Abstract: Lowfrequency antennas have the advantage of low loss in extreme environment communication, but their traditional designs have the problem of limited effective transmission distance. The magnetic coupling receiving antenna utilizes the nearfield coupling mechanism, which can effectively enhance the reception efficiency of lowfrequency signals and has excellent lowfrequency reception characteristics. Focusing on the signal amplification mechanism of the magnetic coupling receiving antenna, the influence laws of its key parameters on the reception amplification performance were deeply analyzed, while considering impedance matching, aiming to optimize the design to achieve the best reception effect. The amplification gain coefficient was introduced as an evaluation index, and systematic modeling simulation and experimental tests were conducted on the designed magnetic coupling receiving antenna. Further underwater transmission experiments were carried out to explore its reception amplification performance in typical application environments. The results show that the optimized magnetic coupling receiving antenna can significantly improve the reception efficiency of lowfrequency signals under different environmental conditions. This technology shows broad application prospects in fields such as underground rescue and underwater communication, where there is an urgent need for lowfrequency signals.

Key words: lowfrequency antennas, magnetic coupling receiving antenna, impedance matching, underwater transmission