i need some example about simulation antenna using feko

[GameKing]

aerial antenna feko

hi all
i'm a newbie, now, i'm using feko v5.2
but i don't understand many problem about microstrip fed and cpw antenna when using feko
when simulating microstrip fed antenna and cpw antenna, i use edge port to excite metalic_face to others but both of the metalics contact with dielectric (not use Green function for infinite planes); so when i run feko, it run error: "ERROR 2586: Feeding an edge at the surface of a dielectric body not possible"
anyone helps me to solve this problem, and send me some example if possible

 

[mvr]

feko dielectric example

In the Help Centre on www.feko.info there is a page with the title"How to feed microstrip lines when using finite substrates". This will show you the way to do it.

 

[GameKing]

feko feeding an edge at surface of dielectric

i tried finding on www.feko.info but i'm not remember on this site, please help me

 

[mvr]

feko antenna example

The edge of the feed must either be placed entirely inside the dielectric or entirely outside, so no part of the feeding edge is allowed to touch the surface of the dielectric.

You using FEKO Lite, GameKing? Why not download version 5.4 then?

 

[GameKing]

example feko

thanks mvr
but it's difficult to make antenna with edge port feed
i used to try doing this method before. but when i compared the result of simulation with hfss software, i recognized that this result is not as exactly so hfss. besides it's not exactly very much: use => not use
i'm using feko full, but not remember, so i can't direct download feko5.4 full

you have some example designed, mvr ? i need the method of simulation feko very much

 

[mvr]

I attach two images - one showing how to place the feeding edge inside, and the other placing the feeding edge outside of the dielectric.

If you really need to feed on the edge of the dielectric, you can use the FEM current source with FEM/MOM (volume meshing). In version 5.2 this is not available in CADFEKO - you will have to use the AF card in EDITFEKO in 5.2.
In version 5.4 you simply add a line port and current source in CADFEKO.

 

[GameKing]

yeah, mvr
i think that is not nomalized method about simulation microstrip antenna.
when to place the feeding edge inside, apart of substrate ( may be small or very small) was not transmited by electromagnetic field. This is no problem with the width, but it is problem with volume (of substrate) => not exactly
and when to place the feeding edge outside, apart of line patch ( may be small or very small) was out of substrate, however apart of line patch was radiated out of freespace => not exactly
we know that with microstrip antenna, small or very small elements are very important

Do you think about this problem, mvr ??

 

[mvr]

yeah, mvr
i think that is not nomalized method about simulation microstrip antenna.
when to place the feeding edge inside, apart of substrate ( may be small or very small) was not transmited by electromagnetic field. This is no problem with the width, but it is problem with volume (of substrate) => not exactly
and when to place the feeding edge outside, apart of line patch ( may be small or very small) was out of substrate, however apart of line patch was radiated out of freespace => not exactly
we know that with microstrip antenna, small or very small elements are very important

Do you think about this problem, mvr ??

I agree, this "workaround" is not ideal. For very accurate impedance calculations, yes, maybe not so good, but I think for directivity calculations this feed is not so bad. At low frequencies, say a couple of GHz, this would not cause any significant pertubation of the results, impedance or directivity that is. But at, say 10 GHz, yes, this feed would not give very good results.

I think they should address this, but as FEKO is a MOM code, i.e. working with currents, it is not as simple as in e.g. CST where the FIELDS are modelled and a field source is placed in between the microstrip and ground. With the MOM, one can not apply a FIELD distribution between the microstrip and ground.

But FEKO has FEM, so maybe they can extend the FEM to have field sources, I hope.