Transient scattering by a metal cylinder with cylindrically inhomogeneous dielectric material

Transient scattering by a metal cylinder covered with cylindrically inhomogeneous dielectric material is analyzed for radar application to nondestructive testing of reinforced concrete structures. First, inhomogeneous dielectric material that is a model of corrosion by rust is approximated by a cylindrical multi-layered medium, and a scattered field expression in frequency domain is derived. Next, time domain scattering response is calculated from the frequency domain data by using the inverse Fourier transform. Numerical result shows that the degree of corrosion can be evaluated by the transient response from the reinforced bar in concrete structure.