Electromagnetic properties of dry and water saturated basalt rock, 1-110 GHz

This paper reports on the measured electromagnetic properties of dry and water saturated basalt rock over a frequency range of 1-110 GHz. Tests were conducted in standard waveguides below 12 GHz and with free-space systems above 12 GHz. The basalt used in this investigation was found to be nonmagnetic. Measured relative permittivities for the dry basalt varied from approximately (8.19,-0.71) at 1.12 GHz to (6.80,-0.49) at 110 GHz. The porosity of the basalt was determined to be roughly 10%. Properties of water saturated basalt were also measured at several frequencies and compared to theoretical predictions based on a simple Maxwell-Garnett mixing theory. Finally, the potential of using microwave tomography on basalt rock was examined based on the resulting properties