EXPERIMENTAL FULL BAND-GAP OF A SONIC-CRYSTAL SLAB MADE OF A 2D LATTICE OF ALUMINUM RODS IN AIR

We present here experimentally obtained band-gap characteristics of a sonic-crystal slab composed of a two-dimensional square-array of aluminum rods in air, which is constructed between a pair of parallel metallic sheets with a spacing smaller than the wavelength. We observed a full band-gap, that is a band-gap common to the [100] and [110] directions of plane-wave propagation, between 14.1 kHz and 18.7 kHz, in the normalized frequency between 0.49 and 0.65, with a transmission ratio smaller than −30 dB using a tone-burst technique. These results agree well with the numerical ones. The realization of a full band-gap in the soniccrystal slabs indicates a further development to various shapes of sonic wave-guides and sonic circuit including directional couplers, ring resonators, filters and splitters.

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