Design Of High Efficiency And Linearity Power Amplifiers With Filtering Response

The improvement of people's living standards and the development of economy requires wireless communication technology to be more stable,higher speed and energy efficiency.The efficiency of power amplifier should be improved for saving energy,while maintaining its linearity,as power amplifier is an important device of wireless transmitter and always consumes the most power of the system.Meanwhile,the co-design methodology of RF devices,proposed by researchers and scholars recently,not only can improve power efficiency through the reduction of the power loss caused by device mismatch,but also helps miniaturizing power amplifier circuits.Base on the above,this paper mainly contains design of high-efficiency and linearity filtering power amplifiers,which can be divided into three parts:1.A Class-D power amplifier integrated with filtering balun is proposed.Aiming at the problem that the losses caused by the filters and baluns cascaded after Class D power amplifiers,this paper replace them by a high-Q hybrid cavity-microstrip structure filtering balun,which can be the output matching network of the Class-D power amplifier.This structure can be used for power amplifier impedance matching because of its impedance-transforming feature.Efficiency can keep at a high level with good frequency selectivity because of low insertion loss cavity-microstrip structure and reduction of cascaded lossy devices.Besides,cavitymicrostrip structure brings convenience to the integration with microstrip circuits.Proposed design has an advantage over those existing designs on circuit layout and reliability.Electromagnetic simulation results reveal the feasibility of this design.2.Power dividers with bandpass response are proposed.Design method of power divider integrated with bandpass filter is introduced in this paper,as power divider is a common passive device among power amplifiers.Unequal-and equal-filtering power dividers designed with two kinds of coupled-line bandpass filters are proposed in this paper,manufactured by LTCC and plane microstrip respectively.Electromagnetic simulation and experimental results confirm the feasibility of these two designs.One of these works has been published in 2018 IEEE MTTS International Wireless Symposium.3.A filtering Outphasing power amplifier is proposed.Using the co-design method of power divider and filter,novel power combiner with filtering response for Outphasing power amplifier is proposed.This power combiner can be the matching network of power amplifier while it has a bandpass frequency response.Outphasing power amplifier with proposed power combiner maintains high efficiency with a bandpass response.Back-off efficiency is improved as well.Power combiner as impedance matching circuit simplifies design of the circuit,which benefits miniaturization of power amplifier circuits.Electromagnetic simulation results reveal the feasibility of this design.