DIELECTRIC-PROPERTIES OF ICE AT MILLIMETER WAVELENGTHS

The use of radars to study the geophysical features in a polar environ ment requires reliable information about the relative complex dielectr ic permittivity, epsilon = epsilon' + i epsilon'', of ice at microwave and millimeter-wave frequencies. To address this requirement, epsilon of ice at millimeter wavelengths was obtained. using an interference technique. The interference pattern was produced by measuring the tran smittance through bubble-free ice slabs at normal incident angle as th e frequency was swept from 75 to 110 GHz. From the resulting interfere nce patterns, epsilon' was determined to be 3.17 +/- 0.05 and virtuall y independent of frequency. Frequency-dependent absorption loss was ob served such that epsilon'' increased from approximately 2.4 +/- 0.2 x 10(-3) to 4.0 +/- 9.2 x 10(-3) over the swept frequencies.