ULTRASONIC SURFACE-WAVES ABOVE RECTANGULAR-GROOVE GRATINGS

A modal model, initially developed to modelize diffraction of electrom agnetic waves by rectangular-groove gratings, is used to describe ultr asonic surface waves above the same structures in air. A simple analyt ical formulation which provides results comparable to the modal method is presented. Measurements performed on ultrasonic surface waves are compared to predictions obtained with the simplified formulation and t he modal model. (C) 1998 Acoustical Society of America.