| The development of modern wireless communication systems is very rapid.Many new technologies and standards are constantly proposed,giving rise to many new RF technologies,such as Massive MIMO and 3D Beamforming,and the emergence of new technologies also puts forward new requirements for RF systems.As a key component in wireless transceiver system,RF power amplifier has an important impact on the stable communication and energy consumption of the whole RF link.Traditional power amplifier can no longer adapt to the high PAPR signals.Load modulated power amplifier with high back-off efficiency has become a popular research project.As one of the load modulated power amplifiers,the Outphasing power amplifier(OPA)has high backoff efficiency.Therefore,it is of great importance to study the method of band expansion of Outphasing power amplifier to suit the application context of modern multi-mode and multi-band systems.The contents of this paper are as follows:1.The basic principle of Outphasing power combiner is introduced systematically.Firstly,the mathematical principle of OPA is proved by equation derivation,then the types of Outphasing power combiner are introduced,and the differences in principle and efficiency between different types,the advantages and disadvantages of existing combiner are analyzed,and the design methods of some dual band reactance elements are given.2.A new dual-band power combiner is proposed to extend the bandwidth of OPA.The combiner is based on the ± j X structure.The combiner working at 1.8GHz and 2.6GHz is realized by designing a multi resonant circuit.Based on the theory,a dual-band OPA is realized.The maximum efficiency in the range of 6d B power back off reaches 68% and 70% respectively,and the minimum efficiency exceeds 58%.The design method is complete,clear and practical.3.Considering the application background of modern radar communication,a frequency reconfigurable OPA,which can switch between 10 GHz and 16 GHz,is designed and implemented using GaAs pHEMT technology.The design of reconfigurable transmission line is realized by transistor switch,and the design dual-band combiner is realized by switching the equivalent electrical length of transmission line.The maximum efficiency exceeds 50% and the minimum efficiency exceeds 48% within the 6d B power backoff range. |
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