Electromagnetic scattering and Doppler spectrum simulation of time-varying oil-covered nonlinear sea surface

2016 ◽  
Vol 10 (1) ◽  
pp. 016015 ◽  
Author(s):  
Pengju Yang ◽  
Lixin Guo ◽  
Chungang Jia
Keyword(s):  
Electromagnetic Scattering ◽  
Sea Surface ◽  
Doppler Spectrum ◽  
Time Varying ◽  
Spectrum Simulation

scholarly journals Doppler spectrum of microwave SAR signals from two-dimensional time-varying sea surface

2016 ◽  
Vol 30 (10) ◽  
pp. 1265-1276 ◽  
Author(s):  
Yunhua Wang ◽  
Yanmin Zhang ◽  
Huimin Li ◽  
Ge Chen
Keyword(s):  
Sea Surface ◽  
Doppler Spectrum ◽  
Time Varying ◽  
Two Dimensional

scholarly journals Scattering and Doppler Spectral Analysis for a Fast-Moving Target above Time-Varying Lossy Dielectric Sea Surface

2016 ◽  
Vol 2016 ◽  
pp. 1-11
Author(s):  
Ke Li ◽  
Lixin Guo ◽  
Juan Li
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Fast Moving ◽  
Large Scale ◽  
Sea Surface ◽  
Doppler Spectrum ◽  
Physical Optics ◽  
Moving Target ◽  
Time Varying ◽  
Lossy Dielectric

A numerical electromagnetic method based on the physical optics with physical optics method (PO-PO) is employed to calculate backscattered returns from a missile-like target above sea surface. Surfaces are time-varying Monte Carlo simulations initialized as realizations of a Pierson–Moskowitz spectrum. The monostatic normalized radar cross section of composite model by the hybrid PO-PO method is calculated and compared with those by the conventional method of moments, as well as the runtime and memory requirements. The results are found to be in good agreement. The runtime shows that the hybrid PO-PO method enables large-scale time-varying Monte Carlo simulations. The numerical simulations of the Doppler spectrum from the fast-moving target above time-varying lossy dielectric sea surface are obtained, and the Doppler spectra of backscattered signals from this model are discussed for different incident angles, speed of flying target, wind speeds, incident frequencies, and target altitudes in detail. Finally, the coupling effects on Doppler spectra are analyzed. All the results are obtained at the incidence of horizontal polarization wave in this study.

Near Field Electromagnetic Scattering Model Studying for Coarse Sea Surface

2013 ◽  
Vol 756-759 ◽  
pp. 4586-4590
Author(s):  
Jun Gu ◽  
Kun Cai ◽  
Zi Chang Liang
Keyword(s):  
Electromagnetic Scattering ◽  
Near Field ◽  
Horn Antenna ◽  
Measured Data ◽  
Sea Surface ◽  
Scattering Coefficient ◽  
Distributed Model ◽  
Echo Signal ◽  
Scattering Model ◽  
Rough Sea

The simulated PM-spectrum fractal sea surfaces and the 3-D near-field distributed model of horn antenna are built, the near-field formulas of KA method are deduced. The near-field scattering coefficient and the Doppler echo signal of rough sea surfaces are calculated, the agreement with measured data proved the correctness and validity of the near-field scattering model.

scholarly journals DOPPLER SPECTRUM MATHEMATICAL MODEL OF SIGNAL SCATTERING FROM SEA SURFACE AT LOW GRAZING ANGLES

2019 ◽  
Vol 22 (3) ◽  
pp. 63-73
Author(s):  
Mikhail A. Borodin ◽  
Vyacheslav N. Mikhaylov ◽  
Polina A. Filippova
Keyword(s):  
Mathematical Model ◽  
Electromagnetic Field ◽  
Surface Condition ◽  
Scattering Problem ◽  
Microwave Frequency ◽  
Ecological Monitoring ◽  
Sea Surface ◽  
Doppler Spectrum ◽  
Random Component ◽  
Grazing Angles

Introduction. Doppler spectra of signals which are scattered from sea surface and received by radar is used in oceanology and ecological monitoring applications. Existing models of Doppler spectra have the limitation of application because they are based on empirical data in changing conditions. Variability of the observation conditions critically influence on microwaves scattering by sea surface at low grazing angles which is typical for marine radiolocations. Objective. The goal of investigation proposed in this article is to develop the mathematical model of Doppler spectra at low grazing angles for microwave frequency range. Materials and methods. The two-dimensional problem of the scattering of an electromagnetic field on a cylindrical deterministic surface is considered. For generating of sea surface realizations is used linear model with spatial sea spectrum Elfohaily. The solution of the scattering problem is obtained for the case of vertical polarization of the incident electromagnetic field by the method of an integral equation with the control of the error of the solution. The mathematical modeling of the Doppler Spectrum of signal scattered by sea surface is produced by method of statistical trial. The case where the direction of the observation of the sea surface by radar is perpendicular to the direction of the wind is considered. The electromagnetic filed scattered in the direction of the radar receiver as a function of time is calculated for each generated sea surface realizations. Further, the set of variables of the implementation of scattered field is calculated for implementation of the Doppler spectrum. Results. The set of implementations of the Doppler spectrum provided its mathematical model with consist of deterministic and random component. The approximation of each aforesaid component is suggested and mathematical expressions for value component calculation are presented. The analyze of modeling result is produced. Conclusion. The developed mathematical model is offered to use for the design of algorithm sea surface condition estimation and pollutant detection using the signal which received by radar.

scholarly journals Time-varying metamaterials and metasurfaces for antennas and propagation applications

2021 ◽  
Vol 2015 (1) ◽  
pp. 012121
Author(s):  
D. Ramaccia ◽  
A. Toscano ◽  
F. Bilotti
Keyword(s):  
Electromagnetic Field ◽  
Electromagnetic Scattering ◽  
Surface Impedance ◽  
Frequency Conversion ◽  
External Control ◽  
Anomalous Scattering ◽  
Time Varying ◽  
Excitation Signal ◽  
Constitutive Parameters ◽  
Antenna Systems

Abstract In this contribution we present the most recent results from our group about the opportunities offered by time-varying metamaterials and metasurfaces for conceiving antenna systems and devices exhibiting artificial non-reciprocity, frequency conversion, energy accumulation and temporal electromagnetic scattering. Such artificial metastructures are characterized by constitutive parameters (permittivity, permeability and/or surface impedance) that are modulated in time through an external control or requires modulated excitation signal for enabling anomalous scattering behaviour. Here, we briefly describe the physical insights of the unusual interaction arising between the electromagnetic field and such metamaterials and metasurfaces, and then we present some antennas and propagation applications, showing the performances of non-reciprocal antenna systems, magnet-less isolators, Doppler cloaks, temporal devices and metasurface-based virtual absorbers.

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