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Theses

Transducteurs à domaines ferroélectriques alternés pour composants à ondes de surface appliqués au traitement du signal radio-fréquence par composants passifs

Abstract : For about twenty years, mobile telephony has been booming. This mode of communication requires the use of radio frequency (RF) filters able to select the useful signal during reception and emission. Mobile phone miniaturization has needed the development of new filters based on the use of acoustic waves, especially surface acoustic wave (SAW). In order to meet the challenges of modern RF filters for cellphones (frequency increase, higher emission power, size reduction), a new kind of transducers based on the use of alternating ferroelectric domains has been considered. In fact, ferroelectric materials such as lithium niobate (LiNbO3) show a spontaneous polarization which can be reversed. In this way, the classical interdigital transducers (IDTs) usually used in the surface acoustic wave devices can thus be replaced by periodically poled transducers (PPTs). The aim of this thesis is to validate the principle of this new kind of transducers and to prove that it is possible to fabricate filters using such periodically poled transducers. A theoretical study using a simulation tool combining finite element and boundary element analyses has been performed and the design and fabrication of those devices are presented. Periodically poled structures have been proved to be operationnal, that is why several objects exploiting this principle have been designed and manufactured (acoustic waveguides, electro-optical devices and isolated wave resonators).
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https://tel.archives-ouvertes.fr/tel-00447117
Contributor : Emilie Courjon <>
Submitted on : Thursday, January 14, 2010 - 12:11:39 PM
Last modification on : Thursday, November 12, 2020 - 9:42:06 AM
Long-term archiving on: : Thursday, June 17, 2010 - 8:40:38 PM

Identifiers

  • HAL Id : tel-00447117, version 1

Citation

E. Courjon. Transducteurs à domaines ferroélectriques alternés pour composants à ondes de surface appliqués au traitement du signal radio-fréquence par composants passifs. Acoustique [physics.class-ph]. Université de Franche-Comté, 2009. Français. ⟨tel-00447117⟩

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