Title: Application of Piezoelectric Ceramics in Communication systemDr. & Prof. Chun-Huy Wang

Electronical Engineering, Nan-Jeon Institute of TechnologyMultimedia English Teaching PP.

Electronic Ceramics Dielectric Property

Piezoelectricity

Pyroelectricity

Ferroelectricity

What can piezoelectric ceramics do?

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

Piezoelectricity

Piezoelectric Ceramics(perovskite)Pervoskite structure, with the chemical formula as ABO3 e.g. : BaTiO3 cornalcenter face center

Piezoelectric Ceramicscornalcenter face center

Domain and domain boundaries of polycrystalline BaTiO3 -(Jaffe et al. 1971),

(left)domain structure of unpoled ferroelectric ceramics (right) graphical representation

PolingPoling 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.

(3) after poling(1) unpoled(2) during poling

P~E CurveDomain Wall Movement

P~E curve vs Voltage Applied

Communication ApplicationsPiezoelectric ceramics used as the resonator and filter in communication system with frequency lower than 100MHzFor frequency higher than 100MHzthe Surface Acoustic Wave (SAW) devices is used.

Communication ApplicationsThe 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.

Communication Applications

Operating Principle and feature of each filter

Ceramics ResonatorResonator is the basic frequency control component, the piezoelectric filter is composed by the piezoelectric resonator .

Ceramics Resonator

Ceramic FilterMonolithic Filter (used for low frequency)

Ceramic Filter

SAW Resonator and Filter SAW : Surface Acoustic WaveIn natural world, SAW can create by earthquake.In engineering, SAW can create by piezoelectric effect.

SAW Resonator and Filter

SAW Resonator and FilterAdvantages of SAW High Sensitivity High Accuracy Passive Wireless Digitalized Mass Production Many Application Possibilities

SAW Resonator and FilterTwo Port ResonatorOne Port Resonator

SAW Resonator and FilterApplications of SAW Filter GSMApplications of SAW Filter PCS & CDMA

SAW Resonator and FilterApplications of SAW Resonator

Thank youFor Listening