Simulation Analysis of Nondestructive Testing for Defects in Low-Loss Materials

High precision non-destructive testing of internal defects is crucial for ensuring structural safety. The traditional detection of high-frequency electromagnetic waves with normal incidence faces physical bottlenecks such as severe overlap between surface strong reflection and internal weak scattering signals, and the need for time-division multiplexing to remove clutter.

This article adopts a non-contact non-destructive testing strategy with Gaussian beam oblique incidence, taking typical low loss material fiberglass as the research object. Through full wave electromagnetic simulation, the propagation and scattering characteristics of Gaussian beam in a medium with a bottom ideal conductor (PEC) reflector are analyzed. Research has shown that oblique incidence irradiation can effectively achieve spatial separation between surface strong specular reflection and internal defect scattering, avoiding surface clutter interference; Efficient detection of deep layers within materials can be achieved through the use of Gaussian beams with longer waists; In addition, this scheme can significantly distinguish the shape and direction of strip-shaped air defects with different arrangement directions inside the medium through spatial scattering field characteristics.