Strange S11 for Horn Antenna in HFSS!!

[imtiaz369]

Hi everyone,

I recently designed a horn antenna in HFSS using the Antenna Toolkit. The design specifications and dimensions are for it to operate up to a maximum frequency of 40–45 GHz. However, the simulated S11 response shows that the antenna is working (below -10 dB) up to 80 GHz, which doesn't make sense for my design. The S11 response also appears unusually constant over the entire frequency range.

• I used the radiation boundary for the setup.

I suspect something is wrong with my simulation, but I’m unsure where to start troubleshooting. Could this be due to boundary placement, mesh settings, or something else?

Attached is the S11 plot for reference.

Any suggestions on how to identify and fix the issue would be greatly appreciated!

Thank you in advance!

 

[imtiaz369]

E field Mag at 33GHz