Compensation of Performance Degradation due to Thermal Effects in GaN LNA Using Dynamic Bias

This paper investigates the possibilities of using a dynamic bias control scheme for a low noise amplifier to compensate for performance degradation due to thermal effects. The study was performed by characterization of bias voltage and temperature dependence between −25°C to 75°C of a GaN MMIC LNA. The performance, in terms of gain, linearity and noise, degraded, at elevated chip temperatures. Nonlinear behavioral models were developed and used to predict performance for different bias and temperature conditions. Bias conditions to achieve constant gain and noise figure versus temperature are determined. Enhanced RF performance, with improved gain and linearity is demonstrated and is shown to require increased power and involves a trade-off between improving noise figure and gain.