This paper presents a low-power low-phase noise multiphase VCO that operates in 2.5GHz and 5.0GHz 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@mm CMOS technology, and its frequency is tunable from 2.23GHz to 2.68GHz and from 4.46GHz to 5.36GHz. The measured phase difference between the I/Q signals is 90.0^o/88.9^o for the two frequency bands respectively. The phase noise figure-of-merits (FOMs) for the two frequency bands are -189.4dB and -185.1dB.
['Juan Xie', 'M. Krishna Vamshi', 'Manh Anh Do', 'Chirn Chye Boon', 'Kiat Seng Yeo']
A low power low phase noise dual-band multiphase VCO