Novel quadrature voltage controlled oscillator using series transistors coupling

Abstract

In this paper, a novel quadrature voltage controlled oscillator (QVCO) coupled by four transistors has been presented. The proposed QVCO consists of two identical LC negative resistance voltage controlled oscillators (VCO) and four series coupling transistors. Compared with the coupling method using paralleled transistors, the series transistors coupling method has lower power consumption and phase noise. The proposed QVCO is designed and simulated with Global Foundries 0.18 μm CMOS 1P6M RF process using Cadence IC Design Tools. The simulation results demonstrate that the proposed QVCO operates from 2.388 GHz to 3.376 GHz by adjusting the control voltage, and its phase noise is –140.6 dBc/Hz at 1 MHz offset. Moreover, the power consumption of the QVCO is only 1.84 mW with 1.25 V supply voltage.