Magnitude and phase reciprocity calibration of ultrasonic piezoelectric disk in air

TL;DR

This paper presents a modified reciprocity calibration method for ultrasonic piezoelectric disks in air, measuring their magnitude and phase responses with finite element support, aiming for improved transducer characterization.

Contribution

It introduces a modified three-transducer reciprocity calibration technique supported by finite element simulations for ultrasonic transducer characterization in air.

Findings

Magnitude and phase responses can be measured with fair accuracy around the first radial mode.

Finite element simulations support and validate the measurement process.

Further work is needed to quantify calibration accuracy and extend frequency range.

Abstract

A modified conventional three-transducer reciprocity calibration method is used to measure the magnitude and phase responses of the transmitting voltage response and the free-field open-circuit receiving voltage sensitivity of ultrasonic piezoelectric transducers radiating in air at 1 atm. The transducers used in this work are 20 x 2 mm circular piezoelectric ceramic disks with their first and second radial modes at approximately 100 and 250 kHz, respectively. The transducer characterization is supported and aided by finite element simulations of the measurement system and the measured frequency responses. Preliminary results indicate that the magnitude and phase responses of the transmitting voltage response and the free-field open-circuit receiving voltage sensitivity can be measured with fair accuracy in a limited frequency band around the first radial mode of the piezoelectric ceramic disk. Further work is needed to demonstrate and quantify the accuracy actually obtained using the three-transducer reciprocity calibration method, to achieve transducer characterization at a calibration accuracy level, and to achieve calibration above the calibrated frequency range of the B&K 4138 microphone.