Low-phase-noise high-efficiency mimic VCO based on InGaP/GaAs HBT with the LC filter

This paper presents a fully integrated low-phase-noise and high-efficiency VCO based on InGaP/GaAs HBT, which shows excellent power-efficiency performance, for 802.11a application. For improved phase-noise performance, an LC filtering technique is adapted. The measured phase noise is -87.8 dBc/Hz at 100-kHz offset frequency and -111.4 dBc/Hz at 1-MHz offset frequency. The phase-noise characteristic is shown to improve by 5 dB after employing the LC filter. The figure of merit (FOM), defined as a function of the phase noise and power efficiency of the fabricated VCO with LC filter, is -172.1 dBc/Hz, which is the best result among the 5-GHz low-phase-noise VCOs. (C) 2004 Wiley Periodicals, Inc.