Modal displacement of a TC SAW at series resonance
Model Description
This simple unit cell model of a single port Temperature Compensated (TC) Surface Acoustic Wave (SAW) filter allows rapid simulation of device performance. This allows a very wide range of designs to be explored before moving to more complex full 3D simulations.
The model comprises a pair aluminium electrodes on a piezoelectric substrate. Above the electrodes a layer of SiO2 is used for temperature compensation. The substrate can either be Lithium Tantalate (LiTaO3) or Lithium Niobate (LiNbO3). The model is set up to simulate a Y-cut, which can be rotated to the desired angle. The base design generates an SH mode at 1.5 GHz using a finger pitch of 1.3 µm.
Model Geometry, with SiO2 TC layer highlighted
Design Variables
The base model allows the following design variables to be adjusted. By default electrode thickness and SiO2 thickness are set as design variables to be swept (indicated by *).
|
Parametric Variable |
Description |
Default Value |
|---|---|---|
|
subs_thk |
Thickness of substrate |
7.5 µm |
|
elec_thk* |
Thickness of the electrodes |
200 nm |
|
si02_thk* |
Thickness of Si02 layer |
350nm |
|
fin_pitch |
SAW finger pitch |
1.3 µm |
|
aratio |
Electrode aspect ratio |
0.5 |
|
nfing |
Number of finger pairs |
100 |
|
fin_len |
Finger length |
50 µm |
|
piezo_mat |
Piezo material |
lt |
|
cut_ang |
Y-cut angle |
42 |
Outputs
A wide range of outputs can be generated, including:
- Electrical Impedance / admittance
- S parameters
- Mode Shapes (Harmonic Analysis)
- Energy flow analysis
Typical outputs, Impedance (top) mode shape (bottom)
Runtime Statistics
|
Degrees of Freedom |
6426 |
|
Solve Time |
74 secs (8 CPUS) |
|
Core Hours |
0.16 |
|
Memory Usage |
75 MB |
Files
The following input files are required to run this model, click here to download the input files:
Design Studies
The following example design studies were carried out using this model: