Help!!!!! Yagi's HFSS Problem

hello i am doing my undergraduate thesis

i had made my yagi design for WLAN application

but i made some mistake..

the radiation pattern is wrong

i got no gain, and directive tab,,,

can anyone fix my problem??

i have attached my file...

someone help me pls

There are several very weird things about this project. First, why is your antenna inside a waveguide if you care about Far Field Gain and radiation patterns???? You have basically enclosed your antenna inside a metal box by using a PEC boundary on all faces of the airbox. Also, your waveport that you use to excite your antenna is inappropriate (wrong) as no power will enter your dipole. You basically shorted your entire waveport by having its entire face a metal. You would be best served to draw a rectangle between the dipole leads and assign that rectangle as a lumped port. You should also remove the PEC boundary, remove the waveport excitation for the waveguide, and reassign all airbox faces to either a PML (preferred) or radiation boundary. Also, you need to upgrade to HFSS 12.1 as it is much more efficient in solving these simulations and it also has an IE solver which is nice.

hai I newbie hfss
I got same problem when i try to find far fields radiation pattern result of my 3 element dipole with 1.9 ghz
please some one help ... how many did i must to add dipole for to get max result gain antenna dipole
Where i can find to change gain db or watt to dbm / mW in HFSS option to result report project