in 0.13-μm RF CMOS Process Technology

In this paper, a Quadrature Voltage Controlled Oscillator of a wireless transceiver operating in the 5GHz UNII band of the wireless LAN 802.11a standard was proposed. In addition, a new structure of low-noise, low-power Quadrature Coupled VCO was proposed using the quadrature phase output as an input to the switching current source. If this structure is applied to other circuits such as a structure in which the current source is separated or a common use of a current source, a phase noise characteristic of 17 dB better than the existing VCO can be obtained. In particular, it is designed to operate with low power in a simple structure compared to the existing in-phase QVCO. The circuit was designed to operate with a supply voltage of 1.2V by the TSMC 0.13μm RF CMOS process. The measured VCO has a large tuning range of 20% operating at frequencies of 4.5 - 5.6 GHz, and phase noise of -117 dBc/Hz or less was obtained at the 1 MHz offset. The output phase error of the proposed QVCO was less than 0.5 degrees, and the total power consumption was able to obtain 5.3 mW at 1.2V.