High resolution rapid microwave NDE of metal-composite joints using metallic reflectors

With the ever increasing usage of composites in civil, automative and aerospace industries, there has been an emphasis on developing a high resolution nondestructive evaluation (NDE) system. Microwave NDE techniques are well suited for inspection of dielectric materials such as composites because of the ability of electromagnetic waves to interact with these materials. While a far field microwave system has the capability of rapid, large area inspection at large stand-off distances, their resolution is limited due to diffraction limits. This research leverages the benefits of super-resolution property of time reversal focusing in a metallic reflector environment for enhancing the resolution of microwave far field NDE. Numerical simulations involving detecting disbonds in metal-composite joints validate the concept and demonstrate the benefits of the proposed approach.