iPhone 4 external antenna causing dropped calls?

There was no shortage of applause when Steve Jobs revealed that the iPhone 4's slender build was in no small part down to shifting the UMTS, GSM, Bluetooth, WiFi and GPS antennas to the outer stainless steel rim of the smartphone, but that decision may be coming back to haunt the company.  As we reported yesterday, some new users were claiming that holding their iPhone 4 at certain points led to dropped calls and zero bars of signal strength on-screen.  If anything, the complaints are getting louder – especially from those who generally hold their phone in their left hand – and stories as to what might be causing the issue are being to emerge.

Over at ZDNet Rupert Goodwins has put together a decent explanation – which doesn't require a degree in engineering – that explains why the issue might be happening.  Basically, to improve reception Apple chose to put their aerials on the outside, and now they're subject to the conductive interference of users' hands.

"Now, it is possible to have automatic matching circuits that compensate for this effect but at the frequencies used in the iPhone, these would need to be clever indeed — most likely using MEMS — and I've seen no hints in the literature that any such technology is close to commercialisation. If Apple has this, then it will be genuine innovation that it simply must have patented" Rupert Goodwins, ZDNet

Engadget are observing the same problem with their iPhone 4 handsets (which also show the yellow banding other owners have reported) and the general point of complaint appears to be the bottom left-hand corner.  That's where two antennas meet, and lending weight to the argument is that adding a rubber Bumper shell – which covers the join – fixes the problem.  No word from Apple themselves about the issue as yet.