Dear zinal,

if you run the simulation with 20 adaptive passes which is default in HFSS. then u can choose a frequency some where around 3 GHz and use a sweep from 0.8 to 7 GHz.

The main criterion is to get a good convergence, else use some mesh appertains.

Okay sir Thank you very much for your time and considerations.

Sir,

I have tried it. Instead of 3GHz it give me better results for 2.5GHz.

Can i used it as solution frequency?

On which basis/concept you have choose 3GHz?

i think mohan means 20 not 200 , is it ??

So it is the frequency at which my antenna design give me good results..for the area..for which i have design my antenna..Am i right Mr. Mohan ?

So for 1 to 6GHz, If i get good result for 2.5Ghz...can it be my solution frequency ?

Zinal,

The solution frequency is decided before launching the simulation. The simulation is done beacuse we dont know which frequency is the best. The criterion is the convegence in the solution domain.

Okay Sir.

yes anuraag misra is 20,i typed wrongly

yes zinal

Yes sir Mohan ?

Solution frequency is the frequency for which the meshing operation is assigned. As in the case for UWB antennas, in multi band antennas the solution frequency better be the highest one for smallest mesh. Another thing, the good results you are getting doesn't necessarily mean they are correct. You need to measure to know whether they are correct results or not.

To Ahmed Sir,

Can you please suggest me which frequency I have to choose?

If the bands you are interested in are 1.8, 2.4, and 5.2 GHz, then you may choose 5.2 GHz as your solution frequency and optimize your design to get the required results while 5.2 GHz is the solution frequency because most likely it will be the closest to measurents ..

Best regards :)

okay sir.

Thank you very much for your time and considerations.

I will try it.

There are two ways.

1) Assume total band at at time and find centre frequency. Take that as solution frequency and analyse for full band of interest

2) Assume three individual bands and take one by one as a solution frequency and check. You will have three independent exercises. EG  Take 1.8 GHz as centre frequency and analyse between 1 to 2 GHz and so on.  

I think your solution frequency must be the center frequency of entire frequency domain(1-6GHz). But for optimization you must choose the center frequency of the each band.

Best regards,

there are so many ways to give solution frequency. first try the lowest operation freq and highest operation freq as a solution freq and compare the results. the other way to obtain a solution freq is find a maximum return loss of the structure using eigen mode ananlysis in the hfss. 

You can add a parent solution setup where the solution frequency is 6 GHz, then add many solve-dependent-setup as there are your frequencies of interest.

For each dependent-solve-setup add appropriate frequency sweep.

Best regards

To Hadi,

What should it be but ? average value ?

6-1/2=2.5GHz.....?

Or anything else sir?

To Asokan,

Hoe to find a maximum return loss of the structure using eigen mode ananlysis in the hfss...?

I really do not know about it.

Regards.

To Amipara Sir,

If I want to go with the first one then what should be my solution frequency?

Regards,

For large bandwidths, the geometric mean works out better than the arithmetic mean, so the center frequency should be:

fc = Sqrt(fL fH) = Sqrt( 1.80 x 5.20) = 3.06GHz

instead of the arithmetic mean:

fc = 1/2 (fL + fH) = 1/2 (1.8 + 5.2) = 3.5GHz

To Ahmed,

Thank you very much sir.

Regards.

Dear Zinal

arithematic mean frequency may be central frequency but some how it can produce error for data correlation, i think geometric mean may work out properly but better way you try for your occurrence where you can get better gain. 

For HFSS, it uses FEM method. the frequency solution is the estimed frequency you want for your antenna application. I advise you not to make simulation on the whole band frequency. it will be less accurate but dived the band into subbands

To Ouadih,

Is three any other formula for it?

or same as above discussion?

There is no formula for that but just a good sense  !

okay. which freq you suggest me?

i didnt understand ur answer abdelhakim el ouadih how we can get sub bands. suppose we design the antennas for multiband or wide band.

To Asokan,

I think as below...

1.Set solution frequency =1.8GHz and sweep from 1.4 GHz to 2.2GHz and check S11 response.

2.Run a new simulation and set solution frequency = 2.45 GHz and sweep from 2.2 GHz to 2.65GHz and check S11 response......and so on....

i got it. but suppose i deciding the antenn to be resonate at excatly 2.45Ghz then i do the same procedure . and second thing is in multiband operation how determine...the same method is applicapble to all designs

thank you so much for ur reply. 

As zinal understand. The solution is to put in setup solution the frequency of the application you want as 2.45 Ghz for wifi and bluetooth. The good sens is to forecast the resonant frequencies number viewing the antenna shape and dimensions.

You are most welcome.

In the first place, how did you design it? Simulation with HFSS can be run at different discrete frequencies as well as over a spectral band

Hello ZInal

i have also designed patch antenna which is actually PIFA (Inverted-F) but I am not getting good return loss at my three center frequencies  which are 2.09,3.74 and 5 GHz?

Can you help me with that?

sure...message me dear

its depend if you want on single freq or on different ranges dear

Ahmed and Ornella Leonardi, explain very well for solution freq, and your interest of freq bands. i.e. you can take height freq, and sweep can be added in multiple bands.