WIFI problem or not?

I keep on comparing my Iphone5 to the Iphone 4s and Ipod touch of my roommate. His Iphone and Ipod have full bar of the wifi connection indicator but my Iphone5 has 1 or 2 bars or more often does not have wifi indicator. We were 15feet away from the wifi machine, but my friend's gadgets has full connection, mine does not have, i need to change position to get one.. so how is that? does my iphone 5 broken?