Researchers from the Electronics and Telecommunications Research Institute (ETRI) announced their success, highlighting the successful use of a one-meter diameter transmitting antenna and a miniature receiving antenna, both of which allow the transmission and reception of audio signals deep underground. In particular, this technology has proven its effectiveness in transmitting signals at a depth of 40 meters below the surface of the earth and also at a depth of 40 meters underwater.

An important issue has been resolved

One of the main problems of underground communications signal fadingThis made wireless communication almost impossible in the harsh conditions of underground mines. But ETRI scientists skillfully used the unique properties of magnetic fields in these conditions to overcome this problem. The result was a remarkable ability to reliably transmit signals beneath the earth’s surface.

These antennas act as access points that seamlessly connect ground-based base stations to underground devices. This new connection means people working underground can now call aboveground from their mobile phones.

Field tests

To achieve these results, the scientists used a narrow low-frequency band of 20 kHz, which is significantly different from the MHz and GHz bands commonly used in wireless communications. This choice of frequency was strategic and aimed to minimize signal loss in underground conditions and to match the size of the antennas. The audio signal transmission rate was kept at 4 Kbit/s.

Besides applications in underground mines, this magnetic underground communication technology has been successfully tested at a depth of 40 meters under the freshwater column, proving its versatility and adaptability to a variety of underground and underwater conditions.