urgent!!!balun for printed dipole measurement

hi,

does anyone have the experience on balun used for printed dipole measurement? i am working on the planar printed dipole. i have made the TRL calibration kit for measurement with VNA. but the measured results were very bad. why? does it mean the balun should be included? how to design a easy balun ? the deadline for my project will coming soon.

it is urgent and important.

thank you very much in advance.

well, I saw one printed dipole in one company,they used it as one referenced antenna,actually,it included balun,i remembered they connect one arm to outer conductor,i think it should be 1/4 lamda

thank you very much for your reply.

but i didn't understand what do you mean on 'it included balun,i remembered they connect one arm to outer conductor,i think it should be 1/4 lamda'.

could you explain more details?

You can use a Duncan Minerva printed balun.on front side there is dipole with slot between the arms.from back side there is bent microstrip feed which is extended lamda/4 from the slot.