Eight-channel acoustic demultiplexer based on solid-fluid phononic crystals with hollow cylinders

Abstract

We design a novel eight-channel demultiplexer in a solid-fluid phononic crystal structure. The basic structure has been formed by square arrangement of holes filled by water in tungsten background. These holes are embedded in background with filling fraction of 46 %. Generally, the proposed structure consists of nine type line defects for input and output channels. These line defects consist of two types of hollow cylinders. One of them is used in input channel and the other creates output channels. Input waveguide contains an L-branch waveguide which has been made by a row of hollow cylinders of water which is internally filled with tungsten. Each of output channels contains a row of hollow cylinders of Methyl Nonafluorobutyl Ether filled with tungsten. Hollow cylinders have different inner radii in each output waveguides. Hence, each output channels can transmit diverse narrow frequency passbands. We use the finite element method to determine the eigenfrequencies of structure. This structure can separate eight acoustic waves in frequency range between 166.6 kHz and 168.1 kHz. Separation of frequencies is accomplished with high quality factor and the width of frequency spectra between outputs are about 200 Hz. Crosstalk values of the proposed structure show that the eight-channel demultiplexer has efficient performance so that, the worst case of crosstalk value is equal to -26.68 dB.