| With the continuous replacement and advancement of wireless communication technologies,future communication systems need to develop towards wider bandwidth and faster speeds.As the main component of the radio frequency front-end system,the performance of the power amplifier will directly determine the transmission quality of the entire system.In order to reduce the occupied area and production cost,increase the data transmission rate,and reduce the power consumption,it is necessary to configure a broadband high-efficiency power amplifier in the radio frequency front end.This thesis designs two high-performance compact power amplifiers with different structures by analyzing and researching traditional broadband power amplifiers and high-efficiency power amplifiers.Firstly,by referring to the domestic and foreign literatures in related literatures,the research status of the broadband high-efficiency power amplifiers have presented,and the shortcomings and problems of the existing broadband high-efficiency power amplifier circuits are dug.Secondly,the types of power amplifiers,performance indexes,improved linearity and efficiency enhancement techniques are introduced,and then theories of the latest proposal broadband high-efficiency hybrid class EFJ power amplifier is elaborated in detail.The existing hybrid class EFJ power amplifiers designs are based on the design theory of the traditional hybrid class EFJ power amplifiers.Regarding the design of output matching circuit,it mainly contains two parts before and after,which are harmonic network and fundamental network respectively,which greatly increases the design complexity and production cost of class EFJ power amplifiers.This thesis has improved and perfected this issue,and finally completed two hybrid class EFJ power amplifiers with different structures.(1)This thesis proposes a T-shaped two-port network based on parallel sector microstrip lines for the design of output matching circuits.The structure not only has the function of impedance conversion,but also has the function of harmonic control,which realizes the combination of harmonic control and impedance conversion.The use of the proposed structure effectively reduces the complexity and occupies area of class EFJ design,and saves the production cost.Test results show that the drain efficiency achieved by this class EFJ power amplifier is 61%-71%in the 1.4-3.8 GHz operating band,with an output power of 40.3-41.8 d Bm and an area of 53×47 mm~2.(2)In order to further increase the bandwidth and design versatility,a T-shaped two-port network based on the coupling structure is proposed for the design of the output matching circuit,which can flexibly change the output matching circuit impedance value by controlling the value of the coupling coefficient K to meet the optimal impedance range required by the class EFJ power amplifiers.This leads to more flexible and convenient design.Measurement results show that the drain efficiency achieved by this class EFJ power amplifier is 62%-73%in the 0.8-3.0 GHz operating band,the output power is 40.0-42.2 d Bm,and the area is 52×40 mm~2.Compared with the previous designed circuit,the relative bandwidth of this circuit is increased by 23%,the harmonic control capability is stronger,and the area is further reduced,thus further reducing the production cost.In addition to the above two low-frequency power amplifiers,this thesis also designs a power amplifier for the millimeter-wave.The working frequency band of the power amplifier is 71-76 GHz,with 0.1um Ga N HEMT,and composed of four-stage amplifier.The final simulation results show that the P1d B compression point of the proposed power amplifier is 24.366-25.553 d Bm,the saturated output power is 29.2-29.6 d Bm in 71-76 GHz,and overall circuit size is 4.8×1.7 mm~2. |
