Scattering for Doubly Curved Functional Surfaces and Corresponding Planar Designs

We present a study of the performance degradation of electromagnetic absorbers when applied to doubly curved surfaces. The scattering from a perfectly conducting sphere coated with different types of single- and multilayer absorbers has been evaluated using analytic recursion expressions. A comparison of the effect of curvature on the absorber performance is presented for structures based on homogeneous resistive sheets and low permittivity spacers, circuit analog absorbers, bulk material absorbers, and ultra thin magnetic absorbers. A conclusion from this study is that bulk absorbers, based on lossy materials, are less sensitive to curvature than absorbers consisting of multiple layers of low permittivity spacers and resistive sheets.