[Seminar] Tunability of electrically controlled piezoelectric phononic crystals - Archive ouverte HAL
Autre Publication Scientifique Année : 2022

[Seminar] Tunability of electrically controlled piezoelectric phononic crystals

Résumé

Phononic Crystals (PCs) (i.e. periodic arrangements of several materials) have received a great deal of interest for the last two decades because of the unusual properties that they can exhibit. Classically, depending on material properties and geometrical arrangement, PCs can produce band gaps, i.e. frequency ranges where the propagation of waves is forbidden (i.e. waves are evanescent). These Bragg band gaps offer several potential applications such as sonic insulators or filters, from the kHz to the GHz range depending upon the spatial periodicity. In this presentation, the general case of PCs made of piezoelectric materials is studied where the band gaps may be tuned by changing the electrical boundary conditions. First, a stack of piezoelectric rods, poled along their thickness is considered [S. Degraeve et al, J. Appl. Phys. 115, 194508 (2014)]. This device exhibits Bragg gaps that depend on the electrical boundary conditions chosen on periodically placed electrodes. An analytical model is developed that is compared to finite element results, validating the model. Depending on the electrical boundary condition, tunability is clearly demonstrated, i.e. an increase or a decrease of the width and the position of the stop bands. Ultrasonic experiments are presented, showing a good agreement with the theoretical predictions. Then, more complex control involving space-time modulation of electrical boundary conditions give access to tuning/control of nonlinear physical effects such as non reciprocity [C. Croenne et al, Appl. Phys. Lett. 110(6), 061901 (2017)]. The second part of this presentation concerns the extension of this concept to surface acoustic waves (SAW). In fact, SAW devices are constituted of piezoelectric phononic crystals due to the periodicity of the metallization patterns. We have shown that their working frequencies can be modified by a change of the electrical conditions on the electrodes that constitute the mirrors of a single-port SAW resonator. Numerical as well as experimental results are presented that underline a shift of the resonance frequency by a change of the electrical condition. It allows the development of new strategies for tunable components, compatible with RF microfabrication.
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Dates et versions

hal-03837016 , version 1 (02-11-2022)

Identifiants

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Anne-Christine Hladky. [Seminar] Tunability of electrically controlled piezoelectric phononic crystals. MetaMAT Weekly Seminars, 2022, ⟨10.52843/meta-mat.v3p896⟩. ⟨hal-03837016⟩
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