Figure 2: Photograph of the fabricated unit cell.
From: Non-reciprocal and highly nonlinear active acoustic metamaterials
Left: the front side of the cell shows the three terminals of the PZM, and the Helmholtz cavity tuned on 1,500 Hz; right: the back side of the cell shows the Helmholtz cavity tuned on 3,000 Hz. The PZM is completely covered by the brass ground plane.
