Theory And Methods Of FBAR On-board Test

The advantages of high Q,low insertion loss,good out-of-band rejection,and high power capacity of thin film acoustic resonator?FBAR?filters enhance the demands of their market greatly after commercialization of 5 G mobile communications.With the increase demands of FBAR filter,its performance requirements are constantly improving,and the subsequent performance testing problems are also facing great challenges.This paper mainly proposes a design method of FBAR on-board test fixture and its calibration standard kit to provide a low-loss electrical connection between the device under teste?DUT?of the non-coaxial interface and the test instrument of the coaxial interface.A design method was proposed to quickly obtain the initial structural parameters of the on-board test fixture,and the test fixture designed by this method was tested and verified that it can provide a good initial value for the subsequent de-embedding calibration.The main factor affecting the test results of the FBAR on-board fixture test is the impedance mismatch,so from the point of view of the impedance matching of the test fixture,the structural parameters of the fixture were solved by combining the empirical formula with the micro-strip line calculation tool.To ensure the impedance matching of the test fixture,a transient simulation circuit TDR was established in the ADS to study the impedance matching of the micro-strip line,to give a method to verify the impedance matching of the micro-strip line and to solve the impedance mismatch of the micro-strip line.And then,the designed test fixture was verified by the method.Finally three FBAR filter chips with different center frequencies were selected as DUT respectively to do the probe test on-wafer?include DUT,Radio frequency probe table,and Vector network analyzer?and fixture test on-board?include DUT,test fixture and vector network analyzer?,and the S₁₂,S₂₁ curves of the two test results were compared,to verify the design of the test fixture.According to the advantages and characteristics of the existing calibration methods,a method of segment de-embedding calibration?100 MHz-2GHz:SOLT;2GHz-10GHz:TRL?was proposed,that is,the test data is segmental de-embedding calibrated.The calibration standard parts were designed according to the selected frequency band.And then,the simulation verifications of the designed de-embedding calibrations standards were done by combining the simulation software of ADS with HFSS.And last,the calibration standards were fabricated.The error model was corrected,the coefficient of the error term in the error model was extracted,and the expressions of the DUT S parameter containing the error term were derived.According to the internal structure of the vector network analyzer?VNA?and the test fixture,the signal flow diagram with systematic error term coefficient was established,and the fixture effect was embedded into the original error model.The relation expressions of the error term coefficient-the VNA test results,and DUT S parameter-the error term coefficient are defined by mathematical derivation according to the error model signal flow diagram.And then the error term coefficient was extracted,and the DUT S parameter containing the error term coefficient was derived to prepare for the programming of calibration software.The design of Calibration software and analysis of calibration results.The python programming language was used to write the DUT parameter calibration software,and the extended package was designed by using the PyQt5 graphical interface of the python,and the interactive interface between the software and the user was designed to realize the rapid calibration of the test data of the DUT test fixture.