Exploring the Effect of Switch ON Resistance on the Performance of Various Class E Power Amplifier Topologies

Abstract

Although the working of class E Power Amplifiers (PA) based on various tuned circuits is very well presented in the referenced papers, the performance disparities due to non-idealities in switching device is not very well discussed. Moreover, there is a lack of comparative study of the same with respect to diverse class E PA topologies. Capturing the effect of parasitics of the switch correctly plays an important role in the PA design, as the design equations with parasitics are greatly affected. This paper aims to explore the impact of the saturation/ON resistance of the switching device on power amplifier performance parameters. The paper presents the analysis and comparison of various SMPA topologies based on the diverse tuned circuit networks. The analysis is done at 2.4 GHz Industrial, Scientific and Medical band (ISM). It is observed that with the variation of switch resistance in the ON state, the power added efficiency and the power delivered to the load indicates an inverse dependence. Furthermore, as the saturation resistance increases more harmonics are observed at the load which in turn increases total harmonic distortion. The power loss in the switching device is also investigated and is found to have a direct relationship with the switch ON resistance.