Interaction of an Open-Ended Rectangular Waveguide Probe With an Arbitrary-Shape Surface Crack in a Lossy Conductor

This paper presents a modeling technique to predict the output signal of an open-ended rectangular waveguide probe when scanning an arbitrary-shape crack in a lossy conductor with finite conductivity. The loss of the specimen is taken into account by using surface impedance at the surface. The technique discretizes the crack shape and applies the generalized scattering matrix technique to obtain the output signal. To validate the model proposed in this paper, the results of the proposed method are compared with the measurement results and those obtained using a finite-element code. The model is used to obtain appropriate inversion curves for determining crack depth measurement from the probe output signal.