Designing a tunable acoustic resonator based on defect modes, stimulated by selectively biased PZT rods in a 2D phononic crystal.
Ultrasonics
; 92: 8-12, 2019 Feb.
Article
em En
| MEDLINE
| ID: mdl-30216782
ABSTRACT
Reconfigurable phononic crystals (PnCs) and related devices are highly attractive because of their flexibility for different applications. We present the design procedure for a tunable acoustic resonator based on a 2D PnC, consisting of a periodic array of piezoelectric rods of radii 175⯵m as inclusions arranged in air background. A single point defect devised by a rod of radius 161⯵m, replacing one of the inclusions, plays the role of the acoustic resonator, leading to a defect frequency in the phononic band gap (fdâ¯≈â¯432â¯kHz). Applying a â¼1% strain to the defect rod, via an external voltage, tunes the defect resonant frequency within the phononic band gap. It is shown that the maximum tunability and the frequency shift depends on the defect size, and is achieved about Δfdâ¯=â¯440â¯Hz for the defect with the expense of descending quality factor. Considering the pattern of the localized pressure field, we introduce a multi-defect structure with five symmetric defect rods, corresponding to the maxima of field distribution. It is shown that maximum frequency shift of the dominant defect frequency is achieved about Δfdâ¯=â¯1.14â¯kHz for defect radius of 161⯵m, when all five defect rods are strained. The proposed tunable filter based on multi-defect structure results in an enhancement of about 2.6 times in the maximum frequency shift, in comparison with the single defect structure, and introduces a promising approach for realizing tunable acoustic devices.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Idioma:
En
Revista:
Ultrasonics
Ano de publicação:
2019
Tipo de documento:
Article
País de afiliação:
Irã