|
LGS crystals blanks or blocks
|
|
X Direction
|
5~40mm
|
|
Y Direction
|
5~40mm
|
|
Z Direction
|
~80mm
|
|
Direction Precision
|
±20’
|
|
Langasite slices
|
|
Diameter
|
5~14mm
|
|
Frequency
|
2.7~21MHz
|
|
Direction Precision
|
±20’
|
|
Surface Roughness(Lapped)
|
Ra=0.3~0.5μm
|
|
Sensor, SAW Wafers
|
|
Diameter
|
6~76.2mm
|
|
Thickness
|
0.13~0.5mm
|
|
Reference Flat
|
2~15MM
|
|
Surface Roughness (CMP single or double sides)
|
Ra≤1nm
|
|
Qrientation
|
Following customer specifications
|
Inches boules and CMP wafers.
Langasite crystal possesses some great properties, such as higher electromechanical coupling factor than quartz, no phase transition from room temperature to melt point. Some properties of langgasite crystal are shown in Table 1.
Table 1 Dielectric, elastic stiffness constants and their first order temperature coefficients of langasite crystal
|
Constant
|
Relative Dielectric Constant
|
Piezoelectric Constant (pC/N)
|
Elastic Stiffness (1011Pa)
|
|
ε11
|
ε33
|
d11
|
d14
|
c11
|
c12
|
c13
|
c14
|
c33
|
c44
|
|
Value
|
18.96
|
50.19
|
5.66
|
-5.48
|
1.898
|
1.058
|
1.022
|
0.144
|
2.626
|
0.535
|
|
First Order Temp.Coef. (10-6.K-1)
|
150
|
-760
|
329
|
-342
|
-66
|
204
|
-75
|
-335
|
-94
|
-63
|
Table 2 Comparative properties of piezoelectric crystals
|
PropertiesCrystal
|
Quartz SiO2
|
Langasite
La3Ga5SiO14
|
Lithium tetraborate Li2B4O7
|
Lithium tantalite LiTa3
|
|
Electromechanical Coupling Factor K,%(BAW)
|
7.0
|
15.8
|
24.0
|
47.0
|
|
Frequency Spacing Δf,%
|
0.25
|
0.90
|
4.00
|
7.00
|
|
Q-Factor Q,x103
|
100
|
50
|
10
|
2
|
|
Temperature Frequency Coefficient TFC, x10-6/℃
|
0.5
|
1.6
|
6.0
|
4.0
|
With the rapid development of the communication technology, the new generation communication system enables people not only to talk, but also to transmit image, data and video. Langasite crystal possesses high SAW properties compared with quartz.which make it to be the most competitive material in this field. SAW preperties of langasite andquartz are listed in the Table 3.
Table 3 SAW properties of langasite and Quartz
|
PropertiesCrystal
|
Quartz(SiO2)
|
Langasite(La3Ga5SiO14)
|
|
Density,g/cm3
|
2.65
|
5.746
|
|
SAW Velocity Vef,m/s
|
(0º,132.75 º,0 º)3157
|
(0º,140 º,25 º)2756
|
|
Electromechanical coupling factor K2emc,%(SAW)
|
0.14
|
0.36
|
|
Second order temp.coef.
α2,x10-8/℃2
|
-3.2
|
-6.8
|
|
Temp. Coef. TTO, ℃
|
25
|
23
|
|
Dielectric Constant ε
|
4.92
|
27
|
|
Power flow angle Ф, º
|
0
|
0.5
|
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