Research And Application Of On-wafer Nonlinear Testing Technology Of RF Power Devices For 5G Wireless Communication Technology

5G,which is the fifth generation of mobile communication technology,has become the current research hotspot in the field of communications.With the popularization of 5G technology,wireless communication technology continues to develop in the direction of high power and high frequency,and RF power devices have also been widely used.RF circuit design depends on the accurate representation of the device model,and RF on-wafer testing is the basis for the accurate characterization of device characteristics.The complete device test is not only the traditional small-signal S-parameter test,but also includes the device nonlinear characteristics test under largesignal excitation.Therefore,in this paper,based on a brief introduction to small signal S-parameters,the nonlinear test techniques for RF power devices are thoroughly investigated and discussed.The main points of the paper can be divided into the following sections:1.The on-wafer testing technology of RF power devices is briefly introduced,including small signal S-parameter and nonlinear tests and their test metrics,and key test instruments,such as vector network analyzers,oscilloscopes,and signal generator,are introduced.2.Different types of load-pull technology are compared and analyzed.For the problems of poor stability and slow tuning speed of active load-pull,an impedance tuning algorithm based on behavior level model based on Bayesian inference is proposed.The experimental results show that this technology can effectively reduce the number of iterations required in the process of synthesizing load impedance,improve the accuracy of impedance synthesis.3.The performance of HBTs under load mismatch has been tested and analyzed by real-time load-pull technology.The traditional test method is improved by using an impedance circle with the optimal impedance point as the center of the circle for load mismatch testing,and the calculation method of the impedance circle is also discussed and analyzed in detail.The experimental results show that the data obtained by the conventional method is deficient in assessing the effect of load mismatch on the device in practical applications.In addition,the power calibration algorithm is investigated in depth in conjunction with the test system used.4.In view of the increasing bandwidth of 5G modulation signal,this paper studies the two-tone test technology for broadband nonlinear characterization,and proposes a two-tone test system.Based on the test system,ATE test tool is written.At the same time,the principle of intermodulation distortion and the cause of IMD sideband asymmetry are analyzed.