The sensitivity of four-coil electromagnetic transducer to electric conductivity anisotropy

The problem of interaction of electromagnetic waves with anisotropic conductive media was considered in some earlier works. But it is not possible to use this results for analyzing of the eddy current probe signals. The known theoretical models cannot describe new electromagnetic multi-coil probes especially in the case when the probe is located under anisotropic conductive material. In this paper we present the theoretical investigation of the influence of electric conductivity anisotropy on the output signal of four-coil displaced probe