A Multiband, Low Power and Low Phase Noise CMOS Voltage-Controlled Oscillator with NMOS Varactor for UWB Applications

A multiband low power and low phase noise LC-tank Voltage Controlled Oscillator (VCO) is designed for low band channels of the standard IEEE 802.15.4a. The LC-VCO uses the structure of complementary cross-coupled differential negative resistance and tank circuit, which contains varactor arrays for frequency fine-tuning and a spiral inductor. A method that uses resistor tail biasing for reducing the phase noise and the power consumption has been adopted. The circuit is fully designed in TSMC’s 180 nm technology process. The oscillator output provides three center frequencies of 3.5, 4, 4.5 GHz with good phase noises of -113.784, -116.703 and -126.753 dBc/MHZ at 1 MHz offset, while it dissipates 9mW power energy. The proposed LC VCO not only set a good balance between low phase noise and low power consumption, but it is also a highly desired circuit for multiband wireless transceiver systems, which are the major contributions of this proposed design