HFSS setup of bistatic radar: how to reuse a mesh

[alex_gaas]

Hi everybody,

I have to simulate the scattering of a bistatic radar with a metal ball target.
I am using the FEBI option so both the antenna and the target are enclosed in a box (picture one). In this way I bypass the problems of a large mesh.
In parallel I am also using another set up environment with only one box (picture two) to estimate the crosstalk between the two antennas.



After simulating the two hfss files I subtract the two frequency response to obtain the target one.
In time domain this means that I see an UWB impulse delayed by a constant as in a normal radar.
By simulating the structure with the distance of the ball variable I should see the radar attenuation but this is not happening.
The problem is that for a very low backscatter this process of subtracting has some error because the mesh in the two files are not the same.
So the question is how to reuse the mesh to overcome this problem??
Or other simpler solutions are very welcomed!
Cheers


Alex

 

[dragosmihaisg]

Hi Alex,

why not try to solve the problem with your target included except that the target material property is vacuum, in this way you can force the mesher to create the same mesh for both cases and compare (subtract) you results.

Cheers
Mihai

 

[alex_gaas]

Hi Mihai,

thanks very much for your reply. I've tryed the two scenario but I get the following error:

"The source and target models should be geometrically equivalent"
"Failed to presolved data"

Any suggestions?
Cheers,

Alex

 

[dragosmihaisg]

Hi Mihai,

thanks very much for your reply. I've tryed the two scenario but I get the following error:

"The source and target models should be geometrically equivalent"
"Failed to presolved data"

Any suggestions?
Cheers,

Alex

Hi Alex,

Do you mesh the target? Is the target a PEC? Do you mesh inside the target?
I think what happens is that your target is PEC the solver does not mesh it inside, while where is not here the volume is meshed hence the difference in mesh.
You may need to try to mesh inside your target solve the probelm like that, then use exactly the same mesh but change the target properties to vacuum, and resolve it (do not allow the solver to change the mesh anymore), it does not need to readjust the mesh once the target is not there anymore.
I hope this help.
Cheers
Mihai