antenna design problems

hi..
i have problem designing stacked antenna.i need to design dual resonance microstrip patch antenna. my frequency range is 1.8 to 2.2 Ghz.my problem is my upper patch subtrate is high (im using foam with height 60mm).ad lower patch using air with height 15.2.when i reduce size of height ...i not able to achieve dual resonance.can anybody recommend other subtrate with its standard thinkness.I also wanna know how to determine size for upper patch, it is smaller than lower patch or bigger lower patch.is there any method to find it?


regards
alan

refr microstrip antenna design handbook

Hi alan6449

This paper exactly what you need. and dual Pol.

pl

hi i have not enoguh points, so can you send this to my e mail. huseyin_itu(at)yahoo.com