This paper presents a beyond state-of-the-art, sweeping microwave asphalt radar mounted on a small radio controlled four-wheel-drive rover. The quasi-monostatic, remote-controllable radar operates at Ku-band and has an output power of +10 dBm. Detection follows the zero intermediate frequency principle. The sweep width allows for a depth resolution better than 10 mm. With its four microprocessors and laptop computer processing, the radar system can provide pavement permittivity data with an uncertainty close to 0.1. This is a considerable advancement when applying electromagnetic measurement techniques for applications where near surface or thin surface layer measurements are needed.
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.
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