An Evaluation of the Permittivity of Two Different Rock Types Using Microwave Resonator and Waveguide Cutoff Principles

Abstract Methods of measuring the complex permittivity of different rock types are demonstrated in the frequency range from 6 GHz to 17 GHz. The used methods are based on the cylindrical resonator and waveguide cutoff frequency principles. This study is part of a larger research project that aims to characterize the electrical properties of asphalt for road surveying purposes. The studied rock types are metavolcanic rock with intermediate composition and pegmatite. The permittivity values gained with the resonator method are 6.2 for the metavolcanic rock and 4.5 for the pegmatite rock type, whereas the imaginary parts are 0.04 and 0.02. The permittivity values gained with the cutoff frequency method are 6.17 and 4.76 respectively. A reference measurement was made only for the metavolcanic rock in a transmission configuration with two antennas and the permittivity result was 6.21. The three different methods provide consistent permittivity values and are suitable for reliable permittivity evaluation.

[1]  R. Knight,et al.  Dielectric constant as a predictor of porosity in dry volcanic rocks , 1999 .

[2]  P. Guillon,et al.  Dielectric resonators , 1988, Proceedings of the 42nd Annual Frequency Control Symposium, 1988..

[3]  Sixin Liu,et al.  Wide-band Rock and Ore Samples Complex Permittivity Measurement , 2011 .

[4]  Fawwaz T. Ulaby,et al.  Microwave dielectric properties of dry rocks , 1990 .

[5]  P. Vainikainen,et al.  Industrial microwave sensors , 1991, 1991 IEEE MTT-S International Microwave Symposium Digest.

[6]  Ziyuan Ouyang,et al.  Measurement of the complex permittivity of dry rocks and minerals: application of polythene dilution method and Lichtenecker’s mixture formulae , 2005 .

[7]  Andrzej Kraszewski,et al.  Microwave aquametry : electromagnetic wave interaction with water-containing materials , 1996 .

[8]  Alan P. Byrnes,et al.  Modeling Dielectric-constant values of Geologic Materials: An Aid to Ground-Penetrating Radar Data Collection and Interpretation , 2001 .

[9]  Nigel J. Cassidy,et al.  Chapter 2 – Electrical and Magnetic Properties of Rocks, Soils and Fluids , 2009 .

[10]  U. Hasar.  A microcontroller-based microwave free-space measurement system for permittivity determination of lossy liquid materials. , 2009, The Review of scientific instruments.

[11]  Simon Ramo,et al.  Fields and waves in modern radio , 1944 .

[12]  T. Scullion,et al.  Road evaluation with ground penetrating radar , 2000 .

[13]  Bo Li,et al.  Determination of the compaction of hot mix asphalt using high-frequency electromagnetic methods , 2013 .

[14]  George V. Keller,et al.  Rock and Mineral Properties , 2011 .

[15]  E. Nyfors,et al.  Cylindrical microwave resonator sensors for measuring materials under flow , 2000 .

[16]  P. Nurmi,et al.  Precambrian geology of Finland : key to the evolution of the fennoscandian shield , 2005 .