Prediction of the Magnetic State of Ferromagnetic Objects by Assimilating Data into a Physical Model

This paper presents a hybrid model to estimate the magnetic behaviour of a ferromagnetic structure. The mathematical-physical model has been developed using the Method of Moments combined with a hysteresis model. The mathematical model was derived by a linearisation of the hysteresis curve. The initial magnetic state of a ferromagnetic object is...

Fast Characterization of Mutually Coupled Array Antennas Using Isolated Antenna Far-Field Data

A new method is proposed to analyze antenna arrays including mutual coupling (MC), which is based on the concept of multiple scattering, and relates to the iterative Jacobi and Gauss–Seidel methods. The method employs sampled far-field data of an isolated element, which can be obtained by any full-wave simulator and consists of far fields for...

An Array of Tilted Dipoles Loaded with Artificial Dielectrics with an Asymmetric Pattern

We present the design of an array of tilted dipoles loaded with artificial dielectrics, to achieve asymmetric radiation patterns. First, a simplified array element consisting of skewed stacked dipoles in the presence of a backing reflector is studied, by means of a dedicated spectral periodic method of moments (MoM). The analysis of the stacked...

Analysis and Design of Arrays with Tilted Directive Dipole Elements

In this work, we present a study on the radiation and impedance properties of antenna arrays with tilted elements. We developed a spectral method of moments (MoM) for the analysis of doubly-periodic arrays with arbitrarily tilted dipole or stacked dipole elements, in free space or in the presence of a backing reflector. By using this analysis...

Radiation characteristics of skewed loaded dipole arrays

In this work we present a study to determine the parameters affecting the power radiated in specific directions by antenna arrays with tilted elements. We developed an efficient Method of Moments for the analysis of linear arrays with arbitrarily tilted dipole elements, in free space or in the presence of a backing reflector. By using this...

On the use of influence functions for subsidence evaluation

Fast models to estimate subsidence resulting from subsurface extraction processes usually employ a nucleus-of-strain solution based on a center of compression. The solution for such a strain nucleus is then employed as an influence function. This approach is based on the superposition principle that applies for linear elasticity of the...

An eigencurrent approach for the analysis of finite antenna arrays

An accurate description of typical finite-array behavior such as edge effects and array resonances is essential in the design of various types of antennas. The analysis approach proposed in this paper is essentially based on the concept of eigencurrents and is capable of describing finite-array behavior. In the approach numerical simulation is...

Interpolation Algorithm for Fast Evaluation of EM Coupling between Wires

Efficient and accurate evaluation of the EM field radiated by a current flowing along a wire is essential to solve the electromagnetic coupling between arbitrary oriented wires. In this paper, a numerically efficient algorithm for the evaluation of coupling is presented. The currents along the wires are expressed in terms of local basis...

Analysis of congestion periods of an m/m/∞-queue

A c-congestion period of an m/m/ ∞-queue is a period during which the number of customers in the system is continuously above level c. Interesting quantities related to a c-congestion period are, besides its duration Dc, the total area Ac above c, and the number of arrived customers Nc. In the literature Laplace transforms for these quantities...

Design of Wire Antennas by Using an Evolved Particle Swarm Optimization Algorithm

A Particle Swarm Optimization (PSO) algorithm has been used in conjunction with a full-wave numerical code based on the Method of Moments (MoM) to design and optimize wire antennas. The PSO is a robust stochastic evolutionary numerical technique that is very effective in optimizing multidimensional problems. The goal of the present work is to...

Problem-Matched Basis Functions for Microstrip Coupled Slot Arrays Based on Transmission Line Green's Functions (TLGF)

Problem matched basis functions are proposed for the method of moments analysis of printed slot coupled microstrips. The appropriate equivalent currents of the integral equation kernel are represented in terms of two sets of entire domain basis functions. These functions synthesize on one hand the resonant behavior of slots, microstrips or...

Problem-Matched Basis Functions for Microstrip Coupled Slot Antennas based on Transmission Line Greens Functions

A general algorithm for the analysis of microstrip coupled leaky wave slot antennas was discussed. The method was based on the construction of physically appealing entire domain Methods of Moments (MoM) basis function that allowed a consistent reduction of the number of unknowns and of total computation time. The basis function obtained were...

Phased arrays of rectangular apertures on conformal cylindrical surfaces: A multimode equivalent network approach

In this paper, we present an efficient integral equation formulation based on a multimode equivalent network (MEN) approach for the analysis of phased arrays on cylindrical surfaces using open-ended waveguide radiators. In addition to theory, experimental data are also presented showing very good agreement with simulated results. © 2004 IEEE.

Problem-Matched Basis Functions for Microstrip Coupled Slot Arrays based on Transmission Line Green+s Functions (TLGF)

A method is proposed for the analysis of arrays of linear printed antennas. After the formulation of pertinent set of integral equations, the appropriate equivalent currents of the Method of Moments are represented in terms of two sets of entire domain basis functions. These functions synthesize on one side the resonant behavior of the slot,...

Optimized basis functions for slot antennas excited by coplanar waveguides

A method is proposed for the analysis of slot antennas excited by coplanar waveguides. First, a standard integral equation for the continuity of the magnetic field is formulated. Then the appropriate equivalent magnetic currents of the method of moments are represented in terms of entire-domain basis functions which synthesize the resonant...

Effect of the foundation stiffness on the response of a seismically isolated tank under SSE conditions

This paper presents the results of a feasibility study of a seismic isolated 120.000 m³ LNG tank. A simple model was used to evaluate the seismic response of the isolated tank under Safe Shutdown Earthquake conditions. The frequency dependent dynamic stiffness of the foundation was modeled by means of Boundary Elements. Three possible...

Modeling radar backscatter from breaking waves on the surface

A model for describing radar sea clutter is proposed. It consists of two parts, an oceanographic and an electromagnetic one. The former contains swell, small capillary and gravity waves as well as breaking wave events. The latter combines ray tracing, Bragg scattering and the Method of Moments. It is shown that the combination of the two models...

Image-based aircraft pose estimation using moment invariants

The problem of estimating aircraft pose information from mono-ocular image data is considered using two different pose estimation algorithms. Both algorithms are based on the rotation invariant moment approach that was introduced by Dudani. The dependence of pose estimation accuracy on image resolution and aspect angle was investigated through...