Originally Posted by coolcat
It'd be a super easy fix that wouldn't affect the appearance of the phone one bit. They could just apply some clear type of coating to the antennas that will keep our hands from touching them and causing all this BS....Can't believe they didn't do it in the first place when one of their OWN techs voiced concern...
Unfortunately it's not quite that easy. For the signal loss due to de-tuning of the antenna, yes, some sort of coating would be part of a solution, though a coating over the gap between the two would actually act as a capacitor, which is not a block to RF (it is to dc), so that in itself would de-tune the antenna (you can actually use a capacitor in your antenna circuit to change it's resonant frequency and tune it in). I would imagine they could make some tweaks inside in conjunction to a coating which would alleviate that however. It's 10 years since I did any work on antennas and to be honest my memory is a bit rusty.
What a clear coating would not help is the attenuating effect of the proximity of your hand. The attenuating effect of your hand is nothing to do with whether or not there is an insulator between your hand and the antenna, more it is to do with the fact that there is something that is mostly water (remember, we're about 70% water) which will happily soak up RF energy and lower the received (and transmitted) signal. The only way around that is to move the antenna away from your hand, which the bumper will do a bit, and moving the antenna inside would do.
However, from what I've seen (and I admit, I don't have an iPhone 4 to play with, so I'm basing this off the videos I've seen), I suspect this problem is being caused almost entirely by de-tuning, and a coating, coupled with some internal tweaks would resolve it. I'm basing that on the idea that since a bumper does seem to solve the problem, and it only moves your hand a couple of mm away from the antenna, it's not really changing the attenuating effect of your hand, so the fact that it fixes the problem would point to de-tuning being the root cause).
That said, a clear coating is not exactly straightforward, given it will be going on an area of the phone that is handled/rubbed a lot, and would be sensitive to rubbing off. I'm not saying there is not such a coating out there, and there might be something really easy (I'm not a materials engineer), but I would think it's actually a bit of a challenge.