Phononic structures and acoustic band gaps based on either bulk or thin materials have been researched in length in the past decades. However, few investigations have been performed on phononic structures in thin plates to form acoustic wave band gaps by using ultrasonic transducers. Besides, The measurement is based on line-focus P(VDF-TrFE) transducers that have been used successfully to measure lamb wave dispersion velocities and surface acoustic wave velocities for both isotropic and anisotropic bulk materials. In this study, we made a lot of phononic plates as sample and the transducer has been further applied to phononic crystals manufactured by patterning periodical holes both square array and hexagonal array, different diameter, different lattice distance and different wave propagation direction for those thin plates with same 50 µm thickness. In order to obtain the Lamb wave spectrum we measured using V(f,z) measurement system, then using double fourier transform as waveform processing method. Experimentally, P(VDF-TrFE) line-focus transducers and V(f,z) measurement system has been successfully obtained lamb wave spectrum image with band-gaps phenomena during V(f,z) measurement on the phononic plates. Finally, this experimentally claimed that our P(VDF-TrFE) line-focus transducers and V(f,z) measurement system is an alternative experimental set up for observing band-gap phenomena which is easier to build, easier to made and easier to perform compared with Laser Ultrasound or SAW device.

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