iPhone 4 uses stainless steel frame as antenna for WiFi, GPS, Bluetooth, GSM/3G (Badass)

iPhone 4 uses its stainless steel frame as a radio antenna for cellular, GPS, WiFi, Bluetooth functions to save space.

One of the juicier little bits of info about the iPhone 4 that Steve Jobs dropped today was that the iPhone 4 uses its stainless steel frame as cellular and WiFi antenna, much like the way the iPad was confirmed to be using its LCD frame as the antenna for its WiFi and cellular radios. You may have missed the mention of the frame-as-antenna during the keynote, but we thought it was a seriously cool feature that will push smartphone innovation to yet another level. So, what’s the big deal?

Well, it all has to do with how slim the iPhone 4 is. The new Apple smartphone is just 9.3mm thin. That’s as thin or thinner than a No. 2 pencil. In order to get the iPhone 4 that thin, though, Apple needed to find innovative ways to shave of precious millimeters from the device’s waistline. The microSIM that everyone loves so much was one way to save space. The other, decidedly cooler way Apple saved space within their smartphone was to turn the frame into a radio antenna. Rather than take up volume within the phone’s body to house GSM/3G (UMTS), WiFi, Bluetooth, and GPS antennas, Apple decided to turn the already-there stainless steel frame lining the sides of the device into a couple giant antennas (see pics above). That’s cool.

What does this mean for you? Well, you can expect to see future smartphones becoming thinner and thinner as they incorporate radio antennas into the body of the phone itself. You can also expect the new iPhone 4 to have superior cellular reception, because the antenna is essentially located on the outer surface of the handset. That’s going to be a big plus for iPhone hopefuls on the fringes of their cellular network.

All in all, the iPhone 4 is looking like it’ll be another innovator in the smartphone space. Did you expect any different?

  • a1by

    While I'd expect the signal quality to be improved, let's see real world performance first

    • Bradley Green

      Results are in. Holding the phone in your hand kills the signal if you bridge the antennas with your hand.

  • Jeff

    Hope that will improve GPS signal, cause it's really bad with the 3GS

  • Mike

    Need an antenna engineer to comment on this… with the antenna on the edge of the phone, isn't it going to be covered up by the users hand? Doesn't this make for worse antenna performance?

    • RadioGuru

      Depending on how the antenna is "loaded", the hand effect will impact the antenna "impedance" and create distortion in the radiating pattern. Furthermore, it seems that RX diversity is not supported, which is a key feature next generation smartphones shall have.
      Also, I wonder about polarization performance and its impact in mobile positioning for high speed packet data….we shall wait and see real life results…

      • Alessandro


        I am with mike, I don't like to be part of the radiation system. Thruth is that in this case you are not just exposed to a relatively strong EM field, but RF energy will flow into your body.
        Sorry, I don't feel this any clever, and honestly potentially dangerous.


      • Patty

        How could this frame have been "loaded" differently to totally avoid any problems?

  • worried

    I am worried about skin cancer. Direct antenna radiation on the skin is a big health no-no.

    • Filipe

      i know that's what i was thinking when i saw the keynote… you're physically touching not only an antenna but TWO powerful antennas o_o isn't that dangerous amounts of radiation?? (i still want this phone btw lol)

  • Erick

    good thing!!! now is gonna burn our brain directly 2W of RF energy 🙁

  • worried

    no noi, not the brain, I'm talking about SKIN cancer.

  • rmm

    The GPS antenna is completely BS. GPS requires a circularly antenna. The frame would give a linear polarization.

  • RF technician

    anytime you change the way the signal propagates such as having a free and open air space around the antenna vs holding it with your hands changes the way the signal radiates from the antenna thus completely hosing tx and rx characteristics. Its going to been even worse than before.

  • sean

    Any time you grip the two legs of a dipole antenna with a salty sweaty hand, you effectively short it out. WTH?

    Definitely were no RF engineers involved in the development process on this one…

  • Republic 71

    cool…so i can get a brain tumor even faster now. sweet!

  • JJ

    Funny how this “article” it’s a complete fail, praising a trait that was the biggest fail in iPhone 4

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