Design and analysis of an acoustic demultiplexer exploiting negative density, negative bulk modulus and extra-ordinary transmission of membrane-based acoustic metamaterial

A typical membrane-based acoustic metamaterial has been reconfigured into an array of semi-flexi-walled membrane-based Helmholtz resonators to design a novel 4 port device which demultiplexes an incoming broadband acoustic signal into frequency ranges where negative modulus, density and extra-ordinary transmission behaviour exist. It has two ports exhibiting identical transfer functions and for input given in any of these ports, the device operates as a 3 port demultiplexer. The device is asymmetric in its functionality both in its degree of demultiplexing and bandwidths of the demultiplexed spectrum. Theoretical analysis of this acoustic demux is carried out by modelling it as a combination of two independent physical systems and is further validated by full-wave analysis.