Research On GaN High Efficiency Power Amplifier

RF power amplifier (PA) plays a very important role in the signal transmitter of wirelesscommunication system. It takes85%power consumption of the whole system, whoseworking bandwidth largely depend on the PA too. As modern communication data boostsand people use mobile terminal more and more often, how to improve efficiency tooprolong the use time of equipment, how to extend working bandwidth to improve capacityand speed of data transmit, these two problems have became popular among the RFresearch field. Based on the need of reality application, some research about the highefficiency and broadband RFPA was did.This paper first introduces the background and reality meaning of this issue, somedevelopment situation of GaN semiconductor, high efficiency and broadband RFPA both inchina and abroad were overviewed. Then some basic knowledge of RFPA was explained,including classification, main characteristics, concept of broadband RFPA, microstrip linebasic theory and impedance matching technology. The influence of parasitic parameters tohigh efficiency PA was analyzed too. The narrowband high efficiency PA was designed andtested in the forth chapter, the relationship between nonlinear output capacitor Coutof GaNHEMT and efficiency was analyzed through a model. By adopting a series of improvedmethods, DC bias circuit, harmonic control circuit and impedance matching circuit weredesigned and simulated. A high efficiency PA was obtained with bandwidth of2.09-2.19GHz, output efficiency higher than75%, output power higher than40dBm. In thefifth chapter, the broadband high efficiency PA was designed and tested, with the nonlinearoutput capacitor Cout, the high efficiency harmonic impedance area can be enlarged, the keypoint is the design of bias circuit, harmonic and fundamental wave impedance match at thesame time. A high efficiency broadband PA was made with bandwidth of2-3GHz, outputefficiency higher than65%, output power higher than40dBm.