In a post on The Tech Block, Lehman writes that he believes that the persistence of leaked parts coming from Asia is an indicator that these components are the actual design of the device.
The pieces, in his opinion, reveal more of an upgraded version, compared to the iPhone 4/4S, rather than a total design change.
The device will feature a unibody design with a two-tone metal backplate.
Lehman writes that “the leaked [iPhone 5] design has three pieces of metal instead of four. It still has two U-shaped pieces at the top and bottom, but this time the two flat sides become one single piece of metal that also comprises the back of the device. That single piece of metal is the unibody backplate.”
He adds, “same properties that unibody designs give to Apple’s laptops apply to this design as well: stronger, lighter, and thinner.”
With the new design, the full glass back of the phone is dropped and the smartphone becomes about 2-3 mm thinner than the iPhone 4S.
“That sounds small, but it’s a huge difference,” Lehman writes. “That’s as much as 32 percent thinner. As a point of comparison, the Retina MacBook Pro is only 25 percent thinner than the old MacBook Pro.”
He continues, “The cell antenna is integrated into the metal case, but there are still separate Wi-Fi, GPS, Bluetooth, and (potentially) NFC antennas to deal with. They need to transmit their signal through non-signal-blocking materials such as plastic or glass.”
“That was why the original iPhone had a black plastic piece at the bottom of the case, why the 3G/3GS’s back was made entirely of plastic, and why the 4/4S’s back was made entirely of glass. This is why there are the two pieces of either glass or plastic at the top and bottom of this design.”
“Long story short, instead of using the entire metal band for antennas like in the 4, the 4S only uses the top and bottom sections as antennas,” the designer writes. “Since the flat sides don’t contribute to transmitting signal and only help with the structure of the device, it makes sense to make them even more integral to the structure. This is what makes a unibody iPhone possible.”
Lehman also explains that Apple’s quest for refinement and functionality are the reasons for tinting the metal housing in the black model and the implementation of a smaller dock connector.