Characterizing attenuation in 3-D-printed ultrasonic Metamaterials

3-D-printed Metamaterials offer new capabilities for manipulating ultrasonic waves in the MHz regime, promising new devices, such as lenses and phase shifters, in imaging and power applications. The losses present in such devices can be critical to their practical realization, yet the factors contributing to attenuation in metamaterials remain underexplored. This study presents a numerical and experimental analysis to link the total attenuation expressed by 3-D-printed metamaterials to their unit cell design and the 3-D printing process used in their fabrication. First, we develop a lossy unit-cell analysis based on the finite element method to predict the effective attenuation of the metamaterial. We analyze factors such as unit cell size and geometry and viscoelastic losses in the base material to determine their influence on the metamaterial’s frequency-dependent attenuation. Then, we experimentally characterize the attenuation of multiple metamaterial realizations using the through-transmission method within a frequency range of 0.5–5 MHz. Comparing the numerical predictions to experimental results reveals the influence of practical 3-D-printing process parameters on attenuation. The results establish a framework for evaluating and optimizing attenuation behavior in ultrasonic metamaterials, accelerating their adoption in practical ultrasonic applications, including imaging and therapeutic ultrasound, and non-destructive testing.