Complex Permittivity Research Of Seawater In Microwave Frequency Based On Double Ridge Waveguide Transmission Line Method

In the light of the characteristics such as the changeable environment,high frequency,and complex system structure of the millimeter wave mobile communication system in the marine environment,the high-efficiency simulation method of electromagnetic wave transmission and interference mechanism needs to study the electromagnetic modeling method applicable to the three-dimensional multi-scale complex marine scene of the millimeter wave communication system,with a focus on the development of rough surface modeling technology,the relationship between the marine environment material characteristics and temperature and frequency should be explored,and a reasonable parameter model of electromagnetic simulation of seawater,which has practical significance for air-ground(sea)communication,should be established.With the increasing frequency of maritime activities and the rapid development of the marine economy,marine communications have received more and more attention.In order to develop a new generation of high-rate millimeter-wave ocean wireless communication systems,obtaining the dielectric constant characteristics of seawater in the microwave frequency band in real time and accurately is playing an increasingly important role.In response to this situation,this paper proposes a method for testing the dielectric constant of seawater on the basis of transmission line method.The liquid to be tested is loaded into the Teflon medium container which is located in the double-ridge waveguide transmission line structure,and the rapid and accurate measurement of the complex permittivity of seawater under different temperatures and salinities in the 18-40 GHz band can be realized.The experimental results show that the method has high test accuracy and can measure the continuous change of complex dielectric constant with frequency in seawater.In the following paper,the measurement of other liquid dielectric constant is introduced,and its reliability is obtained by comparing with the double-ridged waveguide method.Then a measurement of the sea surface reflectance using the arched frame method is introduced,and the relationship between the sea water complex dielectric constant and its surface reflectance is studied,at a certain frequency,the sea surface reflectance increases with the incident angle of the incident wave.Finally,this paper introduces the sea path loss test in a certain sea area in Zhoushan,and compares the measured loss in the sea area of Zhoushan with the two-path road loss model in the sea area.Through this actual marine environment measurement,direct measurement and verification of typical sea channel characteristics,including path fading characteristics,multipath effects,and frequency window characteristics,etc.It can be seen from the analysis that the near-shore simulation and test results show a relatively weak attenuation window around 30 GHz,which also provides a certain frequency selection basis for the subsequent development of millimeter-wave communication systems.