TDRI is a new and patented concept for non-invasive and potentially non-contact probing of moisture content of a range of materials. It uses a very low power signal to generate the transverse field of a parallel transmission line which probes the material. The effective frequency range is from approximately 1 to 5 GHz. While scalable in measurement depth from a few cm to 50 or so cm, dependence on the texture of some materials increases as penetration depth increases.
The technology has particular relevance to applications where penetration of the material is a disadvantage, eg. the food industry where non-contact and hence non-contaminating measurements are essential.