What's the best software for simulating a dual-band PIFA?

i'm having problem with the simulation of a dual-band PIFA (GSM900 and DCS1800)...
which is the best software for the simulation?
i'm using Zeland Fidelity.. but already doing it for months and i still cant get the results...
help!sos!
thanks alot

Hi, pennylsn:

You can send the files to support@zeland.com and we can help you. You can use either FIDELITY or IE3D for PIFA antennas.

Best regards,