Simple Wire Dipole Resonance problem

Hi,

I have a wire dipole antenna which i modeled as a driven element for a yagi at 2.45 GHz. When i was modelling in hfss i used a lumped a port between two wires. But when i built it on an SMA it seems like there is an extra resonance introduced to the dipole right after the main resonance. Does anybody has an idea about the source of the problem? -

I do not know why any modeling is needed. If you cut a 0.47 lambda wire, i will resonate at the corresponding frequency.
If you built such dipole, how you conected it to the SMA connector? What matching you used?