Afterwards, open the Special Mesh Properties dialog box by pressing the Specials button. Please activate the Surface: General tab and reduce the Curvature refinement ratio to 0.03 and increase the Maximal number of steps from curvature refinement to 1000 to allow a better starting approximation of the circular elements. Press the Help button to obtain more information on the settings.
Please check the settings and confirm them by clicking the OK buttons in both dialog boxes.
? Frequency Domain Solver Settings
The Frequency Domain Solver Parameters dialog box is opened by selecting Solve Frequency Domain Solver from the main menu or by pressing the corresponding icon toolbar.
in the
There are three different methods to choose from. For the example here, please choose the General Purpose frequency domain solver. In the Mesh Type combo box you may choose between Hexahedral and Tetrahedral Mesh. Due to the previously made settings in the Mesh Properties dialog box, the Tetrahedral Mesh is already selected.
S-parameters in the frequency domain are obtained by solving the field problem at different frequency samples. These single S-parameter values are then used by the broadband frequency sweep to get the continuous S-parameter values. With the default settings in the Frequency samples frame, the number and position of the frequency samples are chosen automatically in order to fit the required accuracy limit throughout the entire frequency band.
Unlike the time domain solver, the tetrahedral frequency domain solver should always be used with the Adaptive tetrahedral mesh refinement. Otherwise, the initial mesh may lead to a poor accuracy. Therefore, the corresponding check box is activated by default.
Please note that it is necessary to choose a suitable Adaptation Frequency, correspondent to the assumed radiation behavior of the antenna. A good choice for an antenna structure is usually the center frequency of the calculation range, so in this example we enter the value of 2.5 GHz in the dialog box (see picture above) and deactivate the corresponding check box. Furthermore, to ensure that the adaptation will satisfy the desired accuracy limit, we increase the Maximum number of passes to 20 in the Adaptive Tetrahedral Mesh Refinement dialog box by pressing the Properties button of the mesh refinement:
After confirming this setting with the OK button, everything is now ready; you may press Start to start the calculation. A progress bar and abort button appear in the status bar, displaying some information about the solver stages:
After the desired accuracy for the S-parameter has been reached, the simulation stops. When the simulation has finished or has been aborted, both items disappear again. During the simulation, the Message Window will display details about the performed simulation.
Frequency Domain Solver Results
Congratulations, you have simulated the patch antenna using the general purpose tetrahedral frequency domain solver! Lets review the results.
? 1D Results (S-Parameters)
You can visualize the maximum difference of the S-parameters for two subsequent passes by selecting 1D Results
Adaptive Meshing
Delta S from the navigation tree:
As evident from the above diagram, several passes of the mesh refinement were required to obtain highly accurate results within the given accuracy level that is set to 1% by default.
You can view the S-parameters magnitude in dB by selecting 1D Results navigation tree:
|S| db in the
It is possible to precisely determine the operational frequency for the patch antenna. Activate the axis marker by pressing the right mouse button within the main window and selecting the Show axis marker option from the context menu. Now you can move the marker to the S11 minimum and pinpoint a resonance frequency for the patch antenna of about 2.4 GHz.