Stopping and filtering waves in phononic circuits

The acoustic band structures and transmissions through a one-dimensional (I D) monomode waveguide made of asymmetric slender tube loops pasted together with slender tubes of finite length are investigated theoretically. These monomode circuits may exhibit large stop bands where the propagation of acoustic waves is forbidden. These stop bands (gaps) originate both from the periodicity of the system and the resonant modes of the loops. The width of these bandgaps depends on the geometrical parameters of the structure and may be drastically increased in a tandem geometry made of several successive asymmetric serial loop structures (ASLSs) which differ in their geometrical characteristics. These ASLSs may have potential applications as ultra-wideband filters.