Helical Antenna for dual bands GSM :)

HI Everyone...

I just joined this forum for help in my Final year Project...Basically we are trying to design a GSM signal strength enhancement system! It would be requiring a dual band outdoor omni-directional antenna. We are first working at Helical antenna...

I would highly appreciate any information you guys can share with us...

I have a few basic questions about helix:

1) Is there any physical difference between the structure of normal and axial mode antenna?

2) Can anyone of you provide any HFSS file that contains a helix structure for dual GSM bands....Any info regarding this will be highly appreciated..


I hope i enjoy my stay here...


Thanks a bunches