A Wide Tuning Range Low Phase Noise Voltage Controlled Oscillator

In this paper, a wideband Voltage-Controlled Oscillator (VCO) is presented that operates in 2.38GHz to 3.9GHz, representing 48.6% tuning range. This circuit has been aimed to the wireless and WiMAX networks. The proposed circuit has low KVCO (frequency variation per 1V) and hence, reduced spur, when used in a Phase Locked Loop (PLL). This work also proposes a new method for optimization of capacitors values and transistors size in the capacitor bank. Phase noise of the proposed circuit is -120.8 dBc/Hz at 3.9GHz center frequency, at 1MHz offset. The supply voltage is 1V and the power consumption is 4.1mW. The proposed circuit has been laid out using TSMC 0.18 um RF CMOS foundry design kit in CADENCE. The post-layout simulation results prove excellent performance of the proposed circuit.