An Impedance-Permeability Self-Resonance of Inductance Coil with Metamaterials

An impedance-permeability (Z-) resonance phenomenon is firstly founded and numerically demonstrated when electromagnetic metamaterials with negative permeability are firstly introduced into inductance coil. Numerical results reveal that the impedance-permeability relationship exhibits an extraordinary self-resonant phenomenon at a certain negative value of relative permeability, which is related to the dimensions of the core but nearly independent to the coil size. Such a mechanism is proposed to increase the sensitivity of eddy current (EC) sensors up to about 270 times, offering a new method to greatly improve the sensitivity of EC sensors and the spatial resolution with micrometer scale.