Magnetic Energy Harvesting and Concentration at a Distance by Transformation Optics

Abstract

Based on transformation optics, we introduce a magnetic shell with which one can harvest magnetic energy and distribute it as desired in space with unprecedented efficiency at an arbitrary scale. It allows a very large concentration of magnetic energy in a free space region, which can be used for increasing the sensitivity of magnetic sensors, and the transfer of magnetic energy from a source to a given distant point separated by empty space, with possible applications in wireless transmission of energy.

Manipulating DC Currents with Bilayer Bulk Natural Materials

“…Recently, many significant achievements have been made in the manipulation of magnetostatic field [10][11][12][13][14][15] , thermal conduction [16][17][18][19] , and electrostatic field [20][21][22][23][24] . In 2007, Wood and Pendry proposed a dc metamaterial that pointed the way towards the design of static magnetic cloak [10] , and the dc metamaterial was experimentally verified soon afterwards [11] .…”

“…Recently, the dc magnetic cloak is theoretically investigated [12] and experimentally realized using superconductors and ferromagnetic materials [13,14] . By using the same materials as dc magnetic cloak, the theoretical realization of a dc magnetic concentrator is also demonstrated [15] . On the basis of form invariance of the heat conduction equation, transformation thermodynamics is investigated to manipulate diffusive heat flow [16] ; through tailoring inhomogeneity and anisotropy of conductivities, transient thermal cloaking has been experimentally demonstrated [17] .…”

“…Besides making objects invisible [1][2][3][4] , many other novel devices are rapidly emerging, with a representative one being a concentrator [5,6] that can enhance the energy density of incident waves in a given area. In addition to manipulation of EM waves [1][2][3][4][5][6] , the theoretical tool of coordinate transformation has been extended to other areas of physics (such as acoustic waves [7] , matter waves [8] and elastic waves [9] ).Recently, many significant achievements have been made in the manipulation of magnetostatic field [10][11][12][13][14][15] , thermal conduction [16][17][18][19] , and electrostatic field [20][21][22][23][24] . In 2007, Wood and Pendry proposed a dc metamaterial that pointed the way towards the design of static magnetic cloak [10] , and the dc metamaterial was experimentally verified soon afterwards [11] .…”

Dc Magnetic Concentrator and Omnidirectional Cascaded Cloak by Using Only One or Two Homogeneous Anisotropic Materials of Positive Permeability

“…Very recently, some DC magnetic lenses/concentrators have been designed based on transformation optics (TO) [12][13][14]. TO is a powerful theoretical tool that can be used to control the trace of electromagnetic waves and also the static electric or magnetic field.…”

“…TO is a powerful theoretical tool that can be used to control the trace of electromagnetic waves and also the static electric or magnetic field. A DC magnetic energy harvesting device, which can create an enhanced static magnetic field of high uniformity in free space, has been designed by TO [12]. However, it still needs some anisotropic medium whose permeability is zero in one principle direction and infinite in the other principle direction.…”