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Refractive Index Measured Using a Frequency-Modulated Continuous-Wave Radar at 100 GHz

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This paper presents a technique to determine the refractive index of materials based on the Frequency-Modulated Continuous-Wave (FMCW) radar operating at the frequency band 75–110 GHz. The refractive index of a material is one of its physical constants that can characterize it, which makes its determination is of great interest. The 35-GHz bandwidth offers a theoretical resolution of 0.133 for a measurement support depth of 3.2 mm. The proposed study concerns solid and liquid materials state. A better resolution obtained by using a signal processing. This resolution is limited by the bandwidth. The results of materials refractive index experimental measurements demonstrate the performance of the proposed setup and the potential application for fast materials characterization.
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FMCW Radar; Refractive Index; Millimeter-Wave FM-CW; THz Radar; Submillimeter Wave Radar

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