Sticks and platelets in 3D random mixtures [dielectric/magnetic systems]

Broadband adapted screens have been obtained from random mixtures of anisotropic materials. The optimized screens and mixture parameters were calculated by using a genetic algorithm. Above to a few GHz, the optimal arrangement is demonstrated to be a three layers stacking of random mixtures made of conducting sticks. For each mixture the relevant parameters are the depolarizing factors of the sticks, that is their aspect ratio. Around 1 GHz, adapted screens are eventually obtained from insulated ferromagnetic platelets.