Differential-Mode Inline TLR Self-Calibration for the Characterization of Automotive Twisted-Pair Cables up to GHz Frequencies

The bandwidth demand for data transmission on copper cables increases rapidly. For this, cable models and their validation with highly accurate cable measurements are indispensable. In this paper, a solution for the characterization of the differential-mode characteristics of unshielded-twisted-pair cables is presented. Due to modal decoupling in both the measurement setup and twisted-pair cable, a reduced differential-mode calibration instead of a full mixed-mode calibration is required. To realize an inline reference plane, a differential-mode adaption of the TLR self-calibration is used. Lines of different lengths are used as calibration standards.