iPhone 4G – ‘HD’ Antennas Found?
See the update at the bottom for the real deal, I was partly wrong about some of the antennas in iPhone 4, though I was indeed right about the connector locations for the bottom, and partly for the top.
I’ve been following the iPhone 4G/HD leak saga like a hawk, and until now I haven’t been able to really add anything to all that’s been said. However, today, Gizmodo published pictures of the inside of the iPhone 4G hardware they obtained. They didn’t talk about much other than the absurd number of screws (upwards of 30), battery size, packaging, and potential ease of replacement. In fact, their primary aim seems to have been locating “APPLE” markings on the few ribbon cables inside, rather than picking apart Apple’s hardware choices. No doubt disassembly was challenging, potentially explaining why there aren’t any photos of the iPhone with the “connect to iTunes” lock screen (broken after disassembly?).
They neglected to remove the EMI shields atop the interesting bits on the PCB, what I would’ve considered the biggest news about the device. So we still don’t know virtually anything about SoC, how much NAND flash there is onboard, RAM, the hugely important baseband (and whether this thing is potentially dual CDMA/GSM and UMTS for it to work on Verizon/Sprint alongside T-Mobile and AT&T), WiFi or Bluetooth choices (likely the same as the iPad, however), or anything else you’d expect to glean without those shields in place. In short, all the squares in this diagram from the iPhone 3GS are big question marks for the iPhone 4G. Still, we can make very good guesses about what the likely choices are.
However, being the RF-obsessed dude I am, I scrutinized the photos for some time looking for other interesting bits. I think I’ve found some interesting things.
First and foremost, I think that there are two discrete antenna assemblies in the phone. One at the top, one at the bottom (as you’d hold it in your hand).
Note that the phone in this picture has been rotated; the red circled area on the hardware is actually the bottom. Now, look at the two places I’ve marked with the white arrows. You can very clearly see a pigtail and standard radio connector on the top one, and a connector pad at the tip of the arrow at right. This is 100% certainly an antenna, and it’s also in the same region of the hardware (at the bottom) as the 3GS.
Above is what I’m talking about at 100% resolution.
Above shows the antenna before being removed, with the pigtail clearly connected to the mainboard PCB. We can make an educated guess that whatever is under the EMI shield next door is the baseband.
Now, compare and contrast to the iPhone 3GS’s ribbon/kapton antenna assembly:
And see it inside the black plastic holder (only the trailing ribbon connector is visible at bottom left):
If I’m not mistaken, the two connectors there are for discrete antennas inside, for cellular radio and WiFi/Bluetooth. I’m not infinitely familiar, but there only seems to be one antenna assembly in the 3GS at the bottom.
Now, on the iPhone 4G photos, there appears to possibly be a second possible antenna at the top.
I’ve labeled the connector that I can make out. Given the similar black packaging (possibly housing the flex PCB like in the 3GS), it seems likely this is another antenna.
I’ll leave you to speculate about why Apple might potentially want two discrete cellular antennas in their next generation phone…
After looking through the FCC OET internal photos of a huge number of other dual CDMA/UMTS design phones, all of which only require one antenna, I’m pretty sure the other top component is something less insidious. It’s entirely possible this is nothing more than a connector, some support structure, or perhaps maybe it is indeed an antenna, but for WiFi (N?). Whatever the case, I’m completely uncertain what this thing is, or if it’s part of the baseband. Obviously, the part at the bottom is an antenna, but the top part I’m more and more uncertain about.
We’ll see as time goes on and better pictures are made available what it is, but I’m not confident it’s an antenna anymore.
Of course, we now know the real deal with the iPhone 4. I was wrong about what the antennas were, but right about the connectors. Up at the top, if you scrutinize iFixit’s teardown, you can see a small gold pad right above a test junction for the WiFi/GPS/BT 2.4 GHz antenna. There’s a trace on the EMI shield which leads to a contact screw (gold, so it’s visible) leading directly to the antenna. So the connector for the 2.4 GHz antenna is up at the top near that seam.
For the UMTS/GSM antenna, the connector snakes across from the PCB to the left side of the phone facing up (facing down, it snakes to the right, like in this photo):
You can see the test point and connector at the left, the pigtail leading to the right across the EMI shield, and the gold screw which connects the whole deal to the aluminum antenna.
Of course, the interesting part is that this becomes the most active region of the antenna. It’s a monopole, rather than a dipole – in this configuration. The result is that for 1/4 wavelength, that part of the aluminum is very active at radiating RF. This is also the location your palm rests, interestingly.
I’m going to talk about the real deal on AnandTech shortly, so stay tuned…
It’s live here now: http://www.anandtech.com/show/3794/the-iphone-4-review/1