ULF Multi-Key Tunable Magnetoelectric Antenna Array with Enhanced Communication Data Rate

Low-frequency electromagnetic (EM) waves are essential in underwater, deep-earth, and other communication environments due to their minimal attenuation. The magnetoelectric (ME) antenna, a novel mechanical antenna, provides a promising solution for low-frequency EM wave communication, overcoming the limitations of conventional designs in terms of size and efficiency. To address the low transmission rate in low-frequency EM wave communication, this paper proposes a multi-key tunable antenna array based on an ME cantilever beam design. Each antenna array element consists of Metglas/0.7Pb(Mg_1/3Nb_2/3)O3–0.3PbTiO₃ (PMN-PT) ME composite. Simulations identified a structure that significantly lowers the resonant frequency, allowing the ME antenna array to operate within the ultra-low frequency (ULF, 300 Hz-3000 Hz) band. Furthermore, the resonant frequency can be tuned over a range of 500 Hz, enabling multi-frequency-shift keying (MFSK) communication. Using quaternary FSK (4FSK) modulation, a 40 baud color image transmission is successfully demonstrated in a 5 S m⁻¹ saline environment. Compared to binary FSK (2FSK) at the same baud rate, the transmission speed is increased by 100%. This approach achieves both low attenuation and high transmission rates, offering a promising new direction for ocean communications.