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Pocket-sized antenna excels where traditional radio waves fall short

By Shawn Knight · 8 replies
Apr 12, 2019
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  1. Researchers at the Department of Energy’s SLAC National Accelerator Laboratory have developed a pocket-sized antenna that could enable mobile communications in situations or environments where traditional radio waves aren’t effective.

    The device emits very low frequency (VLF) radiation with wavelengths of tens to hundreds of miles. The waves are able to travel long distances and can penetrate materials that would otherwise block conventional radio waves such as under water or ground.

    The device utilizes the piezoelectric effect to generate VLF radiation, converting mechanical stress to a build-up of electrical charge.

    “The researchers used a rod-shaped crystal of a piezoelectric material, lithium niobate, as their antenna. When they applied an oscillating electric voltage to the rod it vibrated, alternately shrinking and expanding, and this mechanical stress triggered an oscillating electric current whose electromagnetic energy then got emitted as VLF radiation.”

    Today’s most powerful VLF technology requires massive emitters but the new antenna is quite compact at just four inches tall. As such, it could be a valuable tool for search and rescue teams and among the military.

    The team’s full write-up can be found in today’s Nature Communications.

    Permalink to story.

     
  2. jobeard

    jobeard TS Ambassador Posts: 12,874   +1,526

    What's old comes back as new. Meet LORAN:

    LORAN, short for long range navigation,[a] was a hyperbolic radio navigation system developed in the United States during World War II. It was similar to the UK's Gee system but operated at lower frequencies in order to provide an improved range up to 1,500 miles (2,400 km) with an accuracy of tens of miles. It was first used for ship convoys crossing the Atlantic Ocean, and then by long-range patrol aircraft, but found its main use on the ships and aircraft operating in the Pacific theatre.​

    See the wiki here.
     
    CloudCatcher, p51d007 and Uncle Al like this.
  3. ferrellsl

    ferrellsl TS Enthusiast Posts: 25   +24

    This system has nothing in common with LORAN. It is not a beacon system used for triangulation/navigation. It's a data transmission system similar to the ELF systems used on submarines for data transmission.
     
    mbrowne5061 likes this.
  4. Godel

    Godel TS Addict Posts: 173   +88

    Not mentioned in article, data rate was 100 bits per second and I imagine receive antenna still had to be huge.
     
  5. jobeard

    jobeard TS Ambassador Posts: 12,874   +1,526

    @ferrellsl
    If you were looking for similar or identical functionality, then you are correct -- contrats.

    Understanding that all progress stands upon the shoulders of those that have come before however, the relationship is the properties of low frequency wave propagation and the fact that low Fq creates long wave lengths which have great penetration ability. This is why 2.4Ghz penetrates better the 5Ghz wifi.
     
  6. ferrellsl

    ferrellsl TS Enthusiast Posts: 25   +24

    Again, this article AND this thread are about data transmission using VLF/ELF frequencies and very small antennas, not about LORAN and not about Wi-Fi propagation or Wi-Fi data transmission. I also am not in need of any radio theory classes with regard to wave propagation or which frequency bands have better penetration capabilities. I'm quite familiar with both having been deeply involved in the US DoD's communications fielding efforts and understand quite well the properties of the radio radio spectrum whether it's ELF or SHF or the bands in-between.
     
  7. jobeard

    jobeard TS Ambassador Posts: 12,874   +1,526

    Then I am shocked you can't make the connection of an unmodulated signal to one with intelligence imposed upon it. I did not assert (but perhaps was easily construed) there was an equivalence to Loran -- that was not intended.

    Guess you're equally familiar with CW, AM, FM, SSB, DSB, Telemetry systems and frequency hopping.

    I just don't limit myself to the preexisting solutions as the sole domain of possibilities.

    Thank you for your inputs however.
     
  8. jobeard

    jobeard TS Ambassador Posts: 12,874   +1,526

    Well, normally we need to optimize the transmitting antennae (impedance and wave length) and any old piece of wire is sufficient for reception.
     
  9. ferrellsl

    ferrellsl TS Enthusiast Posts: 25   +24

    QUOTE: Then I am shocked you can't make the connection of an unmodulated signal to one with intelligence imposed upon it. I did not assert (but perhaps was easily construed) there was an equivalence to Loran -- that was not intended.

    Guess you're equally familiar with CW, AM, FM, SSB, DSB, Telemetry systems and frequency hopping.

    I just don't limit myself to the preexisting solutions as the sole domain of possibilities.

    Thank you for your inputs however.

    -----------------------------

    Where do you take the huge leap that I can't make the connection between signals and modulating data on them? That was the very essence of the article (which you completely missed) so why would I need to re-state the obvious? And you DID assert it was a re-emergence of old LORAN beacon/navigation technology unless you've gone back and edited your posts to state otherwise. Thank you for your false assumptions about the readership of TechSpot articles as well as my education and experience in the world of signals. No need to be so condescending or insulting just because you've been corrected. It wasn't my intention to bruise your fragile ego.
     

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