wifi problem after lcd and back cover replacement

hello, i'm Dan, i have a problem with my z3 compact's wifi. I replaced the lcd and the back cover, and the wifi don't work good... The signal at 2,4GHz is so bad and at 0 mb in download, with the 5GHz is a bit better but not enought. I don't know where is the wifi antenna, and if i could touched it or broked it when i moved the motherboard or others.