Time-Domain Reflectometry Using Scattering Parameters and a De-Embedding Application

Abstract : Time-Domain Reflectometry (TDR) has widespread use within the microwave industry as a primary investigation tool. Conventional TDRs utilize a pulse as the standard source to excite the device under test (DUT) and provide information of the DUT7s characteristic in a strictly time-domain sense. This information is not readily available for processing and hence somewhat limits the scope of usage. In this work, a TDR is simulated by using measured values of scattering parameters and a source which can be specified by the user. It achieves the latter by modelling the excitation source as a regular trapezoid and allows the user to vary the rise time and pulsewidth as the response of the DUT is observed. This technique was utilized in solving the 'de-embedding' problem where the effects of the connector between the measuring set and the DUT were effectively removed. The resulting waveform represented the response of the DUT alone and not the DUT/connector composite. Keywords include: S-parameter TDR; Scattering parameter; and Time-domain reflectometry.