Acoustic application 1 Acoustics 1 Audio systems 1 Bandwidth 1 Double flexural structure 1 Economic and social effects 1 Electrode configurations 1 Electrodes 1 Equipment Design 1 Experimental methods 1 Fluidic backing layer Fluidics 1 Frequency band width 1 In-plane polarization 1 Membranes 1 Piezoelectric membranes 1 Piezoelectric micromachined ultrasonic transducer (PMUT) 1 Piezoelectricity 1 Printed circuit board 1 Resonance frequencies 1 Transducers 1 Ultrasonic transducers 1 Ultrasonics 1 Underwater acoustic communication 1 Wide-band high-sensitivity underwater acoustic transducer 1 acoustics 1 electrode 1 equipment design 1 transducer 1 ultrasound 1