Research On EMF Propagation Characteristics In Marine Environment

The propagation characteristics of the electromagnetic field in layered media are complex.With the comprehensive influence of different medium layer to the electromagnetic field propagation,the theoretical study on the propagation characteristics of the electromagnetic fieldis more difficult,up to now,it is still in the stage of mathematical models about two-layered media.The mathematical model are so complex that is difficult to be directly used in convenient calculation upon the field strength.In seawater,the electromagnetic field mainly exists in the form of conduction current field.The complexity of the marine environment and the diversity of the communication scenarios,make the electromagnetic field propagation have many kinds of equivalent media models.In this paper,using the horizontal electric dipole as the antenna,the EMF propagation characteristics of the single conductive medium,two-layered media and three-layered media are studied respectively.The Electromagnetic simulation software,CST,is used to modeling and simulation.The number of CST modeling is nearly 90,and each of it had several times to optimize the grid to obtain a large number of reliable research data.And MATLAB is used to data research and analysis.By comparing CST simulation results and mathematical model results of a single conductive medium,the correctness of CST modeling and simulation method is proved.The EMF propagation characteristics of the air-sea two-layered media and seawater-seabed two-layered media are studied,and the EMF propagation path is analyzed.Under this research condition of two-layered media,the following conclusions are obtained: the relationship between EMF propagation distance and the two variables,electrode spacing and excitation current intensity are a power function;the relationship between EMF propagation distance and the two variables,electrode radius and antenna contact impedance,are real exponential function;the relationship between EMF propagation distance and the two variables,source-point depth and field-point depth,are complex exponential function.The EMF propagation characteristics of air-sea-seabed three-layered media is studied,and under the research condition,the relationship between EMF propagation distance and the sea-layer thickness is complex exponential function.The CST simulation capability is closely related with CPU performance,in this paper,the CST modeling and simulation are based on i7 6700 HQ,and the simulation ability is relatively high.This paper gives corresponding fitting functions of different experimental scene variable with the propagation characteristics of electromagnetic field,which provides a research method for the inconvenience of using CST,and provides the study basis of the experiment scene beyond CST simulation ability.The study results provided system parameter selection referenceof the corresponding outfield experiments.