Millimeter Wave Attenuation by Log-normal Distribution of Seafoams using Finite Difference Algorithm of the Parabolic Equation Method

Abstract

This study predicts attenuation of electromagnetic waves due to its interaction with sea foams at millimeter wavelength. The interest is to develop a physical based model of sea foam takes account of its microstructural properties and foam layer thickness. Earlier research adopted empirical models to evaluate the presence of sea foam on the ocean surface to estimate microwave emissivity and brightness temperatures. The physical based model developed describes sea foams as air-bubbles coated with thin layer of seawater that is suitable for millimeter wave attenuation, as we model the foam layer as sequence of thin phase scattering screens. The air-bubbles are lognormally distributed with low geometric mean and large variance which is not negative but have zero cut-off. We adopt the finite difference algorithm of the parabolic equation method which is a range marching method to predict the millimeter wave propagation effects as electromagnetic wave interacts with various layers of sea foams. MATLAB simulation software was used to obtain results that show attenuation of millimeter waves at 10.7 𝐺𝐺𝐺𝐺𝐺𝐺 and 37 𝐺𝐺𝐺𝐺𝐺𝐺 for horizontal polarization (TE) and vertical polarization (TE) with incident angles (zenith 𝜃𝜃𝑖𝑖 = 30°, 45°) and (azimuth ∅ = 0°) as a function of depth of sea foam layers.

Keywords — Electromagnetic wave, Finite Difference Algorithm, Log-normal distribution, Parabolic

Equation Model, Sea foam, Wave attenuation.