Output signal prediction of an open-ended coaxial probe when scanning an arbitrary shape surface cracks in metals

A sub-domain method of moment formulation is proposed to model the problem of an open-ended coaxial probe radiating into a conducting metal with a surface-breaking crack. As opposed to the conventional model, the proposed formulation is capable of treating effectively the unknown magnetic current over the arbitrary shaped common aperture. This feature will remarkably improve the computation time, resulting in a fast prediction of probe output signal. Results are given for cracks with rectangular and elliptical shapes. The accuracy of the model will be demonstrated by comparing the theoretical results with those obtained using a commercial finite integration technique code.