Title: Application of Piezoelectric Ceramics in Communication
system Dr. & Prof. Chun-Huy Wang Electronical Engineering,
Nan-Jeon Institute of Technology Multimedia English Teaching
PP.
Piezoelectricity Mechanical and electrical energy conversion
phenomena, discovered by France Scientist Pierre and Jacques Curie
brother in 1880. Direct Piezoelectric Effect Mechanical Electrical
Converse Piezoelectric Effect
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Piezoelectricity
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Piezoelectric Ceramics (perovskite) Pervoskite structure, with
the chemical formula as ABO 3 e.g. : BaTiO 3 cornal center face
center
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Piezoelectric Ceramics cornal center face center
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Domain and domain boundaries of polycrystalline BaTiO 3 -(Jaffe
et al. 1971), (left)domain structure of unpoled ferroelectric
ceramics (right) graphical representation
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Poling Poling is the final process in the fabrication.
Initially, unpoled ceramics have no piezoelectricity because the
piezoelectric tensors of the grains are randomly oriented. During
the poling process, ferroelectric switching occurs and creates non
zero overall piezoelectric tensors.
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(3) after poling (1) unpoled (2) during poling
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P~E Curve Domain Wall Movement
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P~E curve vs Voltage Applied
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Communication Applications Piezoelectric ceramics used as the
resonator and filter in communication system with frequency lower
than 100MHz For frequency higher than 100MHz the Surface Acoustic
Wave (SAW) devices is used.
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Communication Applications The ceramic filter and resonator are
made of high stability piezoelectric ceramics that functions as a
mechanical resonator. The frequency is primary adjusted by the size
and thickness of the ceramic element. Typical application includes
TVs, VCRs, telephones, remote controls and radios.
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Communication Applications
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Operating Principle and feature of each filter
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Ceramics Resonator Resonator is the basic frequency control
component, the piezoelectric filter is composed by the
piezoelectric resonator.
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Ceramics Resonator
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Ceramic Filter Monolithic Filter (used for low frequency)
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Ceramic Filter
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SAW Resonator and Filter SAW : Surface Acoustic Wave In natural
world, SAW can create by earthquake. In engineering, SAW can create
by piezoelectric effect.
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SAW Resonator and Filter
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Advantages of SAW High Sensitivity High Accuracy Passive
Wireless Digitalized Mass Production Many Application
Possibilities
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SAW Resonator and Filter Two Port ResonatorOne Port
Resonator
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SAW Resonator and Filter Applications of SAW Filter GSM
Applications of SAW Filter PCS & CDMA
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SAW Resonator and Filter Applications of SAW Resonator