ACES Publication Search
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| Title: | ACES August 2010 Full Journal |
| File Type: | Journal Paper |
| Issue: | Volume: 25 Number: 8 Year: 2010 |
| Download Link: | Click here to download PDF File Size: 6326 KB |
| Title: | ACES August 2010 Front/Back Matter |
| File Type: | Journal Paper |
| Issue: | Volume: 25 Number: 8 Year: 2010 |
| Download Link: | Click here to download PDF File Size: 474 KB |
| Title: | Fundamental Limitations on the Use of Open-Region Boundary Conditions and Matched Layers to Solve the Problem of Gratings in Metallic Screens |
| Abstract: | Interest in accurate modeling of the electromagnetic wave scattering from grating surfaces has been renewed due to recent advances in the manipulation and localization of the light in novel application of plasmonic resonance. This work briefly reviews the frequency-domain finite methods that have been used extensively to solve the grating problem. Emphasis will be placed on the finite methods that use local boundary operators or matched layers to truncate the computational boundary. It is shown that significant errors can be generated when using either of these two mesh truncation techniques even if the truncation boundaries are receded to avoid any evanescent waves emanating from the gratings. To quantify the error, the solutions obtained using the boundary condition or matched layers are compared to the solutions obtained using either mode matching or the surface integral equation method, both of which are devoid of truncation boundary related approximations and errors. Additionally, limitations on the use of the periodic boundary condition to truncate the mesh for periodic problems are also addressed. |
| Author(s): | B. Alavikia, O. M. Ramahi |
| File Type: | Journal Paper |
| Issue: | Volume: 25 Number: 8 Year: 2010 |
| Download Link: | Click here to download PDF File Size: 1492 KB |
| Title: | An Unconditionally Stable Subcell Model for Thin Wires in the ADI-FDTD Method |
| Abstract: | In this paper, a method for the implementation of thin wire with the alternating-direction implicit finite-difference time-domain (ADI-FDTD) method is discussed. The magnetic field around the wire is modified according to the “standard” subcell model, which results in the modification to the tridiagonal matrix system in the ADI-FDTD. The perfect-electric-conductor (PEC) condition is directly incorporated within the tridiagonal matrix equation. This method is efficient, stable, and suitable to ADI-FDTD scheme with large time step size. The validity of this method is confirmed through numerical examples. |
| Author(s): | J. Chen, J. Wang |
| File Type: | Journal Paper |
| Issue: | Volume: 25 Number: 8 Year: 2010 |
| Download Link: | Click here to download PDF File Size: 420 KB |
| Title: | A Frequency-Dependent Weakly Conditionally Stable Finite-Difference Time-Domain Method for Dispersive Materials |
| Abstract: | A frequency-dependent weakly conditionally stable finite-difference time-domain (WCS-FDTD) method for dispersive materials is presented. This method has higher computation efficiency than conventional FDTD method because the time step in this method is only determined by one space discretization. The accuracy of this method is demonstrated by computing the incident field at a planar air-water interface over a wide frequency band including the effects of the frequency-dependent permittivity of water. |
| Author(s): | J. Chen, J. Wang |
| File Type: | Journal Paper |
| Issue: | Volume: 25 Number: 8 Year: 2010 |
| Download Link: | Click here to download PDF File Size: 447 KB |
| Title: | Reconstruction of the Buried Homogenous Dielectric Cylinder by FDTD and Asynchronous Particle Swarm Optimization |
| Abstract: | In this paper, a time domain microwave imaging technique for reconstructing the electromagnetic properties of a buried homogeneous dielectric cylinder based on the finite difference time domain (FDTD) method and the asynchronous particle swarm optimization (APSO) are presented. The homogeneous dielectric cylinder with unknown electromagnetic properties is illuminated by transverse magnetic pulse and the scattered field is recorded outside. The idea is to minimize the errors between two E field data such that the location, shape and permittivity of the dielectric cylinder can be reconstructed through the APSO scheme. The first E field data are obtained in the forward problem by the FDTD code with fine grids to mimic the experiment measurement data, while the second E field data are obtained in the inverse problem by the FDTD code with coarse grids. The inverse problem is resolved by an optimization approach, and the global searching scheme APSO is then employed to search the parameter space. A set of representative numerical results is presented for demonstrating that the proposed approach is able to efficiently reconstruct the electromagnetic properties of homogeneous dielectric scatterer even when the initial guess is far away from the exact one. In addition, the effects of Gaussian noises on imaging reconstruction are also investigated. |
| Author(s): | C. Huang, C. Chen, C. Chiu, C. Li |
| File Type: | Journal Paper |
| Issue: | Volume: 25 Number: 8 Year: 2010 |
| Download Link: | Click here to download PDF File Size: 601 KB |
| Title: | Hybrid Electromagnetic and Non-Linear Modeling and Design of SIW Cavity-Backed Active Antennas |
