Low-Power ULF Transmitter Design Using Static Permanent Magnet

This paper presents a low-power Ultra Low Frequency (ULF) transmitter design that uses a static, permanent magnet to bring the surrounding magnetic shield near saturation. A low-power control coil modulates this static magnetic field by toggling sections of the shield between saturated and unsaturated states. The transmitter, operating at 400 Hz and tested using a 3D magnetometer, demonstrated an increase of 22.3 dB along the pole at 800 Hz and a 17.7 dB increase at 400 Hz perpendicular to the pole, with a further 33 dB enhancement than the control coil's leakage at 800 Hz. These results highlight a novel method for efficient magnetic field modulation with significantly reduced power requirements compared to traditional approaches. This novel approach reduces power consumption and opens new possibilities for designing scalable, energy-efficient ULF communication systems, with potential applications in areas such as underwater communication, remote sensing, and long-range wireless networks.