ok folks, time for a simple lesson in physics.
first off, any metallic case, be it aluminum, steel, titanium, or any alloy of these materials, is dense. all metals have dense molecular construction that gives it the properties they exhibit in hardness and tensile strength, some more than others. because of this, it also makes them great conductors for both heat and electricity. however, it also makes them all great shielding agents against radiation, of course the more dense the metal compound, the better… lead being one of the better metals for shielding from radiation.
now this brings about the topic for radio transmission, what makes your cell phone “wireless.” like any other form of radiation, these metallic compounds, depending on their density, will cause an attenuating effect of the desired radiation if the radiating device, in this case the antenna, is covered by a case made of these materials. it doesnt matter one bit if the metal comes into contact with the antenna or not; the signal will be reduced as it’s unable to pass through the shielding material.
therefore, ALL metallic cases will attenuate the signal on ALL cellphones. it’s simply due to the shielding effects of the metal compound of the case. in fact, even composite cases will affect the signal, although to a much lesser degree to the point of being nearly unnoticeable. yes, some of the most expensive cases are machined from aluminum or titanium and they look awesome in some cases, but they will cause signal attenuation that is unpreventable no matter how it’s designed. the only way to prevent this is to ground the case into the antenna, therefore acting as an extension of the antenna and extending radiation itself. because most cell phones have an internally placed antenna, this is impossible. despite the advertising of the iPhone claiming integration of the antenna into the structural support exposed as a steel band around the perimeter of the device, the radiator is still within the body of the device and simple contact between a metallic case and the midframe will NOT negate the issue of signal shielding, much less improve signal radiation. in fact, since you’re now shielding the primary radiating component, you’re going to experience degradation of the signal.
this is basic physics and is undeniable. dont blame the designers of these cases for anything other than designing something that works to reduce signal performance. this is something everyone should already know and have taken into account before their purchase of a metallic case. any manufacturer who claims to have worked around, solved, or even improves performance is trading on fraudulent claims. ignorance is no excuse.
JetCity Ninja 
Sorry, didn’t like this post. You sit there saying “it’s simple physics, everyone should know this.” If it’s such common sense no need to write this post. At the end you pretty much call us ignorant.
Well buddy, here is some “Common sense” chemistry.
1. Metals aren’t “metal compounds” they are “elemental compounds.”
2. You claim the issue is “the molecular construction.” Yet you also stated that Pb is better at shielding(compared to Al). Pb & Al have the same crystalline structure. So that has nothing to do with it.
It’s just common sense right?
I confirmed that an aluminum case was affecting my Galaxy S4 reception. It is a cheap case, bought from Big Lots, that has aluminum in its design. I had noticed that phone performance had degraded since I started using it. With the case, the phone only managed 1 bar. Without it, the bars went up to 4. The data reception also greatly improved leaving me somewhat ashamed of my somewhat terse phone calls to TMobile in regards to their service.
We’ll explained , I was facing the problem will all al casing
I stumbled upon this page looking at cellphones signal strength, very useful knowledge and well said Oakie.
i have been reading random articles about trying to figure out why my iphone 4s’s wifi has been disconnecting intermittently… and then i get to this post. i read the whole damn thing, including the comments. i laughed out loud several times. priceless. and you sound like you know what you are talking about which makes it even better. i am going to see if there are any new posts that strike my fancy. nice work.
I frequently have no choice but to keep my phone in my pocket for long periods of time. Doing so exposes me to constant radiation. What if I put a layer of aluminum foil in my pocket between me and the phone? Would that help reduce the flow of radiation into my body? Would that hurt the phone? Thanks.
not sure if you’re serious, but I’ll respond factually anyways.
1. you’d have a foil covered phone.
2. no. cellphones are transceivers. you’re exposed to far more radiation from cell towers, TV & radio transmissions, solar, etc. than a digital phone in your pocket. you should be more concerned about melanoma from sun exposure.
3. might scratch the anodized surfaces and may interfere with reception, especially in a location with poor coverage.
