Electromagnetic Fields Generated Above a Shallow Sea by a Submerged Horizontal Electric Dipole

Abstract

Great attention has been paid to the propagation of electromagnetic (EM) waves across the sea surface due to its important applications. Most of the previous research, however, focus on the half-space model illustrating the deep sea environment. In this communication, by taking into account the presence of a seafloor, the EM fields generated above shallow sea by a submerged horizontal electric dipole have been investigated theoretically and experimentally with a three-layer model. A set of formulas for EM fields in air expressed by Sommerfeld integrals are derived with recursive propagation approach, and the fields are computed using a complementary numerical integration technique. The effects of frequency, sea depth, seafloor conductivity, and receiver height on the fields are discussed. An experiment was conducted on shallow sea, and the test results agree well with theoretical predication in the quasi-near range. A transmission distance over 3 km above the sea surface was realized with reasonable transmitting power, which shows the potential of our theoretical model for applications in shallow sea environment.