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This paper presents several variants of the approach which can determine near-optimal radiation patterns under the constraint that the apertures (and therefore currents) for the elements do not overlap. Computational examples show that some of the methods can consistently provide performance which rivals that achievable with the optimal results for overlapping currents.
Linear embedding via Green's operators (LEGO) is a computational method in which the multiple scattering between adjacent objects - forming a large composite structure - is determined through the interaction of simple-shaped building domains, whose electromagnetic (EM) behavior is accounted for by means of scattering operators. This method has been successfully demonstrated for 2-D electromagnetic...
We have presented rapidly hybrid spectral-spatial techniques for the rapid calculation of 3D Green's functions of a linear periodic array residing in near a layered medium. The techniques are based on spectral field expansion over the transverse (to the array's axis) spectral parameter, extraction any singular field components, and efficient integration rules. The techniques are efficient for any...
The proposed approach combines the accuracy of the conventional rigorous methods with the flexibility of the high-frequency ray-tracing based techniques to handle complex real-world problems. We have obtained excellent results for a wide variety of test cases and we believe that the method is especially well suited for the analysis of large antennas, arrays and scattering problems for which rigorous...
In this work, the sequential code developed is effectively parallelized using the MPI. All objects are 2D perfect electric conductors (PEC) immersed in air. The illuminating waves are transverse magnetic (TM) plane waves where the electric field is parallel to the axes of the cylinders. The objective is to retrieve the number of scattering objects, their shapes and locations in few minutes versus...
In this paper we used a full vector three-dimensional (3D) multiplicative-regularized contrast source inversion (MR-CSI) method for inverting multi-frequency microwave scattered field data measured by the Institut Fresnel, Marseille, France. The 3D experimental setup consists of a transmitting and a receiving antenna. Twenty-one frequencies from 3 GHz to 8 GHz are used. The detailed setup of the apparatus...
In this paper, a marching-on in degree solution to the problem of time domain electric field integer equation is presented where the higher order basis functions are employed for the spatial expansion. The marching-on in degree method can obtain a solution that is late-time stable, which is marching-on in time method cannot. Numerical result is presented to show the accuracy of the MOD method with...
The aim of this paper is the study of some asymptotic properties and invariances of the electric field integral equation (EFIE) when applied to large and smooth structures. It is theoretical in nature, and thus no numerical results are included in this communication.
Scattering problems with multiple canonical scatterers, like cylinders and spheres, may be modeled by utilizing the orders-of-scattering approach. This method provides an exact solution; however, being iterative in nature, the accuracy of the solution depends on the number of iterations; in other words, the number of higher-order scattered fields taken into account. The orders-of-scattering solutions...
The method proposed by the authors to reduce the computational cost devoted to solve the full EM problem in such arrays is based in the macro basis function technique and the interpolation method. On the other hand, it is shown how the embedded element pattern convergence within a radius of influence allows us to account only for a few tens of significative elements when computing the aforementioned...
A self-loop basis functions is presented, a new set of solenoidal basis functions, which, together with the loop-star basis functions, define a rearrangement of the LL-discretization in method of moments of the EFIE that results in a stable impedance matrix at very low frequencies.
In this work we have extended the applicability of the GMM to a wide range of arbitrary geometries. The basis functions show excellent approximation qualities for the current, its curl and its divergence. In addition, the use of the surface Helmholtz decomposition results in a well conditioned system of equations over a wide range of frequencies. Future work is directed at fully utilizing these two...
The engineering design of antenna arrays requires the knowledge of the mutual coupling within and/or between antenna arrays, which is typically obtained by expensive and time-consuming measurements due to the limited capability of computational methods. Therefore, an efficient numerical method is highly desirable for such problems to speed up the design process, reduce the cost, and expand the optimization...
In this paper two distinct methods by which creeping wave radiation field can be obtained from its eigenfunction series has been shown. For the continuing investigations, the results for the creeping wave propagation constant results will be presented at the time of the conference for validation.
The new algorithm developed presents an advance in the analysis of the radiation pattern of antennas on board complex targets. The results shown verify the accuracy of this method and the efficiency in terms of CPU time.
Method of moments (MoM) is a powerful numerical tool for solving integral equation (IE) formulations of the boundary value problems in electromagnetics. The widely used low-order (LO) vector basis functions often require dense geometrical discretization to achieve sufficiently good accuracies. Great reduction of the number of unknowns for a given problem and desired accuracy is achievable through...
We introduce here a new MoM technique marrying the old idea of entire domain or large domain basis functions with a wide-spread computational geometry method known as the non-uniform rational B-spline (NURBS). The critical detail here is not in the expression of the object as a combination of NURBS curves and surfaces but in the specification of basis functions in the parameter space of the NURBS...
This paper is aimed at analyzing the applicability of ADSs (almost difference sets) to the design of thinned linear arrays, as well as the effectiveness of such an array synthesis technique in terms of beam-pattern features. Selected numerical results are provided to assess the performances of the proposed approach also in comparison with state-of-the-art thinning techniques with predictable PSL (peak...
In this paper, the level set shape reconstruction algorithm is implemented to retrieve multiple perfect conducting objects illuminated by Transverse Electric field (TE) where the magnetic field is parallel to the cylinders' axes. The results show good shape reconstruction for single and double objects.
The speeds of computers need to increase. A limitation to increasing this speed is the layout design of printed circuit boards (PCB's). One of the critical limiting factors of the PCB is the orientation of differential capacitors with respect to one another. This paper determines the optimal orientation of these capacitors in order to reduce the return loss (DS11) from crosstalk as the speeds of computers...
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