Problem in simulating circulardisc monopole, Help me!!!

I'm trying to simulate a circular disc monopole in a paper (the pdf attachment file) to test the result. All the dimensions are the same, but the result is not the same. My result of S11 is so good that I am sure I have some thing wrong.
I am using HFSSv10.
Can somebody help me find out the error

Thank you so much

HI

I downloaded your files, and simulated it, I found the paper gave the results by CST stidio, it will be much different with HFSS. And notice that HFSS is based on FEM, a frequency domain algorithm, and it is not proper to cover a large solution frequency, you 'd better divide the frequency into some small ones, for example, 1-3GHz, 3-5GHz, 5-7Ghz, 7-10Ghz... hope this helpful!

Regards
Edmund

Thank you, I will try. I hope it will work

I don't know why, but the result didn't change.
Am I wrong in any steps?
Is the waveport dimensions incorrect? or Radiation boundary incorrect?
I need somebody help me! :((

Select waveportand plot vector-E, make sure that the Efield is right, if not, change waveport dimension.

Edmund

WTDOng shalom,

Please correct your model as follows:

1) You are interested in a sweep up to 12 GHz (right?). Please change Setup1 mesh frequency to 12GHz. You cannot expect a mesh in 3 GHz to give accurate results at 12 GHz.

2) If all you are interested is S11 then change Sweep1 to be interpolating sweep (from 0.1 GHz to 12 GHz + extrapolate to DC). HFSS has no problems in simulating USB antennas. Once you have the resonance frequencies you could add descrete sweeps on these two or three frequencies to calculte fields (for current plots). So you should have one Setup and two sweeps (interpolating for S11 UWB and discrete for selected frequencies in which you would like to see the radiation pattern or fields. You could calculate both S11 and radiation pattern on all frequencies using about three fast sweeps (between 12-3, 3-0.5 , 0.5-0.1).

3) The paper states that the ground plane also resonates. That means that you need to move the radiation boundary away from the ground plane (increase the widht of the airboxes to 2*W). Your current radiation boundary does not allow the ground plane to resonate. Please also notice that the Q factor of the resonances depends on the FR4 losses (which are not specified in the PDF file).

4) Increase the height of the airbox (at least by factor 2).

5) Delete all the manual mesh operations. They are not needed. For greater accuracy, select the circle and assign a surface approximation mesh operation with normal deviation of 5 degrees (the terahedral mesh will use 72 facets per circle instead of the current 16 facets per circle).

Regards,
Itai