Research On On-wafer Measurement Of RF Power Devices

Radio-frequency on-wafer measurement is an important means to obtain power device parameters.In order to obtain accurate RF power device parameters,it is necessary to ensure the stability and reliability of RF on-wafer test system.The thesis mainly focuses on the calibration method optimization,error analysis and large signal load-pull test technology of RF on-wafer test technology.The main content of the thesis is divided into the following parts:1.Aiming at the problem of test error of TRL calibration method under large signal test.Based on the classical TRL calibration method,an improved TRL calibration method was proposed.A set of error terms was calculated for the test of thru calibration parts under different load conditions.When testing,use appropriate error terms for different load conditions.Using the modified TRL calibration method reduced the typical thru test error by 62.5% compared to the classical TRL calibration method.2.RF probe is a typical test device for RF on-wafer measurement.Research showed that different RF probes would affect the test results,which was generally referred to as probe residual.In the thesis,a theoretical method was presented to analyze the residual error of the probe by using the consistency of thru and line standard parts.The results showed that this method had a good characterization for quantization of residuals of different probes at 5～30GHz,and the influence of probe residuals on small signal test and large signal load-pull test was discussed.3.To solve the problem of existing active load-pull relying on high-power external signal sources in the area of high reflection coefficient,a new active load-pull structure was proposed.It could effectively improve the ability of synthesizing high reflection coefficient impedance under low output power at the load end by redirecting the signal from the device under test back to the device under test.Compared with the general open-loop active load-pull structure,the maximum reflection coefficient amplitude of the new load-pull structure was increased by 47.2% under the same restrictive conditions.