Ground plane and parameters ..

[Sara88]

i'm supposed to design a fractal antenna (Dipole koch curve), however, there is something really bothering me and cant find an answer for it.

How to define the parameters and dimensions of my PCB's (FR4):
1- Ground clearance/plane.
2- Feeder
2- Thickness, width, length.

(my frequency 875 MHz, with return loss at least -6dB)

 

[zorro]

Hi Sara,

Sorry, this does not answer you question. But why do you want a Koch curve antenna? It was demonstrated that it has not advantages over standard and well known antennas.
Regards

Z

 

[Sara88]

its ok .. it is my final year project !

i can't find any answer.. everytime i read more i get confused.. so i need help if you have some valuable references that could be useful, i'll be thankful

 

[zorro]

Hi Sara88,

In his book "Electrically Small, Superdirective, and Superconducting Antennas" (John Wiley & Sons, 2006), R.C. Hansen classifies fractal antennas among "Pathological Antennas". Hi gives explanaition and references. Try to take a look at it.
I have an interesting reference that gives results specifically for Koch fractal, but I don't have it now. I hope i could give you the reference tomorrow.
Regards

Z

 

[zorro]

Hi Sara,

I intended to say that maybe your efforts wold have a better result with another type of antenna.
Nevertheless, if you design a dipole, the dielectric substrate of the PCB acts mainly as a support for the radiating part of the antenna. There is no ground plane on the other side of the dipole.
The ground plane can be part of the feeder, balun, or matching network using microstrips. Mainly in function of these parts (not the dipole, although he substrate affects it) the thickness should be selected.
I hope this helps.
Regards

Z