The integration between XFdtd and Optenni Lab enables matching network synthesis for antenna design. After an unmatched antenna is simulated in XF's full wave solver, S-parameters, efficiency, and far zone radiation pattern data are passed to Optenni Lab where it synthesizes a matching network topology and component values.
Check XF Application Preferences
XF requires the location of Optenni Lab's executable in order to open Optenni Lab from the application's Results browser. XF can find and configure the executable automatically, or users can set the location manually by selecting Edit ❯ Application Preferences and working under the External Tools tab.
Set Up a Project
Optenni Lab uses S-parameter, efficiency, and far zone radiation pattern results from a finite-difference time-domain (FDTD) simulation to determine the desired matching network topology. In order to compute those results, all of the standard steps—such as adding geometry, defining materials, and specifying the grid—in XF's workflow must be completed.
Before creating a simulation, users must add a far zone sensor to the project in order to collect a far zone radiation pattern. This is done by right-clicking on Far Zone Sensors ❯ New Far Zone Sensor in the Project Tree. The Geometry tab must specify theta and phi angles that cover the full 3-D sphere. Additionally, the Enable Far Zone Sensor and Collect Steady State Data options must be checked under the Properties tab.
When creating a simulation, users should consider two of the window's tabs. S-parameters must be collected for each feed that will be matched in Optenni Lab. This is accomplished by checking the desired Active Feed(s) in the Setup S-parameters tab.
In order to synthesize the matching network in Optenni Lab based on either efficiency or far zone radiation pattern data, users must add Frequencies in the Frequencies of Interest tab. Three to five frequencies per band are generally sufficient, but more may be needed for wide bands. Radiation, system efficiency, and radiation pattern are available once steady-state data is collected.
Export to Optenni Lab
Users can export to Optenni Lab through the right-click menu of a 3-D far zone radiation pattern in XF's Results browser. The Optenni Export Options dialog allows users to open Optenni Lab and load the full S-parameter matrix, efficiencies, available powers, and other data that XF determines based on the far zone selection.
The S-parameters are written to an *.sNp Touchstone file, the input power for each port and filename for the complex far field data is written to an .xml file, and a binary far field file is written for each port. Users can save the files to a specified location for future post-processing.
This is compatible with Optenni Lab 4.3 and later. When XF detects an earlier version, it prompts users to specify either radiation or system efficiency.
Optenni Lab is automatically launched and populated with data when export to Optenni Lab is chosen in XF's results browser. The image shows Optenni Lab with XF's S-parameters and efficiency data in the project tree on the left side of the user interface. Matching network synthesis is performed in Optenni Lab through Analyze ❯ Matching Circuit Generation.