A passive DC magnetic concentrator is designed with transformation optics (TO) and realized by meta-materials. The passive DC magnetic concentrator, based on space compression transformation, can greatly enhance the magnetic field in a free space region, which can be used for e.g. improving the sensitivity of magnetic sensors and increasing the efficiency of wireless energy transmission. The magnetic property of the medium obtained by TO is extremely anisotropic. To solve this, we use magnetic meta-materials made of alternated high-permeability ferromagnetic (HPF) materials and high-temperature superconductor (HTS) materials. We optimize our structure by conducting simulations using the finite element method (FEM), and experimentally demonstrate a strong, 4.74-time enhancement of the DC magnetic field by our meta-material magnetic concentrator. We also demonstrate that a simplified structure with only HPF materials working at room temperature could still give 3.84-time enhancement of the DC magnetic field. The experimental results are in good agreement with the numerical simulations based on FEM.
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