Reflection ellipsometry for in-situ measurements of complex permittivity and thickness of a single-layer material at microwave frequencies : theory and experiments

For in-situ measurement of the complex permittivity of planar materials, we have developed a free-space experimental setup based on reflection ellipsometry and extended to microwave frequencies. Different angles of incidence were studied in the range [35 ; 50°]. Original numerical methods, derived from analytical relations based on contour line charts and least-square optimization, allow to highlight the influence of measurement uncertainties. Novel developments concerning the simultaneous determination of both complex permittivity and thickness of a single-layer sample are shown.