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Researchers Create 'Spray-On' 2D Antennas (phys.org)

In a study published in Science Advances, researchers in Drexel's College of Engineering describe a method for spraying invisibly thin antennas, made from a type of two-dimensional, metallic material called MXene, that perform as well as those being used in mobile devices, wireless routers and portable transducers. Phys.Org reports: The researchers, from the College's Department of Materials Science and Engineering, report that the MXene titanium carbide can be dissolved in water to create an ink or paint. The exceptional conductivity of the material enables it to transmit and direct radio waves, even when it's applied in a very thin coating. Preserving transmission quality in a form this thin is significant because it would allow antennas to easily be embedded -- literally, sprayed on -- in a wide variety of objects and surfaces without adding additional weight or circuitry or requiring a certain level of rigidity.

Initial testing of the sprayed antennas suggest that they can perform with the same range of quality as current antennas, which are made from familiar metals, like gold, silver, copper and aluminum, but are much thicker than MXene antennas. Making antennas smaller and lighter has long been a goal of materials scientists and electrical engineers, so this discovery is a sizable step forward both in terms of reducing their footprint as well as broadening their application.

42 comments

  1. You scratched it! by Anonymous Coward · · Score: 2, Funny

    You scratched my antenna! How am I supposed to look at cat photos now?

    1. Re:You scratched it! by PopeRatzzo · · Score: 2
      Worse yet, a "2D antenna" is going to have "2 problems" which make it impractical:

      • 1. The material is not a perfect conductor. As such, putting, oh, I don't know, a nanowatt (just making up numbers) will melt the antenna.
        2. The material is not a perfect conductor. Lossy materials cause lower gain on the receive end.

      Food for thought. Yes, I read the article.

    2. Re:You scratched it! by Anonymous Coward · · Score: 0

      This is actually NOT a "2d" antenna! It has some (very small) thickness, so its 3 dimensional. To my knowledge there are no "2d" objects...that is objects that have width and length, but no depth.

    3. Re:You scratched it! by LazarusQLong · · Score: 1

      one could spray it on in heavier concentrations, cover it with a protective coating, etc...being able to spray an antenna on, vice build an antenna then mount it is a big deal. Protective coatings are not unknown.

      --
      "Governments have been dominated by the corporate entities and citizens have ceased to matter in public policy" true in
  2. Thinner, but not smaller by Ozoner · · Score: 2

    This might make thinner antennas, but they won't be any smaller.

    They will still need a plastic support structure, will still need to be the same physical wavelength, and will still need to be mounted away from other metal.

    Sadly, it won't change the laws of physics.

    1. Re:Thinner, but not smaller by Anonymous Coward · · Score: 0

      The size of the antennas is determined by the wavelength, you get smaller antennas by increasing frequency.

      Where's Mr. Lev?

    2. Re: Thinner, but not smaller by Anonymous Coward · · Score: 0

      Funny, the one in my smartphone works fine despite your claims.

    3. Re:Thinner, but not smaller by SeaFox · · Score: 2

      They will still need a plastic support structure, will still need to be the same physical wavelength, and will still need to be mounted away from other metal.

      Imagine painting an antenna onto the support structure for the roof of a building, and then overlaying non-metallic roofing material on top of it, or painting over it on the inside.

    4. Re:Thinner, but not smaller by beheaderaswp · · Score: 4, Interesting

      This might make thinner antennas, but they won't be any smaller.

      They will still need a plastic support structure, will still need to be the same physical wavelength, and will still need to be mounted away from other metal.

      Sadly, it won't change the laws of physics.

      You got that right.... Though electrical length can be fudged using Mandelbrot forms. Though it's still not the most efficient antenna.

      Most antennas in cell phones are considered "efficient dummy loads". Ever since they went internal there are all kinds of polarization/gain issues. At least with the old semi-vertically polarized antennas you didn't drop 20db of gain by turning your head.

      And you are right... spray paint an antenna onto a piece of metal... and the metal will couple distorting the radiation pattern.

      The whole technology is rife with pitfalls. But some MBA will try and make it work leading to more crappy products...

      --
      Another consultant who stuck it out.

