A 20-GHz InP-HBT voltage-controlled oscillator with wide frequency tuning range

This paper presents the design and implementation of a 20-GHz-band differen tial voltage-controlled oscillator (VCO) using InP heterojunction-bipolar-t ransistor process technology. Aimed at 20- or 40-Gb/s fiber-optic applicati ons, the design is based on a single-stage feedback amplifier with no inten tional L or C. The salient features of the proposed VCO are wide frequency tuning range compared to LC oscillators, and low power consumption and tran sistor count compared to ring-oscillator counterparts. The implemented VCO has an adjustable frequency range from 13.75 to 21.5 GHz and provides two c omplementary outputs. Total power consumption at 18.6 GHz is 130 mW, while the phase noise is -90.0 dBc/Hz measured at 1-MHz offset frequency.