Monostatic and Thickness-Independent Material Characterisation based on Microwave Ellipsometry

Jan Barowski, Thorsten Schultze, Ingolf Willms, Ilona Rolfes

Ger­man Micro­wa­ve Con­fe­rence (GeMiC 2016), pp. 449-452, doi: 10.1109/GEMIC.2016.7461652, Bochum, Ger­ma­ny, March 14-16, 2016


Material characterization utilizing microwave ellipsometry is based on the fact that the reflection coefficents of a wave impinging on a material depend on the incident fields polarization. Due to multiple reflections that occur in case of a material slab with finite dimensions these coefficients also strongly depend on the materials thickness. This paper describes an approach to determine the electromagnetic properties of a material under test by applying an ellipsometric measurement without knowledge of the materials thickness. The paper shows that the additional measurement of the transmission coefficents allows to perform an exact measurement of the complex permittivity since the thickness dependencies in reflection and transmission coefficents cancel each other. The measurements are done in the frequency range from 22 GHz to 26 GHz by using a vector network analyzer setup with a conical horn antenna.

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