Characterization and Modelling of Circular Piezoelectric Micro Speakers for Audio Acoustic Actuation

Abstract

A study of circular piezoelectric micro speakers is presented for applications in the audio frequency range, including values for impedance, admittance, noise figures, transducer gain, and acoustic frequency responses. The micro speakers were modelled based on piezoelectric micro ultrasonic transducer (pMUT) design techniques and principles. In order to reach the audio frequency range, transducer radii were increased to the order of one centimetre, whilst piezoelectric layer thicknesses ranged the order of several μm. The micro actuators presented might be used for a variety of electroacoustic applications including noise control, hearing aids, earphones, sonar, and medical diagnostic ultrasound. This work main contribution is the characterization of the design space and transducer performance as a function of transducer radius, piezoelectric layer thickness, and frequency range, looking towards an optimized fabrication process.

A study on (K, Na) NbO3based multilayer piezoelectric ceramics micro speaker

“…However, the traditional moving coil speakers have a complex structure and are difficult to miniaturize. The magnetic radiation and the coupling interactions between the voice coil and magnet also limit their applications [3]. By contrast, piezoelectric micro speakers with a simple sandwich structure [2] are easy to miniaturize, and the direct electro-mechanical transformation eliminates the effects of magnetic fields.…”

MEMS audio speakers *

“…• Dimensions: Radius ranges from 0.75 mm to 1.25 cm, and thickness from 10 µm to 0.5 mm • dB SPL @ f kHz: -• Measurement distance: -• Actuation voltage: -Reproduced from[39]. CC BY 4.0.• Dimensions: Graphene electrode with area 12 × 7 cm 2 , thickness is only 1.36 nm for 4 layers whereas other metal electrodes are usually more than 100 nm thick • dB SPL @ f kHz: 40 dBSPL @ 1 kHz • Measurement distance: 10 cm • Actuation voltage: -Reprinted from[40], with the permission of AIP Publishing.…”

Piezoelectric Unimorphs Dynamic Response Measurement

“…They have a wide range of applications as actuators or sensing elements and are commonly utilized in micropumps [1], flow control actuators [2] or energy harvesting systems [3]. The main application field is represented by speakers and buzzers in acoustical systems [4], [5] at working frequency of 100 Hz to 10 kHz.…”