Journal of Microwave Power and Electromagnetic Energy (JMPEE)
TITLE	Microwave Sensing Technique of Surface Hair-Line Cracks on Fast Moving Objects [PDF]
AUTHORS	T. Koryu Ishii 1988 23 3 176-182
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Abstract Fine cracks on a fast moving conducting surface were detected by the use of microwave radio responders. The interrogation angle was restricted to within oblique incidence angle only. The angle of incidence was with ± 0.5 degree from the surface. The speed of the moving interface was 20.23 m/s in the general direction of interrogating microwave beam. The size of one of the hair liar cracks investigated was 0.1 mm wide, 0.7 mm deep and 25 mm long. The crack was on a side surface of a motor coupling disc of 15.16 cm diameter. Experimental results on a fine crack examined at 10.525 GHs and 73 GHz are presented.