An inverse technique to evaluate thickness and permittivity using reflection of plane wave from inhomogeneous dielectrics

This paper presents an easy to use method to estimate the thickness and permittivity of layered dielectrics. The reflection spectrum of plane electromagnetic wave incident upon multiple layers of dielectrics is analysed to determine the thickness and dielectric constant of one of the layers in a multi layered dielectrics system. The iterative procedure minimises the error between measured and computed spectrum. The minimisation is carried out using non-linear least square technique. Results obtained for layers of acrylic sheets are excellent.