Application of langasite crystals in monolithic filters operating in shear modes

“…There are 9 cation sites in which cations would be substituted by others, resulting in more than 100 langasite family materials that have been identified. [1][2][3] Besides LGS, La 3 Ta 0:5 Ga 5:5 O 14 (LTG) and La 3 Nb 0:5 Ga 5:5 O 14 (LNG) have been characterized for the IF filter of Wide-Code Division Multiple Access (W-CDMA) applications because of their high electromechanical coupling and zero-temperature coefficient of delay (TCD). [4][5][6][7][8][9][10][11][12] The LGS, LNG and LTG single crystals, however, have high melting points of 1400, 1450 and 1450 C, respectively.…”

Section: Introductionmentioning

confidence: 99%

Piezoelectric Properties of Ca₃NbGa₃Si₂O₁₄ Single Crystal

Karaki

Sato

Adachi

et al. 2004

Jpn. J. Appl. Phys.

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Langasite-type single crystal Ca3NbGa3Si2O14 (CNGS) was grown by the Czochralski technique. Dielectric, elastic and piezoelectric constants of CNGS were measured by the resonance-antiresonance method. At room temperature, dielectric constants ε11 T/ε0 and ε33 T/ε0 were 17.8 and 27.9, respectively. Electromechanical coupling coefficients k 12, k 25 and k 26 were also determined as 10.9, 17.3 and 11.9%, respectively. The measurements were carried out in a temperature range from -30 to 80°C. Temperature coefficients of the dielectric, elastic and piezoelectric constants were obtained. The line-focus-beam and plane-wave ultrasonic material characterization system was employed for measuring bulk acoustic velocities, and longitudinal and transverse wave velocities of 7408.4 m/s and 3136.2 m/s, respectively, in the c-direction uncoupled with piezoelectricity at 23°C were obtained. This was in good agreement with the results determined by the resonance-antiresonance method. The density of CNGS was 4125 kg/m3. All the parameters of the CNGS crystal for bulk and surface acoustic wave applications were determined in this research.

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“…The absence of the phase transformation between the melting point (e.g.1470 • C for LGS) and the room temperature makes these materials attractive for applications. These properties suggest the utilization of langasite materials for high temperature applications in BAW and SAW devices (Grouzinenko and Bezdelkin 1992;Ssakharov et al 1992).…”

Section: Crystals Of Cgg Group (Langasite Langanite Langataite)mentioning

confidence: 97%