Why MWS and HFSS gives so different results?

The structure is quite simple...two monopoles (feed by waveguide) in free space...I have simulated these structures both in HFSS and MWS...the results are quite different...first of all resonance in S11 is at different frequency for MWS and for HFSS...second, the magnitude of the resonance is quite different...can somebody tell why the results are very different? I have attached both the MWS and HFSS project files.

are you sure you attached correct file?

Regards.

yes...why? did you get some errors?

I didnt see the HFSS project file there.
And I didnt find any problem in CST from the simulation results.

When unzip this file, some error generated, seems that there are few subfolders there, but those folders can not be opened. very weird folder name, can not be identified by windows. After that, I can see only CST file.

Regards,

it may be due to the RAR version...please find the .zip version in the attachement below

Your HFSS is not correctly setup. You may check my modification.
No nay problem for simulation results comparison.

Regards,

The resonant frequency has small difference, because I changed the radius of your cylinder in the model, the project file you attached is not properly built.
Simulatino freuency range is 2~8Ghz, please remember the raidation boundary should be at least quarter wavelength away from the structure. Waveport inside the radiation box is used.

Regards,