About yagi antenna simulation

[S.Quoc.S]

Hi , Im simulating a yagi antenna with 6 elements with the haft-wavelength dipole driven element at 2.4Ghz using hfss v15.
The radiation pattern, gain, directivity are as expected :grin: But the input impedance is somewhat i dont understand. As i know the input impedance of an dipole is about 73 +45j(ohm) but the Z parameter graph say about 200 +60j ohm.:-?
I also simulate a haft-wave dipole only after, but z-graph is not about 73+45j :?:
I dont know if my simulation is correct or not. Can someone tell me what is the reason about the impedance? Thanks in advance.
Here are my simulation files:
yagi
dipole

 

[mike65535]

Without looking at your design, I'd have to say that it's expected.

Commercial Yagi antennas typically have some kind of matching network (Gamma, Delta, etc.) to tune the antenna impedance to near 50/75 ohms.