Crack Detection on Metal Surfaces with an Array of Complimentary Split Ring Resonators

In this paper, an advanced sensor based on an array of Complementary Split Ring Resonators (CSRRs) has been presented for detecting metal fatigue, operating around at 10 GHz. The scanning mechanism of advanced sensor is based on perturbing the electromagnetic field in the vicinity of a negative effective dielectric permittivity, thus causing a large shift in resonant frequency. A metal fatigue is detected by using a periodic structure of CSRRs – a concept introduced here for first time-etched on ground plane. The electric field generated by the current on metal surface affects the transmission coefficient due to variation in lumped parameters of CSRR and leads to high sensitivity in detecting anomalies such as cracks in the Surface. The electromagnetic interaction of CSRR with small sized crack is analyzed with electromagnetic solver. In this paper, the shifting of transmission coefficient is observed by varying the width of the crack in the range of 25 m – 200 m. The simulated results show the feasibility of detecting very small cracks such as 25 m crack width, in the metallic surfaces.