Broadband ultrathin acoustic wave diffusion structure

A broadband ultrathin acoustic wave diffusion structure, comprising a plurality of acoustic wave diffusion units, wherein each acoustic wave diffusion unit comprises at least one acoustic wave propagation section, and an acoustic wave focused section communicating with the acoustic wave propagation section is arranged according to needs;

• the acoustic wave focused section is formed by an acoustic wave focused cavity filled with acoustic material;
• the acoustic wave focused cavity is a variable-section cavity, and isotropic or anisotropic acoustic material is filled in the variable-section cavity;
• the acoustic wave propagation section is formed by a simply connected acoustic wave propagation passage with a close end;
• and
• in different acoustic wave diffusion units, the simply connected acoustic wave propagation passages have different lengths;
• some acoustic wave diffusion units have no acoustic wave focused section, and only comprise the acoustic wave propagation sections;
• some acoustic wave diffusion units comprise acoustic wave focused sections and acoustic wave propagation sections, and the acoustic wave focused cavities of the acoustic wave focused sections communicate with the simply connected acoustic wave propagation passages of the acoustic wave propagation sections;
• for the acoustic wave diffusion unit comprising the acoustic wave focused section and the acoustic wave propagation section, the simply connected acoustic wave propagation passage of the acoustic wave propagation section is closely arranged through the measures of circuitry, bending, coiling or stacking in a monolayer or multilayer or spatial spiral structural form, and occupies part or whole of available space of the broadband ultrathin acoustic wave diffusion structure.