Learning Forum

[673755156]

In HFSS 3D layout, when setting the stackup, validate will report an error after setting the etching factor. Adjust the etching factor, still report an error.

[Mrinmoy Bharadwaj]

Using the etch factor feature causes the cross-section of traces to be modeled as trapezoidal instead of rectangular. This can trigger warnings if something about the geometry complicates the process of adjusting the cross section. If you double click on the warning messages the view will zoom to what HFSS believes is the problematic geometry. In the case of the TOP layer HFSS might zoom to a thin sliver of metal. Kindly delete this sliver and try again.

[673755156]

I tried this method, but it didn't work.

Later, when I removed the simulation model of the component, the error disappeared, and when I added the simulation model, the previous warning appeared again. What is the reason? I'm emulating the S-parameter.

[Mrinmoy Bharadwaj]

Hello wang jian,

Sorry for delay in reply.

There are many geometric arrangements that will cause etching to fail -- if it attempts to etch and the resulting geometry is invalid, it will abandon the etching. When the geometry is etched, a true 3D solid needs to be created for meshing. One complexity that can happen, for example, is where metal planes almost 'pinch-out', thereby forming a narrow neck, etching can result in the thinning of the material thickness at the neck. Also, it has to be ensured that etching doesn't affect the geometry around ports; otherwise in the final mesh, the port would no longer be of the expected geometry. It is difficult to accurately pin-point the actual reason for etching failure in your model without having a look into the model. Please reach out to Ansys Technical support if you plan to have your model checked by us.

Hope this helps.