A large-size coaxial waveguide time domain reflectometry unit for field use

A large-diameter open-ended coaxial waveguide has been interfaced with a commercially available time domain reflectometry (TDR) unit for field measurements of the dielectric properties of frozen and thawed soils and ice. A core barrel developed by the U.S. Army Cold Regions Research and Engineering Laboratory (CRREL) and modified for use in frozen soil was used to auger an annular slot around which the waveguide fits. Time domain traces of waveforms reflected from the sample-air interface and from a metal short are recorded in the field and later analyzed to give complex dielectric permittivity between 0.05 and 1.0 GHz.