Research On Reconfigurable Multi-band Asymmetrical Doherty RF Power Amplifier

With the continuous development of communication technology, the spectrum resources is limited,and spectrum resources are not fully utilized due to the principle of the fixing band allocation. Cognitiveradio system uses dynamic spectrum allocation mechanism, achieves "spectrum resource sharing" andimproves the spectrum efficiency in time and space. Cognitive radio system is characterized by flexible,intelligent, reconfigurability, and will make an important contribution for the future low-carbon energy. RFpower amplifier (PA) is regarded as the critical components of radio communication and the realization ofits reconfigurable capabilities will be a key step in the path of development of cognitive radio systems.This thesis studies the application of reconfigurable device in the matching network of RF PA.Furthermore, a new method to achieve the reconfigurable capabilities of PA is proposed. Two aspects ofsoftware simulation and hardware implementation are discussed for the full proof. The main content of thispaper are as follows:IPart1, we make a brief introduction about basic concepts and design methods of RF PA, and thenthe design methods of the current multi-band, multi-mode power amplifier are analyzed.Part2, the application of reconfigurable device in the design of PA is investigated. We propose areconfigurable switch by using PIN diodes to achieve the design and hardware implementation. The actualtest results of circuit meet the design requirements. Finally, a detailed analysis on multi-band matching andreconfigurable matching network is done.Part3, firstly, a new method is used to achieve the design of reconfigurable multi-band PA. At thesame time, target analysis and device selection is finished. Secondly, the power amplifier drives levelsimulation and debugging are introduced in detail. Finally, we focus on the overall process design of thefinal stage of reconfigurable multi-band amplifier. The reconfigurability design at the frequency of1750MHz,2100MHz, and2600MHz is achieved, and the maximum output power of40dBm is obtained.Part4, the design theory of Doherty PA is introduced at first. Following, the integration design ofDoherty PA structure based on the reconfigurable multi-band single amplifier is proposed. a propotype isdesign and fabricated. The experiment results show that the proposed PA can switch between1900MHz,2100MHz and2530MHz, the output power can reach to41-43dBm and the efficiency is38%-45%.Part5, asymmetric Doherty power amplifier is studied. For the specific design, a broadband coupler isused to obtain the unequal input power.