Figure 1. Characteristic oscillations of acoustic atoms and the decoupling of constitutive wave parameters.

(a) Linear and radial characteristic oscillations of acoustic atoms for ρ and B⁻¹, respectively. (b) Schematic of the proposed meta-atom. blue and red: outer and inner membranes; black: solid wall; t_O(I): outer (inner) membrane thickness; s_O (shaded in light blue) and s_I (shaded in light red): outer and inner area (region) in the meta-atom unit cell.