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I am expecting the reflection co-efficient (db) least than -10db but i have no clue where i am doing worng??
Hello,
I just ran one simulation without the line at the end of the feeder and got the same result as yours: No resonance observed..
It means that the line has some effect on the resonance.
And I saw the circle on the ground moved in your model (model-mod.cfx).
So I have some doubt that your antenna is resonant at the simulation frequency.
Could you share any referecne paper regarding this antenna design?
How did you know if your antenna is resonant?
Best regards,
Jaehoon
this is the reference paper of that antenna design
I checked your model with the pdf and found out there are some drawing (small) mistakes, but those mistakes are not the cause of the reflection coefficient (~1).
I think the main reason is because your simulation frequencies are not enough.
Please increase the number of the simulation frequency as I did in the attached model (5 → 51).
I modified your models as below.
The following is the simulation result.
thank you what I need to do….in order increase my reflection coefficient to the 0.2 ( -13 in db) and also improve the gain
and in order to improve reflection coefficient I tried to apply the optimisation..but it thrown some errors…….
errors in this picture
and followed some steps to optimize
There seems to be no issue in defining the Feko optimization (Goal and Parameter).
According to the error message, the error is related to the symmetric setting.
Honestely, there are some symmetry issues with the Feko 2025.1 version, although the symmetry setting is useful to make a balanced mesh and speed up simulation.
So if you want to keep using Feko 2025.1 verson, please unselect the symmetry as shown below.
However, if possible, I'd like you to use the Feko 2025 version or older version, where you can use the symmetry.
PS) The symmetry issue will be fixed with Feko 2026 version.
ok, will I get desired reflection coefficient (-13db) and gain (5 dbi ) if i perform optimization? and also how can i improve them without optimization ?
and while i am running optfeko without symmetry in warnings it is showing
can you check and fix this problem ??
The warnings looks not that critical in running OPTFEKO.
Before investigating the error 21061, I'd like to understand why you want to run the optimization, because all the dimensions of the optimzed antenna are already given in the paper.
I think your next task would be to check why Feko's result is different from the paper.
If I share my opinion, the dimensions given in Table 1 of the paper are not well matched with the antenna shapes in Fig. 1 and Fig. 3. (For example, two centers of the slots look not coincident in Fig. 1 and the bottom slot in Fig. 1 and 3 looks quite bigger than the given dimension in Table 1. )
So I'd like you to confirm the antenna dimension with the paper authors.
PS) I think you added too many variables to the optimization parameter. I am not sure Feko is able to find the optimized result by changing the variables.
