Research On Broadband Matching Algorithm Applied To Power Amplifier

With the rapid development of mobile communication technology,the demand for power amplifiers(PA)is developing towards broadband high efficiency.When designing the circuit topology of a power amplifier in the traditional method,Designers basically use some CAD software,such as ADS,AWR for manual point-by-point matching by using lumped parameter elements or distributed parameter elements or mixed parameter elements in the Smith chart.This method lacks rigorous theoretical support,resulting in long design cycles and low efficiency,and usually does not get a good match.Therefore,broadband matching technology is needed to realize the design of broadband high-efficiency power amplifier.In this thesis,through the research of related technologies,through the research of related technologies,the simplified real-frequency algorithm is used to design the microwave amplifier broadband matching network.Instead of using impedance and admittance parameters,the algorithm uses a normalized scattering parameter matrix function to describe a two-port matching network,all of which are performed under the scattering parameters of the matching module.The optimization algorithm of SRFT is improved,and the Levenberg-Marquardt(LM)algorithm is used for nonlinear optimization.Therefore,the gain optimization of the matching system performs well in numerical values,it is faster and easier to use than other existing CAD algorithms.Through the optimization algorithm,the program is run on MATLAB to automatically generate the input-output matching network,and then the transmission power gain TPG of the matching network is optimized to achieve maximum power transmission,which reduces the complexity of the broadband matching network design and reduces the power consumption and cost.Then,based on the improved simplified real frequency algorithm,a method of load-pull contour classification for the design of broadband high efficiency power amplifier(PA)was studied by using support vector machine(SVM)technology.The SVM is used to classify load-pull profiles of different frequencies by establishing a classifier model,representing a functional relationship between harmonic impedance and load-pull profile.The accuracy of the classifier model of the load-pull profile was verified by design and testing.Finally,a broadband high-efficiency PA in the 2.5-3.5GHz band was designed based on the improved simplified real-frequency technology and the SVM algorithm,and the processing test was completed.The test results show that in the 2.5-3.5GHz working frequency band,the efficiency of PA is higher than 63%,the output power is greater than 40 d Bm,and the gain is greater than 11 d B.The measured maximum output power was 41.9 d Bm at 2.5GHz and the maximum drain efficiency measured at 2.9GHz was 74.1%.In addition,in the aspect of drain efficiency,the test results of the proposed optimization method are better than those of the simplified real frequency algorithm.When two other initial guesses are used for optimization,similar results are obtained.Based on the above results,the feasibility of the optimized simplified real-frequency algorithm and the support vector machine algorithm for designing broadband efficient PA was verified,which meets the design requirements.