Non-invasive measurement of cable scattering parameters using dual inductive probes

Abstract

The scattering parameters of a cable can provide insights into its transmission and reflection characteristics, particularly for high-frequency signals. By analyzing these parameters, the health status of the cable may be assessed. Scattering parameters are typically obtained offline through invasive measurements. As such, this work outlines a non-invasive method for measuring cable scattering parameters using a dual inductive probe—because there is no physical connection between the test equipment and the cable, measurements can be performed in an online fashion. More importantly, this method requires no modifications to the existing configuration or impedance adaptation of the cable, making it suitable for a wide range of cable types. By accounting for the signal transmission characteristics of the probe, the proposed method can de-embed the probe response from the test results, ensuring that the non-invasive measurements are equivalent to those obtained via the traditional invasive methods. Experimental results demonstrate that the proposed method is applicable to RG58 cable, RVV cable, and twisted pairs. Beyond measuring the scattering parameters, the proposed configuration can also be adapted for impedance measurements.