Low-frequency ultrasonic filters of finite and infinite periodic structure

Abstract In the present work we compare the low-frequency ultrasonic through-transmission in two different media of a doubly-periodic internal structure. In the first medium the doubly-periodic array is infinite in the transverse direction, while in the second one the number of obstacles is finite. The obtained theoretical results are compared with the data of the natural experiments performed with a steel specimen. It is evaluated how long may be the finite structure in the transverse direction, to provide in practice efficient acoustic filtering close to the analogous theoretical infinite geometry.