AnandTech’s iPhone 4S Review
Brian Klug and Anand Lal Shimpi:
To re-state the evolution that Apple has taken with this design, the GSM/UMTS 4 had one transmit and receive chain, the CDMA 4 added a second receive chain for diversity, and the 4S now has two receive chains and the ability to switch between two transmit chains. The result is that the phone no longer is prone to fading on either the forward or reverse link due to being held near the feed points for one chain.
The iPhone 4S antenna works much better for me than the iPhone 4 one did, and it’s even an improvement over the 3GS. In particular, it almost never has trouble acquiring my 3G MicroCell, whereas the 3GS often needed to be rebooted.
