LAUSR

Abstract In this paper, we proposed multi resonant scatterers which is comprised of two coaxial resonant shells. Four conceivable scatterers which are combinations of two different types of resonant shells such as shell with slit and perforations are examined. We calculated the insertion loss of sonic crystal made with said scatterers via simulation first. It is shown that, with said scatterers, the resonance band of the outer shell shifts towards low frequencies, wherever, it moves towards high frequencies for the inner one without significant alternation in the first Bragg band. Using this phenomenon, the local resonance frequency of any given resonant shell can be reduced further. The key discovery of the research is that one extra bandgap with reasonable frequency bandwidth is detected in the direction of wave propagation due to dipolar resonance of the hollow cavity present within shells which also is observed experimentally.