Spatial Radiation Field Distribution of Underwater VLF Two-Element Antenna Array

In this communication, we analyze the field distributions of underwater very-low-frequency (VLF) two-element array composed of two symmetrical antennas. This analysis is carried out with the improved parallel total-field scattered-field source (TSS) finite-difference time-domain (FDTD) method with sea–air boundary field value conversion and thin-wire algorithm. We specifically analyze the field distribution in the range close to the antenna array in seawater. Furthermore, we also study the field propagation law in air propagating across the air–sea interface.