Design and Optimization of Omnidirectional Band Gap for One-Dimensional Periodic and Quasiperiodic Phononic Heterostructures

A new kind of one-dimensional multilayer phononic heterostructure is constructed to obtain a broad acoustic omnidirectional reflection(ODR) band.The heterostructure is formed by combining finite periodic phononic crystals(PnCs) and Fibonacci(or Thue-Morse) quasiperiodic PnCs.From the numerical results performed by the transfer matrix method,it is found that the ODR bands can be enlarged obviously by using the combination of periodic and quasi-periodic PnCs.Moreover,an application of particle swarm optimization in designing and optimizing acoustic ODR bands is reported.With regards to different thickness ratios and periodic numbers in the heterostructure,we give some optimization examples and finally achieve phononic heterostructure with a very broad ODR bandwidth.The result provides a new approach to achieve broad acoustic ODR bandwidth,and will be applied in design of omnidirectional acoustic mirrors.