Design And Research Of High Efficiency Class-E Power Amplifier Based On GaN HEMT

High efficiency is an eternal target in microwave power amplifier(PA)design.With the development of global wireless communication technology,users are demanding more and more energy consumption.Wireless RF transmitter is the key part of wireless communication hardware systems,and PA is the main energy dissipation unit in wireless RF transmitters.Improving the efficiency of the PA can effectively reduce the power consumption of system.Class E power amplifier is one of switching mode PAs.Its theoretical efficiency can reach 100%,which effectively solves the problem of insufficient efficiency of linear PAs.This paper first introduces the research history and progress of transistor technology and class E PAs,and expounds the basic theories such as classification,property index and composition of power amplifiers.Then,this article builds the circuit of class E PA based on switching mode PAs,and quantitatively derives the design formula of each component of load network.Subsequently,a 2.2GHz class E PA with a satellite measurement and control band was designed using a GaN transistor.The simulation results show that the drain voltage and current waveforms basically conform to class E,except existing a partial overlap.To solve this problem,a "de-packaged circuit" is added at drain of transistor,then an ideal class E waveform is observed at the equivalent switch surface.Next,a micro-strip line class E PA working at 2.2GHz is designed.By means of part harmonics suppression and drain inductance effect enhancing,the load network of lumped components is converted into micro-strip lines,which has the functions of harmonic suppression and impedance transformation.The measured results demonstrate more than 60% PAE and 40 dBm output power in 2.1GHz-2.3GHz.At center frequency,67.3% PAE,41.03 dBm output power,and 15 dB gain are achieved.Finally,this paper points out the problems such as linearity existed in the work,and analyzes the direction of the further optimization,and the future development of GaN class E power amplifiers is prospected.