A nonlinear propagation model-based phase calibration technique for membrane hydrophones.

Area of Science:

• Acoustics
• Ultrasound Technology
• Metrology

Background:

• Accurate phase calibration of membrane hydrophones is crucial for quantitative ultrasound measurements.
• Existing methods often require specialized reference devices, limiting accessibility and increasing complexity.

Purpose of the Study:

• To develop and validate a new technique for phase calibration of membrane hydrophones up to 80 MHz.
• To enable accurate hydrophone characterization without relying on a separate phase reference device.

Main Methods:

• Utilized a nonlinear acoustic field generated by a 3.5 MHz focusing transducer.
• Employed a finite-difference model solving the nonlinear Khokhlov-Zabolotskaya-Kuznetsov (KZK) equation in the frequency domain for field prediction.
• Compared numerical simulations with far-field measurements from a bilaminar membrane hydrophone.

Main Results:

• Demonstrated negligible spatial averaging effects for the tested hydrophone at high drive levels.
• Achieved functional agreement between experimental results and a hydrophone response model.
• Validated the technique by measuring high-amplitude waveforms from a biomedical ultrasonic imaging system.

Conclusions:

• The proposed technique provides reliable phase calibration for membrane hydrophones up to 80 MHz.
• The method simplifies hydrophone calibration by eliminating the need for a phase reference device.
• Accurate deconvolution of the hydrophone's complex frequency response yields physically realistic ultrasonic waveform measurements.