      "We are the Priests, of the Temples of Syrinx..."
    5. Re:Thinner, but not smaller by religionofpeas · · Score: 1

      If you're going to put an antenna on a roof, there's nothing wrong with a conventional one.

      I'm guessing this technique is most useful for portable devices, where every penny counts. Spray the antenna on the inside of the plastic case.

    6. Re: Thinner, but not smaller by Anonymous Coward · · Score: 0

      Not quite true : since it is a 2D material it is inherently flexible. Hence you can definetly bend it.
        This would allow for say, connected fabrics for instance (imagine a shirt measuring your vitals and sending a message automatically to your GP if you have a problem).
      As of smartphones, there is a lot of lost space as of now : all these little corners and lost space can be used as support. Sure you still need the same length of antenna to catch a given frequency but you can now but it on surfaces that were unreachable before

    7. Re:Thinner, but not smaller by Ozoner · · Score: 1

      This only requires that you run a relatively thin wire.

      And if you are going to paint over it, it doesn't even need to be thin.

      FWIW, Hams have been using "invisible" stealth antennas since day one.

      And invisible antennas have been printed on car windscreens for years

    8. Re:Thinner, but not smaller by Anonymous Coward · · Score: 0

      "spray paint an antenna onto a piece of metal... and the metal will couple distorting the radiation pattern."

      Maybe that's a bug, not a feature. Think "spray-on RFID" since each antenna will be or can be made unique.

    9. Re:Thinner, but not smaller by LazarusQLong · · Score: 1

      I see you have not heard of fractal antennas also known as a variation on space filling antennas. https://en.wikipedia.org/wiki/...

      --
      "Governments have been dominated by the corporate entities and citizens have ceased to matter in public policy" true in
    10. Re:Thinner, but not smaller by LazarusQLong · · Score: 1

      how about we stop being simplistic in our thinking? Imagine I have a metalic substrate, I spray a 4 mm coating of urethane to it, then I my antenna over that after the urethane has dried. Now I have an antenna with a backplane 'distorting'; the beam in one direction, or one could say, attenuating the incoming signals from one direction. Would this have value? Depends on my use case. Imagine instead I use an expanding foam as my barrier rather than simple urethane? Now I can develope a larger thickness if I so desire. In both cases I mention above one can create much cheaper antennas in a conformal mode.

      --
      "Governments have been dominated by the corporate entities and citizens have ceased to matter in public policy" true in
    11. Re:Thinner, but not smaller by beheaderaswp · · Score: 1

      In both cases I mention above one can create much cheaper antennas in a conformal mode.

      And they won't work....

      You can't slap a metal "backplane" on a sprayed on 2d antenna and get anything other than a ridiculous standing wave ratio. Also, the electronics used in a conformal antennas to create directional beamforming are prohibitively expensive and even classified. "Backplanes" do not create directionality.

      The next time you Wikipedia dive for a comment- make sure you read the whole article.

      --
      Another consultant who stuck it out.

      "We are the Priests, of the Temples of Syrinx..."
  3. If I paint my home with it... by Anonymous Coward · · Score: 0

    will I finally get free wifi ?

    1. Re:If I paint my home with it... by Anonymous Coward · · Score: 0

      It's invisible... spray it on a friends motherboard.

  4. Ringworld Throne by DougDot · · Score: 4, Interesting

    This spray-on antenna technology first appeared in Larry Niven's Ringworld Throne, published in 1996.

    1. Re:Ringworld Throne by Anonymous Coward · · Score: 0

      I love science fiction's ability to introduce ideas that inspire people to make them into reality, but electrically conductive paint sprays have been around since the at least as far back as the 1950s. Larry Niven didn't invent the idea.

      This article is about a far more advanced and efficient version of what was produced then, but it's still the same concept.

    2. Re:Ringworld Throne by Anonymous Coward · · Score: 0

      What's an antenna?

    3. Re:Ringworld Throne by Rick+Schumann · · Score: 1

      Intimately familiar with Larry Niven's works. I think you're thinking of Puppeteer technology, that allowed entire audio-visual surveillance and communications devices to be literally sprayed onto surfaces; it was described as looking quite a bit like a spiderweb.

