Figure 3
From: Sound Pressure Level Gain in an Acoustic Metamaterial Cavity
Independent control of refractive index and impedance:
(a) three different corrugated structures used to produce identical path lengths of l = 4.6 cm but varying heights, h; (b) effective refractive indices and impedances of the three different structures shown in (a) calculated using acoustic numerical retrieval scattering method; (c) SPL inside the subwavelength cavity for three different metamaterial structures; (d) three different structures with identical heights, h, but varying path widths, w; (e) effective refractive indices and impedances of the three different structures shown in (d); (f) acoustic pressure inside the cavity for three different metamaterial structures.
