4.9-GHz low-phase-noise transformer-based superharmonic-coupled GaInP/GaAs HBT QVCO

Abstract

The low-phase-noise GaInP/GaAs heterojunction bipolar transistor (HBT) quadrature voltage controlled-oscillator (QVCO) using transformer-based superharmonic coupling topology is demonstrated for the first time. The fully integrated QVCO at 4.87 GHz has phase noise of -131 dBc/Hz at 1-MHz offset frequency, output power of -4 dBm and the figure of merit (FOM) -198 dBc/Hz. The state-of-the-art phase noise FOM is attributed to the superior GaInP/GaAs HBT low-frequency device noise and the high quality transformer formed on the GaAs semi-insulating substrate.