| Abstract: | This paper presents the modeling and implementation of planar passive and active cavity-backed antennas in substrate integrated waveguide (SIW) technology. The cavity-backed topology helps suppressing the undesired surfacewave modes and may provide better phase noise performance in the antenna oscillator. The use of SIW technology allows for a compact and costeffective implementation of the structure. The design of the active antenna involves both electromagnetic full-wave modeling for the radiating structure and nonlinear analysis of the active circuitry through harmonic balance and transient simulations. Single substrate prototypes of both passive and active antennas operating in X band are presented and measured, showing good agreement with simulated results. |
| Author(s): | F. Giuppi, A. Georgiadis, M. Bozzi, S. Via, A. Collado, L. Perregrini |
| File Type: | Journal Paper |
| Issue: | Volume: 25 Number: 8 Year: 2010 |
| Download Link: | Click here to download PDF File Size: 2673 KB |
| Title: | A Simple Technique for Propagation Characteristics of Substrate Integrated Waveguide |
| Abstract: | A simple technique is presented for propagation characteristics of substrate integrated waveguide (SIW). A unit cell of the periodic structure is divided into consecutive rectangular waveguide sections with small difference in widths. Each section is modeled by a transfer matrix which is calculated by satisfying the boundary conditions on discontinuities. Propagation constant of the SIW is extracted by applying the Floquet theorem to the overall transfer matrix of a single unit cell. The results of this extremely simple method agree well with measured values and other numerical techniques reported in recent literatures. |
| Author(s): | E. Mehrshahi, M. Salehi |
| File Type: | Journal Paper |
| Issue: | Volume: 25 Number: 8 Year: 2010 |
| Download Link: | Click here to download PDF File Size: 437 KB |
| Title: | Positive-Negative-Positive Metamaterial Consisting of Ferrimagnetic Host and Wire Array |
| Abstract: | The positive-negative-positive metamaterial consisting of ferrimagnetic host and wire array is presented in this paper. Such metamaterial possesses three pass bands resulting from the interactions between the ferrimagnetic host and the wire array. The necessary parameter conditions are theoretically investigated and then the transmission and refraction properties are demonstrated by numerical method. The results show that the metamaterial exhibits three transmission peaks at frequencies of 7.1 GHz, 10.9 GHz, and after 15.5 GHz, respectively. The refraction directions at corresponding frequencies show that the metamaterial indeed exhibits positive-negative-positive refractive characteristics. Such metamaterial offers the potential applications, such as, multiband band pass filter, wavelength divider, and coupler. |
| Author(s): | Y. Huang, G. Wen, T. Li, K. Xie |
| File Type: | Journal Paper |
| Issue: | Volume: 25 Number: 8 Year: 2010 |
| Download Link: | Click here to download PDF File Size: 670 KB |
| Title: | Three-Dimension Finite Element Analysis of a Helical Motion Induction Motor |
| Abstract: | The paper presents a three-dimensional finite element analysis applicable to all forms of sheet rotor, cylindrical, linear induction motor, as well as, helical motion induction motor. The analysis accounts for longitudinal and transverse end effects, skin depth and finite sheet thickness; furthermore, there is practically no restriction on the shape of magnetic circuit that can be considered. It yields detailed space profile of the state variables. The winding arrangement may include multi-polar system circumferentially and axially. The excitation produced by such winding is a helically traveling wave. The formulation results in a set of linear equations which are solved by point relaxation method. The solution algorithm employs power mismatch in the machine to indicate accuracy. The theory is supported by experimental results. |
| Author(s): | J. H. Alwash, L. J. Qaseer |
| File Type: | Journal Paper |
| Issue: | Volume: 25 Number: 8 Year: 2010 |
| Download Link: | Click here to download PDF File Size: 352 KB |
| Title: | Micro-T Circuit Model for Double and Single Sided Induction Heating Systems |
| Abstract: | A method is given for obtaining a phase terminal equivalent circuit, which is useful for the analysis of traveling wave as well as longitudinal flux induction systems for heating thin metal strips. The excitation is transverse to the direction of strip motion and can be realized as a three phase system or a single phase system where the strip could be ferromagnetic or nonmagnetic. First, a general form of the field solution is obtained using transfer matrices. A variable transformation is then made which makes it possible to derive an equivalent circuit for each planar region in the system. By joining the equivalent circuits in cascade, an equivalent circuit for the complete system is obtained. The voltages and currents in the equivalent circuit relate directly to the field quantities within the actual system. |
| Author(s): | L. J. Qaseer |
| File Type: | Journal Paper |
| Issue: | Volume: 25 Number: 8 Year: 2010 |
| Download Link: | Click here to download PDF File Size: 279 KB |
| Title: | Corrections to ‘A Simplified Model for Normal Mode Helical Antennas’ |
| Abstract: | |
| Author(s): | C. Su, H. Ke, T. Hubing |
| File Type: | Journal Paper |
| Issue: | Volume: 25 Number: 8 Year: 2010 |
| Download Link: | Click here to download PDF File Size: 421 KB |