The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
In this paper the ability of SCT to simulate 1-D non-uniform finite patch arrays is demonstrated. It is shown that SCT has better convergence than the FEM based method which makes it a suitable tool for simulating large and complex structures. Moreover the modular nature of the SCT can be exploited toeconomize both memory and processing resources therefore making it an ideal design and optimization...
The analysis of periodic structures is of great interest for engineers and scientists in a variety of applications. EMC design, antenna design, photonics, and LO design are examples of such areas. In previous works, it has been shown by these authors and others that such analyses may be accurately accomplished in the frequency or time domain. While previous works have been successful for a variety...
The purpose of this work is to present the DISEP architecture together with a brief description of main features and capabilities of the software as well as some interesting case studies where we have successfully employed our code. It is important to note that the concepts and technological solutions herein presented are general enough to be applied, in a convenient manner, to speed up any parallelizable...
This work develops a previously unknown connection between the key results in Green's function extraction from field correlations , a field that is receiving enormous attention as the basis for a new "seismic interferometry" where "noise becomes signal", and an integral equation called Porter-Bojarski's equation which provides a complete formulation of the inverse source problem,...
Many physical materials that we wish to interrogate with electromagnetic signals are conductive. Thus, we need to understand the propagation dynamics of electromagnetic pulses through dispersive, conductive materials. Closed-form solutions are preferable to numerical solutions in that they provide an explicit expression for the dependence of the propagated field on the physical parameters. Here, we...
In this study, in order to arrive at an analytical representation for the effects of terrain roughness on the near-ground channel, new closed-form expressions for the effective reflection coefficient are presented. The basis of the derivation is founded on the perturbation approach applied to a volumetric integral equation as introduced by Sarabandi and Chiu for remote sensing applications involving...
This paper presents an efficient, 3-D alternating-direction-implicit finite-difference time-domain (ADI-FDTD) method for modeling wave propagation in Debye dispersive media. The efficient algorithm features a simpler, matrix-operator-free right hand side than the conventional ADI-FDTD method which results in substantial reduction of floating point operations (flops) counts and memory indexing. Formulation...
The paper summarizes the research results obtained on numerical modeling of the diffraction effects due to abrupt material or geometrical discontinuities of electromagnetic structures. High order polynomial vector bases are often used to numerically model EM problems, but polynomial approximations spoil the convergence properties of the used finite method whenever the physical quantities have singular...
Time-reversal radar imaging takes advantage of concepts based on time-reversed wave propagation to improve object resolution when these objects are located in a complex environment. There exists a multitude of propagation paths, making their imaging difficult. However, multipath can also be used to enhance the object location and shape. In the case of synthetic aperture radar (SAR) imaging, multipath...
A new structure that effectively behaves like ENZ material was proposed. This structure which is composed of parallel metallic wires allows super coupling and wave squeezing in waveguide junctions. The performance of the structure was numerically tested in a number of waveguide geometries with different junction shapes. The primary advantage of the structure proposed here is in its simple construction,...
Our focus is a unification of the generalized optical theorem facilitating discussion, within a unified general theory, of important effects of radiation and scattering in general nonhomogeneous propagating media, arbitrary excitation fields, and general representational domains (Green function representation, plane wave expansion, multipole expansion, and so on), among other aspects. The derived...
A novel technique to enlarge the absorption band of a high-impedance surface absorber has been proposed. The enlargement of the absorbtion band has been verified with numerical simulations.
Loop-tree bases are used to model the object in the current EPA scheme. Compared to the RWG based EPA, the new method can deal with the low frequency problem more accurately. Numerical results show the validity of the proposed scheme. More realistic and complicated testing examples will be considered in the future work.
A fast modeling of the wave propagation inside a rectangular room surrounded by walls of arbitrary thickness was presented. The solution was based on derivation and evaluation of the Green's function for the separable rectangular room, obtained by separation of variables method. The results for the test cases showed a good agreement when compared with the results obtained by the ray tracing technique.
In this paper, a very low loss CPW structure for application in submillimeter wave region is proposed and an optimized solution in terms of loss and dispersion is obtained. In this new structure, substrate is removed totally, which allows a pure TEM wave propagation. Furthermore, using the side walls in the structure, there are no higher order substrate mode excitations. The only remaining source...
Although diamagnetism in bismuth and antimony was discovered by S.J. Brugmans in 1778 and Michael Faraday coined the word ldquodiamagnetismrdquo in 1845 when he realized that all materials possessed some form of diamagnetic response to an applied magnetic field, classical power-energy relations in a diamagnetic continuum have not been determined. One reason for this is the Bohr-Leeuwen theorem, which...
We present elements of an algorithm suitable to accelerating solution of the three-dimensional radiative transfer equation (RTE) in its integral form, for applications in the context of electromagnetic wave propagation through dilute discrete media, e.g., clouds. Our approach is based on matrix compression and fast matrix-vector utilizing Fast Fourier Transforms (FFTs). We also outline a fast solution...
Parabolic wave equation (PWE) algorithms are widely used to model electromagnetic wave propagation in diverse environments. In most applications only the amplitude of received field is of interest, but the computed fields also contain phase information, which can subsequently be used for evaluating the effectiveness of angle-of-arrival (AOA) algorithms. In this paper, we use the chirp Z-transform,...
In this paper, we shall try to find out a useful marker with specific propagation feature for appropriately modeling outdoor/indoor interface environments, by analyzing diffraction problem for finite number of slits in an infinitely long PEC screen. In the present analysis, we utilize the Kobayashi potential (KP) method, which is a rigorous eigen-function expansion in terms of Weber- Schafheitlin...
A new and very general justification of the performances of the linear sampling method is presented. The constraint expressed by the far-field equation, together with energy conservation along the flow strips (or tubes in the 3D case) of the (time-averaged) Poynting vector associated to the field whose far-field pattern is the difference between the two sides of the far-field equation, force any approximate...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.