Acoustically Driven Piezoelectric Antenna for VLF Transmission and Reception

A portable piezoelectric antenna array for both very low-frequency (VLF) transmitting and receiving is proposed, based on piezoelectric lead zirconate titanate ceramics with the size of ∼10 cm, being 1/10 ⁵ of the wavelength. Piezoelectric antennas with plane electrodes show a large electromechanical coupling coefficient, leading to stronger mechanical vibration, which results in an enhanced radiation. For a pair of piezoelectric antennas, the measured radiation pattern is well consistent with the prediction and the maximum radiation capability of 80 m has been attained. Moreover, a linear increase in receiving signal amplitude with the number of elements in the transmitting antenna array has been proved. Binary amplitude shift keying modulation up to 800 bits/s has been successfully demonstrated on a pair of piezoelectric antennas. These results suggest that acoustically driven piezoelectric antennas have great potential for long-distance VLF communication by scaling up the piezoelectric antenna array.