Trapped air metamaterial concept for ultrasonic sub-wavelength imaging in water

摘要

( ) The two additively-manufactured layers which, when placed together, form the TAM; ( ) a sketch representing four unit cells of holes of the TAM. Here  = 1.2 mm, mm, and  mm, the values used for FEM simulations. Air was trapped within the polymer substrate as shown by the black areas in the zoomed diagram of the embedded air cavity depicted to the right, with 0.1 mm and  mm. Note that the depth of the air cavity is given by .