Apple's antenna guru reportedly warned execs about iPhone 4 design

The steel sideband is actually two antennas, one for cellular (along the right side, bottom and the left corner) and one for Wi-Fi and Bluetooth (along the left side, top and right corner)
  • John Cox (Network World)
  • 16 July, 2010 08:42

Warnings by Apple's top antenna expert that the iPhone 4 design could clobber signal strength and lead to dropped calls were ignored by the company's top executives, according to a Bloomberg News story today.

In addition, at least one of Apple's carrier partners expressed concerns about the new design, which moved the phone's antennas to the outside, integrated with a stainless steel band around the edge of the device. The reporters cite two sources in their story, both identified as a "person familiar with the situation" and both requesting anonymity.

Poll: What will Steve Jobs say about iPhone 4 antenna tomorrow?

Apple has called a press conference about the iPhone 4 for Friday morning at its Cupertino, Calif., headquarters. Speculation is that the company will address the complaints of some users regarding weakened reception in the new iPhone.

It can't come soon enough for Apple: the snafu has entered the popular imagination. On Tuesday night, David Letterman offered his "Top 10 signs you've purchased a bad iPhone".

According to Bloomberg's sources, in 2009, Ruben Caballero, listed on Linked-In as senior director iPhone/iPod at Apple, told senior-level managers that the exterior placement could hurt reception. But the proposed design was favored anyway, apparently because it allowed for a slightly thinner, narrower and lighter phone.

According to Bloomberg News, the iPhone design team under Jonathan Ive presented Steve Jobs and other top executives several designs. The managers finally decided on the exterior antenna design. According to one of Bloomberg's sources, Caballero voiced concern in several early planning meetings, warning about the possibility of dropped calls, and calling attention to the seriousness of the engineering challenged posed by the exterior placement.

The steel sideband is actually two antennas, one for cellular (along the right side, bottom and the left corner) and one for Wi-Fi and Bluetooth (along the left side, top and right corner).

The reasons for the degraded reception are well known to antenna experts. All cell phones experience signal attenuation or loss when held next to the head: that's because the human body, in RF terms, is a large "bag" of salty water, which tends to block some of the radio signal. But in the iPhone's case, the hand actually touches the antenna, and in most cases bridges what are intended as two separate antennas.

The result is detuning, making it harder to squirt energy into the desired cellular frequency band, as Spencer Webb, president of antenna design firm AntennaSys has written. When the original base station signal is weak, the additional deturning effect can dramatically lower data rates, though many users never notice this.

Apple has fumbled in its response to the complaints, which began almost as soon as the phone went on sale. In one statement, the company noted, correctly, that all cell phones experience signal attenuation. It recommended holding the phone in ways to mitigate that loss or urged users to buy a rubberized "bumper" -- essentially a thick elastic band that fits around the entire phone insulating the steel band from contact with the body. Apple's bumpers are priced at US$29.

Anecdotal evidence, as well as more rigorous tests both by Consumer Reports and Spencer Webb, confirm that using a bumper dramatically improves the signal.

In the same statement, Apple also said it was "stunned" to learn that the cellular signal indicator -- the "5 bars" icon -- was inaccurate, and promised that a software update would make it more accurate and that this update would solve the reception problem. Although it's true that the bars on all cell phones are almost useless in terms of real data about signal strength, Apple's response was sharply criticized as having nothing to do with the real problem of antenna detuning.

Despite the retail success of the iPhone 4, the company's stock price has been falling, since before the phone was released in late June. The per share price was at a 30-day high of almost $279 on June 18, dropping to $244 on July 2, and now hovers around $251.

Consumer Reports came to a similar conclusion after its own tests (though these tests have been heavily criticized by antenna experts, including Webb) and refused to recommend buying the iPhone 4.

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