I am serious. The iPhone instruction manual specifically states that you shouldn’t carry the phone in your pocket due to radiation exposure. So if I’m doing it all day, I’m putting myself at risk, eh? I don’t care about lost reception while the phone is in my pocket. But I do care about my reproductive organs. I could avoid scratching by putting rubber between the foil and the phone. But will the foil harm the phone’s circuitry?
foil is not going to harm your device’s circuitry in any way unless you’re stuffing aluminum into the charging port or something else of the sort.
the amount of radiation emitted from a current, digital cellphone is far below the threshold of harm as long as it is working properly. that printed warning is due to an old law created before cellphone technology advanced from analog to digital Tx/Rx; analog cellular devices emitted very high levels of radiation that was found to contribute to development of brain tumors under lab conditions and some real-world occurrences.
today’s digital phones emit far less radiation, but the law still requires a printed warning on every cellular phone sold. the fact is that you will receive a far more powerful dose of radiation by standing near a cellular transmission tower for a few minutes than you’d get from your phone alone, in your trouser pocket, for a week.
i encourage you to read about digital cellular radiation, emissions data for your specific device, and peer reviewed studies done for the FCC and published in journals like JAMA to get a better understanding of just how much radiation you’re exposed to.
if you’re still concerned after researching the facts, you can start by putting your phone in a shoulder bag instead of on your person. there are also shielded wallets you can buy to carry your phone in; start by searching for “RFID shielded pouch.” a shielded pouch or wallet will be far more effective at blocking emissions if properly constructed but the result is that you won’t receive calls or texts since transmission signals won’t reach your phone. if that’s not a problem, you can save yourself $50 by turning off your phone or activating “airplane mode” so it ceases to emit any radiation.
Thanks again.
I have a weak signal in my house, partly because there are weak cell signals in my area and maybe the metal roof doesn’t help either. I do get some weak signal in specific locations in the house. But I’ve also noticed that putting the cell phone inside an aluminum kitchen pot, strengthens the signal. Usually I go from one bar to two, plus I’ve even gotten 3G and 4G, something I’ve never seen before in my house. Could it be that the shape of the pot acts as a reflector so th signal can enter the top but can’t escape the sides or bottom?
the shape of the pot is acting like a passive receiver, akin to a satellite dish that refocuses stray signal into a focused beam for increased reception.
otherwise, a home with a metal roof and solid walls acts like a faraday cage, reflecting signals away from the interior.
glass radiates rf radiation and you can get better reception by hanging out near a window.
Thanks. I definitely only get signal when close to certain windows. It’s still very weak. Put it in the pot and I can actually use the phone sometimes.
What are your thoughts about running a small wire from the antenna in the phone, out a speaker hole at the bottom of the phone, and connect it to the aluminum case? Would it turn the case into an antenna?
yes, BUT…
different bands use different antennas. it’s why devices like the iPhone have plastic spacers to divide up the housing. unless the case is also divided up so different sections can accommodate the different signals, it will simply fail in the same way the original iPhone 4 would fail when holding it “the wrong way.” that was the result of one’s hand bridging dissimilar antennas, eroding the signal.
Makes sense. I have the iPhone 5s, have you heard of doing that? Maybe connecting the different wires to a sticky antenna booster that can be placed in different locations on the back of the aluminum case, so they don’t ground out each other?
just don’t block the glass portions of the rear face. glass is RF transparent and why the iPhone 5/5s has it on the top and bottom. the upper and lower edges of the housing are also separated from the center to use those sections of aluminum as antennae.
unless your case design covers these areas completely, adding passive radiators will do little to increase reception since reception isn’t being crippled in the first place. using an RF transparent material is superior in most design exercises anyways due to it’s resilience in impact protection. most metal cases, I have found, provide little to no actual impact protection due to lack of memory, i.e. the metal doesn’t return to it’s original form after impact.
Can I do the wire from the antenna to the aluminum case where the screw goes…….. on a Samsung galaxy mega 6.3? I saw a assembly video and the antenna looks like a small metal rod next to the battery.. I just need to know if I can coil a small cable from that antenna to the case..? if it will work? If it wont damage the phone or antenna? Your opinion is very much appreciated…… thank you…….
Well said