Research On GaN Broadband High Efficiency Rf Power Amplifier

With the rapid development of wireless communication systems,RF power amplifiers have become indispensable components in communication systems in order to transmit modulated signals over long distances.In the wireless transceiver system,the signal must be amplified before being able to achieve the purpose of long-distance transmission.Therefore,the broadband and efficiency of power amplifier play an important role in the overall system stability and cooling costs.This demand has largely contributed to the research of broadband high efficiency power amplifier.In this thesis,broadband high-efficiency power amplifier is designed by adding a new broadband matching idea.First of all,a lot of literature review of the recent years are consulted.Research results of class F and broadband high-efficiency power amplifiers make great achievements and the latest developments are summarized.Secondly,it introduces the basic theory research of different broadband high efficiency power amplifier.The mathematic derivation of F type voltage waveform and current waveform are elaborated.The different broadband matching methods including broadband theory and simplified the real frequency technology have been analyzed.Especially some practical broadband matching methods including multi-branch impedance transformation and impedance grading are introduced and analyzed,which provided the theoretical support for the selection of the power amplifier design.Then this thesis uses different innovative methods to simulate the design of the two amplifiers are:In order to cover the working frequency bands of the three mobile carriers of China Mobile,China Telecom and China Unicom,power amplifiers are required to own broadband.A power amplifier(PA)with bandwidth 1.3-2.7 GHz is designed(fully covers the operating bands of the three mobile carriers).Measured results show that more than 68% efficiency is attained over a 75%bandwidth from 1.3 to 2.7 GHz.The output power is larger than 40.2 d Bm with gain varying from10 to 13 d B across the band.In this design,three-frequency point matching method is applied in order for broadband matching.High-efficiency is achieved by a specially designed impedance matching topology which realizes short-circuits of the second harmonics and open-circuits of the third harmonics at different frequencies.Then a 1.2-2.6 GHz bandwidth continuous PA is designed by using continuous class theory and fundamental step matching theory.The leakage efficiency reaches 60%-88%.The relativebandwidth reaches 73% and the average output power is above 10 W.Signal gain is 10-12 d B.Both of these design methods are highly innovative and their performance results have achieved superior levels of bandwidth and efficiency in particular.A number of key issues in Ga N power amplifiers that combine high efficiency and broadband problem are solved.The designed broadband high-efficiency Ga N power amplifier provides some new approaches and methods for the development of power amplifiers in 4G base stations.