نتایج جستجو برای: radar wave absorption

تعداد نتایج: 379710  

Journal: :Journal of the Optical Society of America. A, Optics, image science, and vision 2017
Dimitrios P Chrissoulidis Elodie Richalot

Electromagnetic scattering of a Gaussian beam by an off-axis dielectric sphere is treated by the sum-of-waves formulation, which is inherent in Lorenz-Mie theory. Each "wave" is a spherical eigenvector, defined in the natural frame of the scatterer, and the coefficient of that wave is the "wave amplitude." Decomposition of the beam into homogeneous plane waves lays the ground for a synthesis of...

2009
Othmane Benhmammouch Natacha Caouren Ali Khenchaf

This paper deals with works on radar links in a three-dimensional marine environment. Radar performances prediction represents an important phase in the radar system parameterisation. This prediction is strongly related to the electromagnetic waves propagation modelling in maritime environment. The modelling of propagation, in troposphere, requires a good consideration of meteorological paramet...

2004
Kodo Ito Toshio Nakagawa T. Nakagawa

Abstract An antenna of phased array radar (PAR) consists of a large number of individual radiating elements and steers its electromagnetic wave direction by shifting wave phases of these elements. Failed elements have to be detected, diagnosed, localized and replaced at scheduled times to hold a required performance of a radar system. However, the maintenance of an antenna should not be made so...

2006
A. Senior M. J. Kosch T. K. Yeoman M. T. Rietveld I. W. McCrea

Observations of HF radar backscatter from artificial field-aligned irregularities in an ionosphere perturbed by travelling disturbances due to atmospheric gravity waves are presented. Some features of the spatio-temporal structure of the artificial radar backscatter can be explained in terms of the distortion of the ionosphere resulting from the travelling disturbances. The distorted ionosphere...

2004
JAE HYENG LEE SATOSHI TAKEWAKA TAKAYUKI SAKAI

The present paper reports the observations of waves and beach morphology at two sites in Japan. One is the HORS Research Pier and the other is the Niigata coast where multiple shore protection structures have been installed. An X-band nautical radar system was employed for this study. Radar echo images provided instantaneous distributions of wave crests and waterlines along the shore. They were...

2012
Sixin Liu Junjun Wu Lili Zhang Hang Dong

Ground penetrating radar (GPR) is based on high-frequency electromagnetic wave propagation and its detecting targets are below the ground surface (Daniels, 2004; Jol, 2009). Velocity and attenuation are two important factors describing the electromagnetic wave in the media composed of rocks or soils. Velocity is inverse proportional to the root of the permittivity while other parameters are fix...

Journal: :Atmospheric Measurement Techniques 2016

Because of special structure, a dual reflector antenna has beam rotation capability in azimuth and elevation directions. In this structure, the antenna beam can be placed in any point in the space by mechanical movement of twist reflector which it is the most important ability of the antenna. Due to the antenna structure, if the polarization of incident wave is linear, it is expected that the p...

2012
M. N. V. Pavan Kumar

This paper deals with the use of the wave-radar for sea-state monitoring. The radar used here is popular as marine radar. SEA STATE monitoring by X-band Mare Radar system is becoming increasingly interesting, also due to its spatial resolution, which is much higher than the resolution of the relatively more common high-frequency (HF) coastal radars. In addition, compared to HF radar, Xband rada...

Journal: :Advanced composites and hybrid materials 2023

Multilayer radar absorbing materials with light weight, strong absorption, and wide absorption bandwidth are urgently demanded the increase of electromagnetic pollution. However, current design methods only simulation operation or optimization strategy not comprehensive. Here, a simulation-optimization approach including numerical calculation is proposed based on interaction between different s...

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