The battery door is not an antenna. It is certainly not. This is so wrong it made me register just so I could come here and make sure no-one buys this load of crap. And the door is metal because its a heat sink for the battery that gets warm.
Even if the door was a patch antenna, its the wrong size for the frequencies. But this is irrelevant because its not an antenna. Period.
For those who need convincing- go into system settings and look at the signal strength measured in dBm. Now remove the battery door.... if the battery door was an antenna that number would drop substantially.. by like 10 or more (probably much much more) dBms.
The port near the usb could be an RF connector, its hard to tell. It could also very well be for an external GPS antenna too though.. just a thought.
Source- Not being retarded.