Abstract:
A probe adapted for use with a time domain reflectrometry device in primarily measuring the moisture content in soils and other mediums. This probe can however be used in may differing measurement applications involving materials of specific dielectric constants as well as apparent dielectric constants that are derived from a matrix of several differing dielectrics. In the probe according to the present invention, the inner core of the probe is composed of an inner conductive element, a conductor that is used to transmit a broadband pulse. A dielectric liquid, solid or gel surrounds this inner conductive core, and assists in retaining broadband signal strength. The dielectric material is then encased in a metallic outer shell that serves as a protective housing for the probe. This outer shell is electronically transparent to the electromagnetic pulse transmitted by the active inner conductive core and surrounding dielectric. The outer shell is preferably made of stainless steel, but can be made of other materials as they serve to protect the inner dielectric material and conductive core. This combination of features allows a broadband pulse transmitted through the probe to penetrate into the material being measured, returning a much larger reflection feature upon reaching probe end points, while protecting the dielectric-coated transmission elements inside.