Abstract: We establish a periodical obstacle with 1D grating as an acoustic model and simulate with Comsol Muhiphysics. The acoustic wave propagating though obstacle during a long period of wavelength is also discussed. We change the parameters of the obstacles and have some comparison with the acoustic field and transmission. A- nalysis of the sound wave propagation and transmission characteristics with theory are performed. We compare and analyze the transmission calculated by Comsol Multiphysics to illustrate the origin of the acoustic transmission peaks and the abnormal phenomenon of transmission.

Key words: 1 D grating, transmission, standing wave, FP resonance