Broadband 1-3 Piezoelectric Composite Transducer Design Using Sierpinski Gasket Fractal Geometry.

Area of Science:

• Materials Science
• Acoustics
• Biomimetics

Background:

• Wider operational bandwidth is crucial for ultrasound transducer applications.
• Nature-inspired designs, like those in hearing organs, exhibit broad bandwidths.
• Conventional 1-3 piezoelectric composites offer wider bandwidths than ceramic counterparts.

Purpose of the Study:

• To explore the potential of fractal geometry, specifically the Sierpinski Gasket (SG), for extending ultrasound transducer bandwidth and sensitivity.
• To compare the performance of an SG fractal 1-3 piezocomposite with conventional designs.

Main Methods:

• Finite-element analysis (FEA) for theoretical comparison.
• Experimental fabrication and characterization of a 580-kHz single-element transducer.
• Performance evaluation using transmit voltage response and open-circuit voltage response.

Main Results:

• The SG fractal design demonstrated a 27.2% bandwidth improvement and 3.8 dB sensitivity enhancement over conventional 1-3 composites in transmission mode.
• Compared to a commercial transducer, the SG fractal design achieved up to 105.1% bandwidth improvement in transmission.
• In reception mode, the SG fractal design showed 2.5% and 32.9% bandwidth improvement over conventional and commercial transducers, respectively.

Conclusions:

• The Sierpinski Gasket fractal geometry offers a promising approach to significantly enhance the operational bandwidth and sensitivity of ultrasound transducers.
• This novel design outperforms both conventional 1-3 piezoelectric composites and existing commercial ultrasound transducers.