FEKO Tutorial 2 - Page 2 (Preparing for the FEKO solver)
On the previous page, we have created all the geometry we need. On this page, we'll set the solution parameters for FEKO,
and set some special solver methods that will give us better run-times and properties.|
Before meshing, we want to union all of these components into one structure, so that the mesh points will all line up (the feed wire must lie on the vertex of a triangle in the cylinder mesh for the MoM technique to work properly). Select all three objects (Blade, Cylinder1, Feed) by clicking each while holding the control key, and then click the “union parts” button:
You have now created a single object composed of the 3 parts, the default name is "Union1".
Set the frequency to 300 MHz, add a port and a voltage source to the wire as in the first FEKO tutorial. Request S-parameters and the 3D far field as before. Your screen should resemble that shown below:
Mesh as before. Remember to hit “suggest” to determine the edge lengths and segment lengths for this frequency.
Now, the default solver on FEKO is Method of moments. A more advanced, equally accurate but much faster method is to set the solver to the Multi-Level Fast Multipole Method. This can be done easily by clicking Solution->Solution Settings:
Then click the MLFMM tab, and click “Solve model with the MLFMM”. Then click OK.
MLFMM uses significantly less memory than MoM, as well as having a much faster solution time. Both of these properties will be required for handling objects that are several wavelengths or more in size.
For metallic objects that define an enclosed volume with all normals pointed outward (such as a cylinder or sphere, but not a blade), we can get better (quicker, more accurate) solutions from FEKO if we set some properties to the mesh associated with these objects. In the region below the CADFEKO tree, there is a tab for “Faces”:
Select the three faces that correspond to the cylinder (the fourth surface is the blade, do not click that). You can tell which surfaces are selected because they change color in CADFEKO.
Right click on the highlighted faces in the faces tree and select properties:
Then, under the solution tab in the window that pops up, select “combined field” for integral equation. This should always be done for objects that enclose a volume with all normals pointed outward. See the FEKO users manual for more information.
Now save your file and we have created our model with CADFEKO.
We could run our model directly here using Run->FEKO. However, I'll take this opportunity to introduce EDITFEKO, which can be a powerful tool for editing how FEKO solves your model.