As the tuning frequency of an integrated LC-voltage controlled oscillator （LC-VCO） increases, it is difficult to co-design the active negative resistance core and the varactor to achieve wideband frequency range, lo...As the tuning frequency of an integrated LC-voltage controlled oscillator （LC-VCO） increases, it is difficult to co-design the active negative resistance core and the varactor to achieve wideband frequency range, low phase noise, constant bandwidth and small tuning gain together. The presented VCO solves the problem by designing a set of changeable varactor units. The whole VCO was implemented in a 0.18μm CMOS process. The measured result shows -120 dBc/Hz phase noise at 1 MHz offset. The measured tuning range is from 4.2 to 5 GHz and the tuning gain is 8-10 MHz/V. The VCO draws 4 mA from a 1.5 V supply voltage.展开更多
This paper presents a novel dual-band quadrature voltage controlled oscillator（VCO） with the gain proportional to the oscillation frequency.Frequency synthesizers with this VCO can reduce the bandwidth fluctuation o...This paper presents a novel dual-band quadrature voltage controlled oscillator（VCO） with the gain proportional to the oscillation frequency.Frequency synthesizers with this VCO can reduce the bandwidth fluctuation over all the frequency ranges without compensation or calibration.Besides the original switched capacitor array, an extra switched varactor array is adopted for the implementation of the proposed VCO.The tuning technique of changing the values of the capacitor and varactor at the same ratio is also derived.For verification purposes, a 2.5 G/3.5 G dual-band quadrature VCO is fabricated in a 0.13μm CMOS process for WiMAX applications. Measurement results show that the VCO gain is closely proportional to the oscillation frequency with±16%variation over the entire frequency range.The phase noise is -138.15 dBc/Hz at 10 MHz from the 2.5 GHz carrier and -137.44 dBc/Hz at 10 MHz from the 3.5 GHz carrier.展开更多
文摘As the tuning frequency of an integrated LC-voltage controlled oscillator （LC-VCO） increases, it is difficult to co-design the active negative resistance core and the varactor to achieve wideband frequency range, low phase noise, constant bandwidth and small tuning gain together. The presented VCO solves the problem by designing a set of changeable varactor units. The whole VCO was implemented in a 0.18μm CMOS process. The measured result shows -120 dBc/Hz phase noise at 1 MHz offset. The measured tuning range is from 4.2 to 5 GHz and the tuning gain is 8-10 MHz/V. The VCO draws 4 mA from a 1.5 V supply voltage.
基金supported by the National Natural Science Foundation of China(No.61106025)the National High Technology Research & Development Program of China(No.2012 AAO12301)
文摘This paper presents a novel dual-band quadrature voltage controlled oscillator（VCO） with the gain proportional to the oscillation frequency.Frequency synthesizers with this VCO can reduce the bandwidth fluctuation over all the frequency ranges without compensation or calibration.Besides the original switched capacitor array, an extra switched varactor array is adopted for the implementation of the proposed VCO.The tuning technique of changing the values of the capacitor and varactor at the same ratio is also derived.For verification purposes, a 2.5 G/3.5 G dual-band quadrature VCO is fabricated in a 0.13μm CMOS process for WiMAX applications. Measurement results show that the VCO gain is closely proportional to the oscillation frequency with±16%variation over the entire frequency range.The phase noise is -138.15 dBc/Hz at 10 MHz from the 2.5 GHz carrier and -137.44 dBc/Hz at 10 MHz from the 3.5 GHz carrier.
