| Radio-frequency power amplifier?RF PA?is one of the most critical building blocks in radio transmitters and is also the most power-hungry component in the RF front end.To decrease the power consumption and heat sink requirements in wireless communication systems,various efficiency-boosting techniques have been developed and extensively investigated.Among these techniques,the class-F and class-F-1?inverse F?PAs have been the leading candidates by virtue of high efficiency,less operating frequency limitation and high power capacity.However,The intrinsic and extrinsic parasitics of transistors will affect the realized class-F and class-F-1 PA performance through disturbing harmonic load serverely.To overcome this issue,a more general and simple distributed parasitic-compensation technique for class-F and class-F-1 PAs is presented to compensate for any given parasitic parameters of the packaged transistors accurately.For experimental validations,2.14GHz class-F and class-F-1 PAs are designed.The measured maximum power-added-efficiency?PAE?of 80.2%for the class-F mode and 79.1%for the class-F-1 mode are achieved,respectively.For the purpose of setting forth the design procedure of class-F and class-F-1systematically and detailedly,this paper introduces performance metrics,general design flow,technology roadmap of RF PA,as well as the fundamental principles of the classic tuned load PA at first.Then,starting from power balance considerations,the harmonic termination impedance design requirments of class-F and class-F-1 will be clarified under the unifying theory of the harmonic tuned PA.Next,the circuit principle of proposed parasitics-compensation technique base on L-shaped trassimission line is interpreted and the corresponding mathematical deduce of design parameters is also presented.At last,the whole design process including the output matching network,biasing network and input matching network and the corresponding simulation results is shown. |
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