An HBT noise model valid up to transit frequency

Abstract

A comprehensive HBT noise model for circuit simulation is presented that describes the microwave noise behavior up to the transit frequency. It is based on diode noise theory, and requires only the small-signal equivalent circuit, including the thermal resistance, and the dc bias point. A main feature is correlation of the shot-noise sources at the pn junctions. The model is verified by measurements of the four noise parameters of an InGaP/GaAs HBT, varying frequency and bias conditions.