Detection of Defects in Film-Coated Metals and Non-Metallic Materials Based on Spoof Surface Plasmon Polaritons

A novel sensor based on spoof surface plasmon polaritons is presented to detect defects in film-coated metals and non-metallic materials. The sensor is a flexible strip that can be easily wound around various shapes of the material under test (MUT) and by scanning the surface of MUT with the designed sensor, the defects of the MUT can be detected. Since the sensitive area of the sensor is strip-shaped, the detection only needs to be scanned in one direction (most sensors need to scan in two orthogonal directions) which improves the detection speed and reduces the complexity of detection process. The detection are based on monitoring change of the transmission coefficient which is caused by the disturbation of electromagnetic field around the spoof surface plasmon polaritons. The sensor is flexible, sensitive and the detection speed is fast.