Researchers develop ground-penetrating 'Wi-Fi' tech with 100m range

ETRI researchers created an underground wireless networking system that can reach up to 100 meters below the surface.

The system uses magnetic induction to communicate with devices underground, avoiding the signal attenuation typical of radio-frequency methods.

Tests used a 0.9×0.9 m transmitter loop antenna and a small magnetic-field receiving sensor, sending data at 2 Kb/s using quadrature phase-shift keying.

Experiments were carried out in limestone bedrock, which blocks radio signals; the concept began in 2023 as a voltage-driven approach and later shifted to a current-driven magnetic induction method.

ETRI is considering smartphone implementation and the technology could help emergency services communicate with people underground.