Design of the Class-E Power Amplifier Considering the Temperature Effect of the Transistor On-Resistance for Sensor Applications

This brief presents the analysis and compensation technique for the class-E power amplifier (PA) considering the temperature effect of the non-zero transistor on-resistance for sensor network applications. It is shown theoretically and by simulation that the output power level and efficiency decrease with the increase of the transistor on-resistance. The transistor biasing condition for achieving near-zero temperature dependence is derived. With this, a dynamic biasing technique is proposed to stabilize the output power of the PA over a wide temperature range. A prototype class-E PA was designed and fabricated in a 0.18-mu m CMOS process. Operating at 477 MHz, the PA has 4 output stages and the measured maximum output variation is about +/- 0.3 dB from -40 degrees C to 85 degrees C. This measurement has a good agreement with the theoretical analysis and simulation.