Abstract
This paper presents a low-power low-phase noise multiphase VCO that operates in 2.5 GHz and 5.0 GHz frequency bands. The dual-band multiphase VCO uses the frequency doubling method to generate the higher band signals from the lower band signals, and it shows excellent phase noise performance compared to other dual-band multiphase VCOs presented in literature. The VCO has been implemented in 0.18 mu m CMOS technology, and its frequency is tunable from 2.23 GHz to 2.68 GHz and from 4.46 GHz to 5.36 GHz. The measured phase difference between the I/Q signals is 90.0 degrees/88.9 degrees for the two frequency bands respectively. The phase noise figure-of-merits (FOMs) for the two frequency bands are -189.4 dB and -185.1 dB. (C) 2012 Elsevier Ltd. All rights reserved.