A group of South Korean researchers at the Electronics and Telecommunications Research Institute (ETRI) has successfully created a new underground wireless networking technology capable of penetrating as much as 100 meters below the Earth's surface. As published in the IEEE Xplore journal, this new method takes advantage of magnetic induction to provide clear communication with devices underground and avoids signal attenuation and degradation that would occur with traditional radio-frequency methods.
The test equipment consists of a (relatively) small transmitter loop antenna measuring 0.9 by 0.9 square meters and a small magnetic field receiving sensor, all connected to a wireless communication system using quadrature phase-shift keying modulation to transmit data, albeit at an incredibly limited 2 Kb/s. The testing was conducted in a limestone bedrock environment known for blocking radio signals effectively.
The basic idea for this technology was originally developed in 2023, when the researchers first discovered that ground-penetrating wireless communication was possible with a voltage-driven method. To get around the limits of the prior version of the tech, the researchers developed a current-driven method of using magnetic induction to transmit wireless signals through the earth using low radio frequencies. At first, the researchers were able to achieve 40m of underground range, but with the shift to magnetic induction, the researchers were able to expand the range to 100m.
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Ground-penetrating communication methods, known as Through-The-Earth communications systems, already exist. But these devices don't take advantage of magnetic fields and instead rely on extremely high transmission power to achieve the range necessary to be useful. With this new type of magnetic field communication that these researchers have developed, ground-penetrating communication could potentially be incorporated into smaller devices with lower power and broader applications.
The ETRI is reportedly already looking to implement this technology into smartphones. Having this technology in more portable devices would expand the accessibility of underground wireless communication to virtually all industries and individuals who work or engage in recreation in tunnels and caves. Most importantly, this tech could potentially allow emergency services to communicate with individuals lost or stuck underground. The ETRI has also reportedly discussed the possibility of this technology being useful for offshore drilling and national defense.
Let somebody invent wireless HDMI which reliably goes through just the usual concrete or wooden walls from one side of standard offices and homes to the other. Only fiber optic cable is working for that now.
Sounds like the same technique as used in geophysical surveying, but instead of collecting the backscatter from the pulses they are just picked up at the far end.
