Low phase-noise balanced Colpitt InGaP-GaAs HBT VCOs with wide frequency tuning range and small VCO-gain variation

Paper in proceeding, 2007

Abstract—Low phase-noise InGaP-GaAs HBT VCOs, utilizing an on-chip ‘wide tuning range varactor’, have been designed, fabricated, and characterized. The primary design goals were low phase noise, wide continuous frequency tuning and small VCOgain variation. Two types of varactor were compared, a square varactor and a finger varactor. The square varactor achieves a frequency tuning of 27%, and the finger varactor 21%. The phase noise is typically -100dBc/Hz at 100kHz offset frequency. A VCO gain (sensitivity) of 160 MHz/V is obtained with a variation of less than 10%. The power consumption is controlled by the core dc-current and is of the order 50-100mW.