Apple has changed the antenna in the new iPhone 4S so that the cellular radio in the phone can choose between two antennas, depending on which one is sending or receiving signal best. These two antennas are part of the stainless steel band that wraps around the sides of the iPhone 4 and the new 4S. On the iPhone 4 this band is split up into several antennas so that one piece does Wi-Fi, another does GPS, another does Bluetooth and still another does cellular.
But on the new iPhone 4S, the (GSM) cellular antenna is divided up into two pieces. So if you apply the death grip to attenuate to one piece of the cellular antenna, the radio will, in theory, switch to the other piece that isn't being gripped. So you'll have have to apply a Double Death Grip (see image) to squelch off cellular service to the new phone completely. That move is usually seen only on Star Trek and in pro wrestling rings.
But there's more: the new 4S is a "world phone," meaning that it contains both a GSM radio and antenna and a CDMA radio and antenna inside. Obviously the "antenna band" running around the phone is being cut into smaller and smaller sections. How this will impact reception/transmission of the various wireless signals is yet to be seen.
"Improving on the innovative stainless steel external, dual-antenna design of iPhone 4, iPhone 4S is the first phone to intelligently switch between two antennas to send and receive," the press release reads. Actually, the new antenna concept is nothing new at all--it's just new in consumer handsets. Such "diversity" antenna systems have been used in other types of wireless devices for years.
The network engineer and the antenna engineer I spoke to yesterday after the 4S announcement yesterday both said that the new antenna design is likely to produce only modest reception gains. One engineer got the distinct impression that the new antenna part of the 4S announcement yesterday was more about hype than anything else.
These are opinions of course; we won't pass official judgement on the new antenna system until we're able to test it in the wild. In tests we performed last year, we found that non-iPhone AT&T handsets (BlackBerry, for one) could maintain voice calls in thin cellular conditions far better than the iPhone 4. We'll be interested to see if the iPhone 4S shows any improvement in call quality and drop rates in similar circumstances. On the data side, we'll compare throughput speeds on the iPhone 4 with those on the new 4S. So stay tuned for that.
The other thing that made me skeptical of Apple's new antenna system is the limited information that came out about it yesterday. Many questions remain unanswered. "iPhone 4S now supports twice the download speed with HSDPA of up to 14.4 Mbps and iPhone 4S is a world phone, so both CDMA and GSM customers can now roam internationally on GSM networks," Apple said in the announcement. But the speed increase to 14.4 mbps maximum throughput is the result of an upgraded radio chip inside the phone, not the result of the antenna, as Apple seems to suggest.
Also, when Apple talked about the new antenna system and the speed increases yesterday, it referenced the GSM parts of the phone. What about the CDMA parts? Does the CDMA radio go up to 14.4 mbps too? Is the CDMA antenna inside the phone also split in two? If the answer to either of these questions is No, it doesn't bode well for Verizon and Sprint who will sell the CDMA flavor of the phone. And it goes without saying that the 4S won't run on the fastest wireless network in the land, Verizon's LTE network.
So regardless of the antenna details and speed boosts, the iPhone still is not a true 4G phone. How much longer do we have to wait?