help meeeeeeeeee!!

I am simulating a FM dipole antenna ithat operate at 88 -108 Mhz in HFSS . But this anten operates wrong.
could do anybody help me?

if you'll attach your model it is more probable that you'll be helped.

here is this antenna that i am simulating! I hope that you can help me!

thanks

There are no specified clearly dimensions fo the antenna and tubes diameters. Don't you have more exact geometry specification of the antenna?

yeah! this is antenna that I simulated in HFSS.

help me, please

hi!

Do you have a example about VHF/UHF antenna that is simulated successfully?
Can you send it for me?
I simulated many times but i don't success.

Thanks!

how about using CST Microwave simulation you might get a success

exactly, I simulated with ansoft HFSS v.11. I didn't use CST.
I tried many times to simulate somes kind of UHF/VHF antenna but i still successed.

Can you guide me the way to simulate kind of this antenna.

thank you!

You have not included in the excitation in your simulation so how do I know that you have simulate correctly. Pls attach your full simulation (with the excitation here).

I think that i simulated incorrectly.So, if you have a example about UHF/VHF antenna that you simulated successfully, can you give me?
I want to reference your example to simulate another antenna.

thank you so much!

I've sent you a working simulation file, but pls improve on it because I did not spend much time optimizing it.

Dear Micky74

Thank you for your help!

I recived your file but i can't not open this file.I tried to change .pdf to .hfss but i can't not open this file.Can you send me Hfss file?

thank you so much!

Added after 3 minutes:

Dear Micky74

I opened the file that you sent me!

thanks !

Dear Micky74

I changed some parameters of the antenna that you sent me but the result is not good. can you simulate again this antenna and send me, please?

Thank you so much.

I thought I've sent you an antenna model that works from 88 to 108MHz? Basically you just have to adjust the arm length of the dipole to get even better return loss. Or you can change the shorted portion at the coaxial outer sleeve.

I'm not sure what parameters you have changed so that it won't work now. Why don't you send me your revised version and I do a check on it?

The bandwidth of simple antennas, even with a good width to length ratio at VHF is not going to be sufficient to cover 20 MHZ. Broadcast TRANSMIT antennas are fixed frequency and their bandwidth goal is
determined by the width of the transmitted signal. Broadcast receive antennas with wide bandwidth are generally a compromise. (unless you can design for
a single channel.) 468 divided by the frequency in MHZ will give you the length of a dipole antenna,
in feet, with a 70 ohm feedpoint resistance at the frequency, degrading to a complex IMPEDANCE as you move up or down, physically thicker components will provide better greater bandwidth. Rather than try to work backwards from a "design program" you might want to read about real world antenna design in the Radio Amateur Handbook published by the American Radio Relay League (ARRL). Radio amateurs, since they are free to move about 144 to 148 MHZ in the states for example, prize wide receive AND transmit
bandwidth antennas with feedpoint impedances which vary as little as possible. (easier said than done) You really have to look at the whole system, the source (transmit) or load (receiver) impedance, the connecting wire or "transmission line" impedance, and the impedance at the antenna terminals at the frequency of interest. Perhaps your program is not working because what you are asking for can't be done. In practice, the "folded dipole", a flattened loop length antenna (length - in feet- of 468 divided by frequency in MHZ) with one of the two equal length long wires split it the center as a two connection feed point is well worth looking at. If it looks like the "T" shaped antenna which gets packed in the box with many FM broadcast receivers, it is because IT IS.