A variable reflector for measurement of bulk electrical properties of materials using GPR

A variable reflector controlled by a GPR provides an improved method to measure bulk electrical properties of materials. For sample measurements, the GPR is placed on one side of a sample and the variable reflector on the opposite side. GPR trace data are then acquired with the reflector in ‘on’ and ‘off’ states. By differencing these measurements, we improve the ability to detect the desired reflection event. This method removes both the direct wave and clutter from the trace data, improving the quality of the refection event and our ability to accurately pick its arrival time and amplitude. In this paper, we describe the variable reflector developed for this application and present some examples of its use.