Analytical Method to Check and Correct the TDR Impedance Profile of Low-Loss Transmission Lines

In this work, an analytical method is presented by means of which an obtained time domain reflectometry (TDR) measurement can be checked and corrected. The essential idea of the proposed procedure can be summarized briefly as follows: If an obtained result is correct, it must be possible to reproduce the TDR measurement exactly using an analytical TDR model. Here, observed deviations can be attributed to inaccuracies in the underlying TDR impedance profile. Particularly for lossless or at least low-loss transmission lines this approach is well applicable. This is demonstrated by the example of an unbalanced printed circuit board (PCB). The influence of multiple reflections is thus almost completely eliminated.