Microwave methods

Abstract

The electromagnetic microwave method of testing is less commonly used than other electrical NDT methods because of its comparatively limited range of applications and, except in its very basic form, its somewhat greater complexity of instrumentation. However, with the present trend in industry towards the replacement of metals by non-metallic materials and the increase in availability and the corresponding decrease in price of the more sophisticated electronic devices, the use of microwave testing should become more widespread. The microwave method is mainly used for testing dielectric materials in bulk and the surface and subsurface regions of metals. It has the advantage, shared with other electromagnetic techniques, that no contact is necessary between the probe and the object being tested. It is often possible to locate the probe at some distance from the object, which facilitates testing at high temperatures and also the inspection of moving objects.