Fractal antenna desing problem

[vkalariya]

HI all

I am designing the Fractal antenna for the multi-band application.
First I design the antenna(Square patch) for one frequency that is 1.5 GHz and after that I want to design the same antenna radiate at 5.5 GHz.

But when I make that radiate at 5.5 GHz by making the iteration in square patch then my first frequency is changed to 1.3 GHz.

So, can any one say that why this happened ?
and
What is the possible solution of the problem. ?

 

[snkhan]

Its seem to be quite tricky design. I wold suggest you to change the size of 2nd and 3rd iteration trough parameter sweep.

 

[vkalariya]

Thanks SN Khan

well i am using the ADS2005A and I am new to it so can you tell me that how to use the parameter sweep with the layout window in ADS.

And by changing the second and third iteration frequency of the second resonance is also change.

 

[v_vishal]

see the paper of IEEE on fractal Sierpinski carpet antenna paper and you can find the solution of this proble.

 

[viv555]

hi Vkalariya

Try to design the antenna for the first frequency and after see the current distribution and and find out the lower current distribution area and make second iteration on that area i think it will work fine but reduced the S11 for the first frequency.

 

[vivek1214]

search for the fractal paper on this community might be you can get more paper on fractal antenna.

 

[mwband]

If you want to add an iteration to your square patch then you'll find that the current path length of the 1st mode will become longer than a single square patch. One possible way that you can do is designing the antenna to operate at above 1.55 GHz for a single patch.

regards,