Research on Ultra-Low-Frequency Communication Based on the Rotating Shutter Antenna

Abstract

This paper proposes a rotating shutter antenna that can directly generate 2FSK signals in the ULF band and it is expected to be used as the transmitter for magnetic induction (MI) underground communication systems. The antenna was modeled using ANSYS Maxwell and the magnetic field distribution was simulated. The results show that the interaction between the high-permeability shutter and the mutual cancellation of magnets decreased the transmitting magnetic moment of the antenna. A prototype antenna was manufactured and the time and frequency properties of the measured Bz field were the same as the simulated results, while the magnitude of the measured signal was larger. The propagation characteristics of the antenna in air–soil–rock were simulated using FEKO and the results show that the signal strength was greater than 1 fT at a depth of 450 m from the antenna whose magnetic moment as 1 Am2. The relationship between different magnetic components and azimuth could be used to enhance the signal strength. The formula of the Bz field was derived using the measured magnitude versus distance and the path loss was also analyzed. Finally, the 2FSK modulation property of the antenna was verified by indoor communication experiments with a code rate of 12.5 bps in the ULF band.

A mechanical antenna for long-wave communication by integrating piezoelectric material and magnets

“…This rotational motion is typically driven by motors. For example, Sun et al proposed a rotating shutter antenna that demonstrates indoor ultra-low frequency communication with a code rate of 12.5 bps [12]. Instead of using motors for magnet rotation, Mysore Nagaraja et al and Fereidoony et al placed permanent magnets in a pendulum array, employing external alternating current to stimulate their movement [13,14].…”