| dc.description.abstract | Due to the rapid advancement in high technology, the design of instrument structures has become increasingly complex, requiring the use of fixtures to interconnect and assemble multiple components. When signals pass through these fixtures, they can experience attenuation and distortion at different frequencies, resulting in measurement inaccuracies. Scattering parameters are indicators used to evaluate the performance of instruments or transmission lines. They are typically measured using a network analyzer. The measurement results include the effects of both the instrument itself and the connecting fixtures. If one intends to assess the transmission performance of the instrument while excluding the influence of the fixtures, it becomes necessary to employ calibration techniques to remove the effects of the fixtures from the measurement results. This paper extends the conventional two-port fixture characterization method to a four-port configuration, presenting a novel approach for four-port fixture characterization. Since the frequency domain data, represented by S-parameters, measured by a network analyzer can be converted to time domain data obtained from reflectometer time-domain reflectometry (TDR) measurements, our method first converts the S-parameters of a 2x-Thru structure to TDR data. Then, using the time domain gating method, we separate the S-parameters corresponding to the two sides of the fixture. The remaining S-parameters are calculated using Mason’s gain formula. Finally, through the de-embedding process, the S-parameters are transformed into T-parameters, and the fixture effects are removed using matrix operations, yielding the S-parameters of the device under test (DUT). The proposed method will be compared with the Automatic Fixture Removal (AFR) algorithm developed by the renowned company Keysight Technologies to validate its effectiveness. | en_US |