dipole antenna with balun

we normally in CST MWS as well as in HFSS we use wire port to excite halfwave dipole in the centre.
now i have constructed a dipole and have used coaxial cable as feed transmissin line
as coaxial is unbalanced line and dipole is balanced so i have to design balun as well.

now when i simulated this actual dipole along with balun i am not getting the results as expected.
i am using lambda by 4 balun

if anyoner simulated such kind of dipole with balun i would like to have their comments on this

thanks

I think the software perhaps is not good at siumalting the balun. And the ambda by 4 balun is very easy to make in practice. You can make it and test it.
My antenna level is not high,but i only want to say sth.