On the attenuation factor measurements of glass beads/magnetite mixtures and on the effective frequency evaluation by time domain reflectometry

Abstract

AhtracrSamples with different percentages (5-25%) of magnetite and different grains size ranges are analyzed by Time Domain Reflectometry (TDR) for deriving the bandwidth and the attenuation factor a . The spectral content of the signal changes as function of the material investigated. Indeed, the bandwidths narrow with the increasing of magnetite volume content of the sample. The spectral information coming from the bandwidth and the attenuations values were used to evaluate the effective frequency of the TDR signal. The attenuation factor values are obtained by. two different methods: i) wave amplitude at the second reflection, ii) electromagnetic parameters (evaluated with L-C-R meters) and TDR band widths. The two methods provide consistent a values within the experimental uncertainties. The agreement supports the possibility of measuring the attenuation factor from the second TDR reflection.