The Influence of Microwave Pulse Width on the Thermal Burnout Effect of an LNA Constructed by the SiGe HBT

Abstract

This paper presents the influence of the pulse width on the thermal burnout effect of a low-noise amplifier (LNA) constructed by a silicon–germanium heterojunction bipolar transistor (SiGe HBT) when it is injected by microwave pulses. Based on the characteristics of microwave pulses and the structure of the SiGe HBT, a theoretical model to predict the impact of the pulse width and power on the thermal burnout effect of the LNA is established by solving the heat conduction equation. The derivation of the theoretical model requires the pulse width less than a microsecond level. Using at least two groups of simulated or measured results to fit the coefficients, the proposed theoretical model can predict the other effect of the pulse width, which can greatly reduce the experimental costs and guide the rational selection of the pulse width in numerical simulations. At last, the theoretical model is verified by numerical simulations and experimental measurements. The results show that within the scope of pulse width (less than the microsecond level) the burnout power threshold can be effectively reduced by increasing the pulse width.