Extended Inner Conductor Antenna Simulation in HFSS

Hi,

I'm trying to simulate a type of coaxial antenna as attached. The outer conductor is stripped off at one section, exposing the dielectric. And the inner conductor is extended.

This design is suppose to give a far-field radiation pattern similar to a half-wave dipole. However I tried modeling it in HFSS, I kept getting 4 lobes, instead of the desired 2 for the radiation pattern, and the S11 is horrible.

CAn anyone advise me where are my mistakes? Thankz!

Cheers
huiyuzz

HI,

regarding this project, I think i've got my excitations wrong as I cannot even obtain any e-ield radiation. I'm confused with the port assignment. How many wave ports shld i use? where and what size according to the Figure?

Cheers
huiyuzz

Please try the attached file and let me know the result.

Oops,

Thanx for the help: wlcsp. tried tat. Gives a less than -10dB S11..

Hmmm.... cud it be my model is wrong (wrond interpretation of the figure), not with the excitatation?

Puzzled....

huiyuzz

What the about the radiation pattern. Is it as you expect ?
Do you have any measurement data you can compare with?
Using air as dielectric is a bit strange.

Is that figure the only information you got about the structure?

I think there is something incorrect for your port definition.

I'm onli using a waveport that covers the cross-section of the dielectric and inner conductor. Tried to define integration line from inner conductor to outer conductor and vice versa, doesnt seemed to make a diff.

My solution type is "Driven Modal".
Hmmm..... I just know my model is wrong, but dunno where is the prob.. been trying to trial and error to find where went wrong..


huiyuzz

After struggling for 1 month, I still cannot get the right results. One evidence to prove my simulations wrong is the E-filed intensity plot.

Attached is the plot given in the paper. And the one I've got.

*scratch head*

Where could went wrong?

hi,wlcsp, I dont understand why you can add the pec cap there, I thought you spoiled the wave port on that plane.
Best regards,