Influence of Flange, Frequency and Liftoff on Microwave Detection of Stress Induced Fatigue Cracks using Open-Ended Rectangular Waveguides

The influence of the waveguide flange, frequency of operation and liftoff on crack detection sensitivity was studied by using microwave nondestructive inspection methods. The presence of a flange at a waveguide aperture provided two extra signal peaks which increased crack detection sensitivity. The results showed that the optimal choice of these parameters could significantly enhance the crack detection sensitivity in practical applications