Research On High Efficiency Wideband Filter Power Amplifier With Coupled Terminal Lines

With the development and application of 5G communication technology,the new generation of communication standards require modern communication systems to develop in the direction of miniaturization and integration.In the traditional RF communication system,the power amplifier and the filter are two independent modules,which are connected by a cascade.However,this simple connection mode will introduce additional insertion loss,reduce the efficiency of the overall communication system,and will increase the circuit area and reduce the space utilization rate.By taking the filtering structure as a part of the power amplifier output matching network to carry out the filtering and power amplifier joint design instead of the simple cascaded connection mode,it can not only avoid the insertion loss,but also realize the integration of the system,and meet the requirements of modern communication system.Therefore,the device with the function of signal amplification and filtering fusion has high research significance and application value,and has been widely concerned.Based on this research background,an end-coupled line filter structure is adopted in this thesis,and two filter power amplifier design schemes are proposed,and the feasibility and correctness of the schemes are verified by the measured results.The main innovative contents of this thesis are as follows:1.A Class F efficient filter power amplifier with working frequency of 2.2-2.6GHz is designed.Firstly,a harmonic control network based on the quarter-wavelength transmission line is proposed to control the second and third harmonics,in order to meet the conditions for the realization of Class F power amplifier.Then a kind of filter structure based on symmetric terminal coupling line is introduced,which has the function of impedance transformation.It can be directly involved in the design of power amplifier output matching network to realize the filtering characteristics.The measured results show that the power amplifier efficiency PAE is 50.2%to 57.6%,the output power Pout is 40.2-41.6dBm,and the large signal Gain is 8.1-11.7dB,which meets the design requirements of the power amplifier.Moreover,the inband small signal gain S21 is 14.1-16.3dB,S11 is less than-8dB,and the out-of-band suppression is greater than 30dB,indicating that the power amplifier has a high matching degree and good filtering characteristics.2.A wideband filter power amplifier with working frequency of 2.0-3.6GHz is designed.Firstly,a broadband design method of generalized quasi-Chebyshev low-pass matching network based on step transmission line is introduced,which can directly design the distributed parameter model according to the power amplifier design parameters,skipping the lumped parameter model transformation process,and simplifying the complexity of design and parameter calculation.Then combined with the filter structure based on symmetric terminal coupling line,the design of wideband filter power amplifier is completed.In a wide frequency band,S21 is greater than 11dB,S11 is less than-7dB,and the out-of-band suppression is greater than-35dB.The waveform is flat and has good filtering characteristics.The design schemes of the two filter power amplifiers proposed in this thesis have been verified,and the test results show that the signal amplification and filtering functions of the power amplifier are in line with the expectations,which provides new ideas and ideas for the research and design of new efficient broadband filter power amplifiers,and has good research and application value.