Thickness Reconstruction of Dielectric Coatings by the Use of Higher Order Impedance Boundary Conditions

Equivalent boundary conditions has been widely used for mathematical modeling in the wave problems [1]. The most common one is called Impedance Boundary Condition(IBC) where tangential components of the electric field are related to those of the magnetic fields. On the other hand, one of the important subject in inverse problem that is very important for automotive and defense industries is the reconstruction of thickness of coatings. In these framework, a new approach is proposed for the determination of variable thickness of coatings is proposed by employing the Higher Order Impedance Boundary Conditions (HIBC) which is defined in terms of thickness and physical properties of the layer [2]. To this aim, we first consider the HIBC modelling of the object which is made of a perfect conductor coated with dielectric layer whose thickness U is variable and small in terms of wavelength of incident wave. These conditions lead to approximate models that are close to the original one up to an 1:U