HFSS - It is respecting the maximum tetraheda length specified? It seem not to be.

I've gone though the "UHF Probe" example in the HFSS manual, and have have noticed something odd. In the tutorial it says

"Far fields are calculated by integrating the fields on the radiatiuon surface. To obtain accurate far fields for antenna problems, the integration surface should be forced to have a lambda/6 to lambda/8 maximum tetrhedra length"


The tutorial tells one to set the maximum tetrahedra length to 3.5 inches, as that about lambda/6. So I done this by right clicking Mesh Operations -> Assign -> On Selection -> Lenght Based - see left of screen shot.

After I"ve run the analysis, I got the mess statistics from

HFSS -> Results -> Solution Data, clicking the Mesh Statistics tab.

What I notice is that the maximum edge length on "Air" (the radiation boundary), is 3.5281 inches, despite the fact I had specified the maximum should be 3.5 inches. I realise its not a lot more, but I'm surprised it is larger. Am I mis-interpreting the solution data in some way? Or is HFSS isgoring what I've set?

You are mis-interpreting the data ;) The mesh statistics are for the mesh of the object called 'air' both within the object and on the faces. The mesh operation you assigned only enforces the mesh constraint on the faces of the object called 'air.' Therefore, there can exist tets with edges larger than defined within the object called 'air.'

Have Fun.

Thank you very much for the explanation. That makes perfect sence.

Deborah

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Regards
Sajid Mohammed.