A time domain transmission measurement system for dielectric characterizations

Bianca Will, Michael Gerding, Christian Schulz, Christoph Baer, Thomas Musch, Ilona Rolfes

International Journal of Microwave and Wireless Technologies, Vol. 4, Issue 3, pp. 349-355, June 2012


Delay time measurements are a commonly used technique for the characterization of dielectric materials. Especially with regard to the characterization of water–solid mixtures like soil or grain delay time measurements, e.g., time domain reflectometry offers a powerful method. However, the accuracy of reflection measurements is limited due to multiple reflections caused by inhomogenities of the environmental material of the sensor. This contribution deals with an improved sensor design based on time domain transmission (TDT) measurements. Thus, the first received impulse includes the necessary information. Multiple reflections are received at later time steps and their influence on the measurement accuracy is nearly negligible. To improve the performance and the applicability of the designed sensor, a cost–efficient TDT system is designed, which is integrated in the sensor. Additionally, a so-called “concentric reversion coupler” is used, which offers the possibility to perform TDT measurements without the necessity of external measuring ports.


tags: dielectric materials, TDT, time domain transmission