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Analytical Modeling of Rough Surface Scattering
Published in Kun-Shan Chen, Radar Scattering and Imaging of Rough Surfaces, 2020
So far, we have reviewed the integral equations governing the surface tangential fields. Numerical and analytical approaches are two typical solutions of the integral equations (EFIE & MFIE). The numerical evaluation of the forward-backward (FB) method is applied to scattering from a 1-D dielectric rough surface [7]. The Monte Carlo simulation based on the steepest descent fast multipole method (SDFMM) is used to compute the polarimetric scattering matrix for two-layered rough ground [8]. The numerical Maxwell model of three-dimensional (NMM3D) simulations was developed by Tsang et al. [9] to accelerate the Method of Moment (Mom) solutions. Though numerical methods, in general, may have the flexibility to deal with various types of rough surfaces, bulky computational resources are highly demanded. Here, we will seek the solutions of the integral equations with much emphasis on the analytical approach, as there are abundant publications in journal articles or books have devoted to numerically solving the integral equations.
C
Published in Philip A. Laplante, Comprehensive Dictionary of Electrical Engineering, 2018
column-access strobe column-access strobe memory organization. See two-dimensional the electric field integral equation (EFIE) and magnetic field integral equation (MFIE). It is normally used in electromagnetic scattering calculations from a conducting body to avoid nonphysical interior resonances that appear by using either EFIE or MFIE alone. combined source-channel coding a general term for approaches to source-channel coding, where the source and channel codes are combined into one overall code. In the literature, the term is also used, more loosely, for approaches where (any kind of) joint optimization of the source and channel coding is utilized. Also commonly referred to as joint source-channel coding. See also channel optimized VQ. combo trouble-shooter in combined electric and gas utilities, a practice which is growing in popularity is the use of combo troubleshooters.The combo troubleshooter is cross trained in both electric and gas service practices. The cross functionality permits more efficient deployment of resources. come-a-long a ratcheted winch or block-andtackle for pulling conductors into place. Comit' Consulatif International T' l' graphique e ee et T' l' phonique (CCITT) International Conee sultative Committee for Telegraphy and Telephony. This institution, based in Geneva, Switzerland, issues recommendations concerning all fields related to telecommunications. command (1) directives in natural language or symbolic notations entered by users to select computer programs or functions. (2) instructions from the central processor unit (CPU) to controllers and other devices for execution. (3) a CPU command, or a single instruction, ADD, LOAD, etc. Commision International d'Eclairage (CIE) International standards body for lighting and color
Integral Equations in Scattering Problems
Published in Edward F. Kuester, David C. Chang, Electromagnetic Boundary Problems, 2015
Edward F. Kuester, David C. Chang
This equation, together with any necessary edge conditions on JS at sharp edges,5 is sufficient to determine JS over all of S (except at resonant frequencies of the interior problem as discussed below). Equation (7.45) (which is obtained by imposing a boundary condition on the electric field) is known as an electric field integral equation (EFIE).
Low frequency scattering simulation of homogeneous objects in layered medium by Muller formed SIE
Published in Electromagnetics, 2023
As shown in Figure 1, a homogeneous dielectric object with the parameters is immersed in LM and is under the illumination of an electromagnetic field. According to the surface equivalence principle, an equivalent surface electric current and magnetic current on the surface will be generated. The scattered fields and by and can be represented by the electric field integral equation (EFIE) and magnetic field integral equation (MFIE) as (Chew 1995)
A hybrid method for electromagnetic scattering from target above composite rough surface of ground and near sea in adjacent region
Published in Electromagnetics, 2018
Gao Xiang Zou, Chuang Ming Tong, Hua Long Sun, Tong Wang, Peng Peng
IPO is on the basis of electric field integral equation (EFIE) and magnetic field integral equation (MFIE) which are deduced by Stratton-Chu equation. The main idea of IPO is iteration of induced electric/magnetic current. With several iterations, the induced electric/magnetic current will meet iterative error, and consequently the scattering field can be obtained. For solving the composite scattering problems, induced electric/magnet current must be iterated collectively because complex refractive index of dielectric surface in divisional circumstance may not meet the impedance boundary condition. The forms of principal value of integral equations are taken in the forms as follow:
A low-profile broadband circularly polarized metasurface antenna based on characteristic mode analysis
Published in Waves in Random and Complex Media, 2022
Jian Dong, Rigeng Wu, Xia Yuan, Jinjun Mo
To further study the working mechanism of the proposed CP MS antenna, CMA is used as an effective design method. The generalized characteristic mode equation is as follows: where [R] and [X] represent the real and imaginary parts of the impedance matrix of the electric field integral equation, respectively; and represent the characteristic value and characteristic current of a characteristic mode, respectively [17]. By using CMA to design the MS antenna, we use the modal significance to determine the approximate resonant frequency of the antenna. Modal significance refers to the inherent radiation characteristics of the antenna and is defined as follows: When the modal significance of a characteristic mode is equal to 1 at a certain frequency, it means that the antenna can reach the resonance state, and the radiation efficiency at this time reaches the maximum. The total current of the CMA can be expressed as a linear superposition of a series of mode currents: where the coefficient represents the degree to which each mode current can be excited, and is also called modal weighting coefficient (MWC). In addition, the characteristic angle (CA) represents the phase difference between the tangent component of the mode current and the mode electric field on the antenna surface, and can be calculated as follows: When the CA is equal to 180° at a certain frequency, the antenna is in resonance. In the following content, the characteristic modes of the proposed CP MS antenna are analysed in detail.