Design of multi-layer mantle cloaks

In this work, we present a procedure to design mantle cloaking devices made of multi-layered metasurfaces. If properly engineered, such covers are able to individually cancel several modes contributing to the scattering from a given object and, differently from traditional mono-layer mantle cloaks, reduce the observability of objects that cannot be considered electrically small. The analytical formulation for cylindrical and spherical geometries is outlined and some examples are provided. Moreover, we propose a potential application of multi-layered mantle cloaks to reduce the blockage effect on antennas due passive supporting structures, without affecting their mechanical characteristics.