Hardware experts are not buying the NFC rumors behind the mystery EMI-shield square discovered in a leaked iPhone 5 display assembly. In fact, they say “you can almost entirely rule it out.”
According to the tech-savvy bunch at AnandTech, if Apple’s iPhone 5 does ship with a metal back plate, as all the hardware leaks have indicated, “it's highly unlikely that NFC is in the cards for this generation. In fact, given the very little space at top and bottom dedicated to those glass RF windows, you can almost entirely rule it out,” reads their analysis.
The technology experts note that the best NFC antennas are basically big inductors that “work using a magnetic field coupled between a host and peer device.”
The NFC antennas use up a lot of wire on a big 2D plane. Inside smartphones, NFC antennas are flat spirals on a PCB, as shown above. AnandTech believes it goes without saying that “having a huge ground plane (the unibody metal back case) in the way of your NFC antenna will seriously degrade performance, thus only the top or bottom windows are logical places to put it.”