AT – Cut Quartz crystal operating in Thickness Shear Mode (For QCM – Quartz Crystal Monitor Applications)

What is AT – Cut Quartz?

• AT – Cut Quartz means Y is the cut direction (thickness direction)and X is the wave propagation direction.

• In AT – Cut Quartz, the Y – axis is rotated by 35°21´• Therefore to obtain correct crystal orientation, one needs to get

back to the definition of this crystal cut. • AT – Cut Quartz is represented as yxl 35°21´

– which means “yx” is the initial position of the crystal, where• the first letter “y” is the thickness direction

• the second letter “x” is the length direction.

• the third letter “l” indicates the axis of rotation (l = length). In this case, “x” is the axis of rotation.

– For this configuration, the vibration mode is thickness-shear.

Ref: John Buchanan, Handbook of Piezoelectric Crystals for Radio Equipment Designers, 1965.

Physics Selection

Geometry

Global Coordinate System (Default Setting)

Define a Local Coordinate System

X

Z

Y

X

Z

Y

Rotation about x-axis

Visualization of Local Coordinate System

Global Coordinate System Local Coordinate System

Subdomain Settings

Local coordinate system named “Coordinate system 1” is used to get the correct crystal orientation for AT – Cut Quartz.

Boundary Settings

Integration Coupling Variable

Meshing

Click on Mesh Selected

Solver Parameters

range(4e6,0.3e6,4.9e6) range(4900000,300000/79,5200000) range(5200000,300000,6100000)

Results

Plot of total displacement at resonant frequency of 5.093MHz

Results

Results