Class E Power Amplifier Research And Design

Radio frequency transmitter is a key part of wireless communication system.As the core component of radio frequency transmitter,the power amplifier takes more than half power loss,so the design performance of power amplifier determines the output performance of radio frequency transmitter.Therefore,on the basis of meeting the basic design requirements,how to improve output power and efficiency of power amplifier is a difficulty of designing power amplifier.This thesis firstly describes the importance of wireless communication system in nowadays social life,briefly introduces the research status at home and abroad,key technical index and classification of E-class power amplifier,and elaborates its operating principles.Based on the two problems of large power consumption and low efficiency,which commonly existing in the research process of power amplifiers,the author puts forward two solutions.One of them is by adopting the mixed matching model of lumped element and distributed element and harmonic bidirectional traction technology,the optimal matching network is designed to improve the output power of the circuit.The other is adopting output feedback network to control bias voltage,improve the on-off transition efficiency of power amplifier tube and power-added efficiency of the circuit.On the basis of these,The design and simulation of two high-output and high-efficiency power amplifiers are completed in ADS and Cadence Virtuoso environments respectively.This paper mainly completes the following research contents:(1)Firstly,the reason of power loss in the process of signal transmission is analyzed.A hybrid matching model of lumped element and distributed element is adopted to design the best matching network of the whole circuit combined with harmonic bidirectional traction technology.In the meanwhile,introduces shunt grounding capacitor at the input and output of the circuit to improve the tunability of the design circuit Finally,the class E power amplifier with high efficiency and high output power is designed with ADS simulation software when the input signal power is 20 dBm,and the output power is 1.85 GHz,then the output power is 37.8 dBm,the gain is 18 dB and the power additional efficiency is 46.62%.(2)A class E power amplifier operating at 8.9 GHz with high efficiency and high gain is designed based on the analysis of a class E power amplifier with conventional cascode structure.The innovation of this design is to control the gate voltage of the cascode transistor by adding a feedback loop to the cascode output of the conventional cascode circuit,and to improve the conversion efficiency of the cascode circuit between turn-on and cut-off by controlling the gate voltage of the cascode transistor through the feedback loop.At the same time,the conventional single-stage amplifier model is abandoned at the input of the circuit,and the output impedance of the circuit is increased by using the thr-cascode circuit structure,thus the output gain of the whole circuit is increased.Finally,TSMC 1P6 M 180nm RF CMOS process is used to design the class E power amplifier.When the operating frequency is 8.9 GHz,the output power is 23.5 dBm,the gain is 24.5 dB and the power additional efficiency is 22.5%.