  5. A link that works by Procrasti · · Score: 2
    1. Re:A link that works by Anonymous Coward · · Score: 0

      Thank you!

  6. Re:This isn't new!! by Anonymous Coward · · Score: 0

    You trolltards make me laugh!

  7. Missing the primary use... by Anonymous Coward · · Score: 0

    And why the compound itself isn't documented:
    This will be used as a modern equivalent of the old espionage antennas.

    Having something invisibly thin you can stencil/spray out in the field and wire up to an espionage device, before coating the whole thing in a layer of paint will be a huge boon to whatever government/ngos have access to it.

  8. How to do you connect to it? by viperidaenz · · Score: 1

    You need to spray it on something, then connect a wire to it. Why not use the wire for the antenna?
    Like a PCB antenna, which is only 35um thick copper.

    If you want something thin and transparent, why not use ITO? It has similar resistivity to titanium carbide.
    Alternatively if this is cheaper than ITO, why not use it for LCD manufacturing?

    1. Re: How to do you connect to it? by Anonymous Coward · · Score: 0

      35um thick is actually pretty thick in the electronics realm. So it's like your are optimizing everything to have more space (=more room for storage device/computation power) and in the middle of it you have a giant mammoth antenna. Plus in terms of production cost, this new solution is probably cost effective since, contrary to your 35um wire antenna it doesn't require multiple stages of masking and etching to shape it accordingly : it is a bloody paint !

    2. Re: How to do you connect to it? by Ozoner · · Score: 1

      > and in the middle of it you have a giant mammoth antenna

      But this doesn't make it smaller or more compact.

      It still needs the same wavelength and the same spacing from nearby components.

  9. The link seems to have gone bad by I+kan+Spl · · Score: 1

    The second link in the summary "describe a method for spraying invisibly thin antennas" seems to go to an article titled "Facebook stops sending staff to help political campaigns". Was this link changed when being posted?

    --
    My UID is prime and so is this number: 09 F9 11 02 9D 74 E3 5B D8 41 56 C5 63 56 88 C0.
  10. WOW! Conductive paint! by Anonymous Coward · · Score: 1

    We don't have that where I come from.

  11. An antenna that can dissolve in water by Anonymous Coward · · Score: 0

    What could go wrong?

  12. Real antennas can be adjusted by Anonymous Coward · · Score: 0

    The same problems occur with these spray on antennas as any fixed antenna. You cannot adjust their angle for reception without adjusting the whole device. Yo u also face a problem of durability with such a product as a spray on material. Or corrosion affecting conductivity.

  13. Faraday cage in can by Anonymous Coward · · Score: 0

    I am not sure how valuable it will be as an antenna, but it could have serious potential as a spray on shield technology

  14. Very limited capability by mysidia · · Score: 1

    sprayed on? I imagine this cannot transmit or receive very much RF power.... A few milliwatts, perhaps. Not going to be able to receive a weak VHF/UHF signal or transmit at 5 or 10 Watts, comparable to a portable radio.

  15. We used to do this in the '80's by Anonymous Coward · · Score: 0

    As part of a research/development contract we used spray-on conductive paint designed for RF shielding to create antennas. This was a shortcut to building traditionally solid metal antennas and was eventually designed into the devices we were developing. The only real problem was that when the substrate flexed, the paint cracked and the antenna became useless. Despite our progress in advancing state of the art, the contract was cancelled and given to a huge aerospace company which used more traditional and costlier designs.

  16. Not exactly a new idea by Rick+Schumann · · Score: 1

    I don't think this is a new or ground-breaking development, considering that we've had the ability to draw conductors with a pen for quite some time now. Not particularly cheap, and tricky to solder to or otherwise connect to, but you could draw quite a few antennas with it. I'd bet good money I could, for instance, draw an HDTV antenna on a piece of cardboard with this, and it'd have decent gain. The 300-to-75-ohm balun would be a challenge, though, probably have to just buy one of those. Now, imagine a special print cartridge for an inkjet printer, or special toner for a laser printer, or a plotter pen. Just design the antenna you want in CAD then print it straight onto whatever.