DC MAGNETIC CONCENTRATOR AND OMNIDIRECTIONAL CASCADED CLOAK BY USING ONLY ONE OR TWO HOMOGENEOUS ANISOTROPIC MATERIALS OF POSITIVE PERMEABILITY

A novel concentrator for static magnetic fleld enhancement is proposed and designed utilizing transformation optics. Compared with other devices for static magnetic fleld enhancement, our device has many good features: flrst, our concentrator can achieve a DC magnetic fleld enhancement in a relatively large free space with high uniformity. Secondly, our concentrator is composed by only one or two homogenous anisotropic materials with principal value greater than zero (without any inflnitely large or zero value), which can be achieved by using currently available materials. Thirdly, the geometrical shape of the proposed device determines the enhancement factor and the permeability of the device. After choosing suitable geometrical parameters, we can obtain a concentration with a suitable enhancement factor and a material requirement that is easily achievable. The proposed concentrator will have many important applications in many areas (e.g., magnetic resonance imaging and magnetic sensors). Based on the same theoretical model, we also proposed a cascaded shielding device cloak for static magnetic flelds. The proposed DC magnetic shielding device can be realized without using any material of zero permeability, and will have potential applications in, e.g., hiding a metallic object from being detected by a metal locator.