Inspection of antennas embedded in smart composite structures using microwave NDT methods and X-ray computed tomography

Abstract

Antennas embedded in composites are key components in communication, radar, and sensing systems aboard aircrafts. The manufacturing complexities and in-service loading could compromise the integrity of the composite structure through defects within the antenna which undermine the structure utility. Therefore, Non-Destructive Testing (NDT) is needed to ensure antenna structure integrity pre- and post- commissioning. While X-Ray computed tomography (CT) is the gold standard method for these inspections as it provides high sensitivity and resolution, it is relatively expensive, slow, and inapplicable for in-situ inspection. This paper devises various Microwave NDT methods towards composite-embedded antenna inspection, unprecedentedly. By direct benchmarking against X-Ray CT, it will be demonstrated that a low-frequency resonant microwave probe provides a viable alternative to X-Ray CT with similar detection sensitivity (85 % defect detection in inspected samples). Moreover, the resonant microwave probe provides multifold enhancement in the sensitivity (>10x) compared to waveguide probes used conventionally for microwave NDT.