Apple has redesigned the iPhone 4's antennas for Verizon, perhaps to foil the "death grip" problem that roiled AT&T customers last summer, an expert said today.
"They've moved things around, and my guess is that they went to a dual antenna," said Spencer Webb, an antenna engineer with nearly a dozen patents to his credit, and president of AntennaSys , a mobile device antenna design and consulting firm.
Webb was reacting to photographs that have been published on the Web which show a different configuration for the slots in the external stainless steel frame, which houses the phone's antennas.
Shortly after the introduction of the AT&T iPhone 4 last summer, customers complained that holding the device in certain ways or touching it in specific spots lowered signal strength and dropped calls.
Experts, including Web, explained at the time that placing part of one's hand over a slot degraded performance by bridging the separate antennas, changing the length of the cellular antenna and thus its ability to receive and transmit.
The iPhone destined for Verizon has four such slots, one near the top, the other near the bottom on each side. The original iPhone 4 sported three slots, one on the top, and one low on each side.
Based on the number of slots and their symmetrical position, Webb speculated that the Verizon iPhone has two identical cellular antennas. Covering a slot on one side of the new iPhone may hamper reception, but the phone should still be able to receive and transmit properly as long as the other isn't similarly bridged by a finger or palm.
"That looks like it's a possibility," said Webb, who like everyone prior to Feb. 10 when Verizon's iPhone goes public , was taking an educated guess. "Apple might have done something clever here by scrambling to come up with a better solution, two cellular antennas."
Others have also said that Verizon iPhone has multiple cellular antennas.
The technology site AnandTech , which was among the first last year to quantify the signal loss of iPhone 4's "death grip," said that Verizon requires dual-receive antennas for devices that access its network.
AnandTech, however, claimed that the top of the Verizon iPhone -- the frame segment defined by the two slots at the top of either side -- was the second receive antenna.
On AT&T's iPhone, the top of the frame was split with a slot, one segment part of the cellular antenna, the other a section of the Wi-Fi, Bluetooth, and GPS antenna.
If the top of the Verizon iPhone is a second receive antenna, what happened to the one for Wi-Fi?
Webb thinks he knows.
"There's evidence that Apple moved the Wi-Fi antenna into the case, under the glass back," said Webb after poring over available photographs and looking at the some of the smartphone's testing documents published this week on the Federal Communications Commission (FCC) Web site.
One clue that the move was feasible is the lack of a SIM card slot; AT&T's model has one, but Verizon's does not.
"As soon as you get rid of the SIM card, you get a whole lot of real estate inside the phone," said Webb. "Enough to shove a Wi-Fi antenna behind the glass back."
By moving the Wi-Fi, Bluetooth and GPS antenna inside the iPhone, it freed space for Apple to craft two cellular antennas within the steel frame, Webb added.
Unlike journalists and bloggers who had brief hands-on time with the Verizon iPhone at the Tuesday launch event, Webb declined to speculate on how well the new antenna design will handle calls and data, or whether the "death grip" may return to haunt Apple.
"We'll see how it works next month, but I think the steps Apple took were all good," said Webb.
Gregg Keizer covers Microsoft, security issues, Apple, Web browsers and general technology breaking news for Computerworld. Follow Gregg on Twitter at @gkeizer , or subscribe to Gregg's RSS feed . His e-mail address is email@example.com .
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