Learning Forum

[Nooshin Valizade Shahmirzadi]

Hello Ansys support,

I am simulating an antenna in the frequency range of 60 GHz -90 GHz. When I excite the antenna through a lumped port and I check the deembeing option box for lumped port, my reflection coefficient (S11) is well below -10 dB. But, when I leave the deembeding box unchecked, it violates -10 dB in some frequencies over this wide frequency range. Based on what I read in Ansys forum, removing inductance effect of a lumped port doesn't have that much effect on the frequency response. However, in my case, I observe such a significant effect. Could you please guide me about this issue? Which response is reliable? Deembeding or undeembeding results?

Kind regards,

Nooshin

[Nathan Bertrand]

Hello Nooshin, in some cases it will have more of an impact when deembedding options is enabled as you have observed.

Can you use a waveport? If so, then you wouldn't have the same added inductance as a lumped port and you could deembed distanace of a waveport if needed.

To understand the inducatance of the lumped port you could use Q3D on the port alone.

Overall, it's hard to tell whether you should be using deembed or not. Deembed could work effectively, but it's also not precise. If your design is right on the edge of passing or failing depending on deembed enabled or disabled it may be best to use waveports as I mentioned above. Or you can perform other simultions with different ports or port-setups to understand the if you are getting the most accurate results.