Rayleigh-Bloch mode based monolayer bend waveguide

Abstract

A monolayer bend waveguide is designed based on the features of Rayleigh-Bloch (RB) mode wave in one-dimensional diffraction grating. The feasibility that the RB mode wave can transmit along the bend waveguide is demonstrated by the time-domain and frequency-domain finite element method, respectively. The results show that two different modes of transmission wave exist because of employing the circled unit cells. They possess different acoustical energy localization positions. In mode-1, the energy is localized between unit cells. In mode-2, the energy is localized in the center of unit cell, therefore, acoustic wave transmits with nearly no loss. Modulated sinusoidal wave and Gaussian pulse wave are used in the time-domain investigation. Because only RB mode waves can transmit and different modes have different energy distributions, the bend waveguide acts as an acoustic filter for the broadband waves. This study is conducive to the acoustic wave directional transmission, acoustic signal detection and identification.