Ok, so I've been simulating the tag antenna I made, it's attached here. I inserted a lumped port in the center which is where the IC chip is supposed to be. I used a vacuum as the radiating box and simulated. I set the antenna material to Perfect Conductor. But my S11 is off, it doesnt reach -10dB, and it goes past 1 GHz. What am I doing wrong?.. I did not use a substrate since the Hammer tag is a "sticker" tag. Any help please?... One of the members here sent me a sample antenna design in HFSS and it works just fine. >_<