Hi,
Try the double IFA (Inverted "F" Antenna) antenna. It's a printed microstrip antenna. Dimension is about one quater of wavelength. I think that you have just to google "IFA" on the web to find website for design this antenna.
Bye
i m having problem in assigning port in cpw fed .. .
i m working on project where i m using cpw feeding in a band notch monopole antenna wher i m using waveport of size 3(2g+w) and 4h..