Double-dipolar artificial dielectrics as radiofrequency absorbing materials

An arti/icial dielectric consisting o/ a bidimensional lattice o/ electric and magnetic minimum scattering antennas is proposed. The lattice can be geometrically arranged t'n severa! ways, /or example as a Yee-like celi where a repeated structure is realized with a matched magnetic loop placed at the center of /our matched electric dipoles occupying the corners of a rectangle. Such a planar array can be designed to constitute a virtually per/ect absorber /or à monochromatic wave t'mpinging at norma! incidence. The arti/icial dielectric is studied by means o/ a mt'xed microscopt'c/macroscopic approach allowing to compute the equivalent permitti'vity and permeability o/ the metamaterial automatically taking into account dipole-dt'pole interactions. It is demonstrated /or a dilute double-dipolar medium that both permittivity and permeability bave a unitary real part and imaginary parts such to allow a full absorption of the impinging electromagnetic power. The dependence o/ the absorbed electromagnetic power on the lattice geometry is investigated in terms o/ the ratio between the total power t'nddent on a given surface o/ the dielectric and that absorbed by it, showing that an interval o/ lattice spacings is available where that ratio is close to one.