This full 3D SAW filter model provides a complete picture of device performance. By simulating the device in full 3D a range of parasitic effects can be considered to avoid carrying undesirable performance into production. In this example, you will be shown how to get the impedance and a mode shape from a 3D SAW filter created using the symbol language.
What is symbol?: Check out these articles to get more familiar with OnScale's scripting language symbol.
The model comprises a pair of aluminum IDT electrodes on a piezoelectric substrate. These are terminated with a grating. 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.
Download and Open the Model
OnScale Input Files have the file extension *.flxinp. To open the downloaded file:
- Open OnScale
- Select Analyst Mode
- Select the Menu button in the top left of the application
- Select Open
Preview model is used to view the geometry dimensions and material assignment of a model to ensure the script is correct. To preview a model, select the Preview Model icon in the Home tab of the application ribbon.
Note: Preview model will display data from any grph commands that come before the prcs command. If you have more than one grph command, you can cycle through the graphics by continuously selecting Preview Model. To close the preview, select Stop Preview.
Run Model on Cloud
To run the model on the cloud, select the Run on Cloud button in the Home tab of the application and follow these steps:
- Click select and open the file you wish to run (saw_full_3D.flxinp)
- Select Estimate
- Select Run
- From the Home tab, select the Storage icon
- Select the Refresh icon to refresh storage
- Select the Job Name from the dropdown menu
- Select the Download button
- Select Download All
Choose a directory to download the results to. These results will be stored in the folder: saw_full_3D-YYYYMMDD-HHMMSS\1 where YYYYMMDD-HHMMSS is the current date and time.
Switch to Post Processor
Post Processor is a suite of tools used to visualise and analyse output data generated from OnScale simulations. Switch to Post Post Processor.
What kind of analysis can I do in Post Processor? Find out here.
We will now look at the impedance and mode shape of the model at 1.5 GHz:
- In File Explorer, navigate to the download directory and double click the file 'saw_full_3D.flxhst' to open it and 'saw_full_3D.flxdato' to load them in to Results Manager
- In Home tab of ribbon, select Configure viewport > 2_1
- Select top viewport by clicking inside of it
- In Results Manager, select the voltage time history 'pize top:Voltage' by left clicking it
- From the Home tab of the ribbon, select the Impedance icon to calculate impedance
- In the Frequency History section of the Results Manager, double click 'Impd:top.amp' to plot impedance amplitude
- In Plot Controls, tick Log yAxis
- In Plot Controls, set xAxis Minimum to 1.1e9
- In Plot Controls, set xAxis Maximum to 2.2e9
- In Plot Controls, set yAxis Minimum to 1
- In Plot Controls, set yAxis Maximumto 1e3
- Select bottom viewport by clicking inside of it
- In Results Manager, double click ydsp
Learn how to get S-Parameters from a Two-Port SAW
Take a look at our TC-SAW Example