ACES Publication Search
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| Title: | ACES Journal August 2012 |
| File Type: | Journal Paper |
| Issue: | Volume: 27 Number: 8 Year: 2012 |
| Download Link: | Click here to download PDF File Size: 9871 KB |
| Title: | ACES Journal August 2012 Front/Back Matter |
| File Type: | Journal Paper |
| Issue: | Volume: 27 Number: 8 Year: 2012 |
| Download Link: | Click here to download PDF File Size: 632 KB |
| Title: | A Comparison of the Element Free Galerkin Method and the Meshless Local Petrov-Galerkin Method for Solving Electromagnetic Problems |
| Abstract: | In this paper, the element free Galerkin (EFG) method and the local Petrov-Galerkin (MLPG) method are compared for solving the electromagnetic problems. The EFG method and MLPG method are introduced at first. Both of the EFG and the MLPG methods are formulated in detail with Poisson’s equation. Based on basic electromagnetic problems, the numerical results from the EFG method and MLPG method are given in this paper. The numerical results show that the EFG method and MLPG method both work well for the solution of electromagnetic problems. The EFG method, based on global weak form, needs background meshes for integration, and it needs more nodes to get an accurate result but it requires less cost in computational time. The MLPG method as a true meshless method doesn’t needs any meshes in the implementation and can obtain an accurate result using fewer nodes than EFG. However, because the MLPG Method needs more integration nodes and has asymmetric matrices, it needs more CPU time than the EFG method with the condition that the same number of nodes is used in the problem domain. |
| Author(s): | W. He, Z. Liu, R. K. Gordon, W. E. Hutchcraft, F. Yang, A. Chang |
| File Type: | Journal Paper |
| Issue: | Volume: 27 Number: 8 Year: 2012 |
| Download Link: | Click here to download PDF File Size: 635 KB |
| Title: | MoM Analysis of Apertures in Chiral Bodies of Revolution |
| Abstract: | A chiral body of revolution (BOR) which is partially covered by a thin conducting shield is analyzed using the Method of Moments (MOM). The axisymmetric system is excited by a plane wave. The internal fields and the far scattered fields are computed. The problem is solved using the surface equivalence principle. The scattered fields outside the structure are assumed to be produced by an equivalent magnetic surface current that exists on the unshielded part of BOR surface and an external equivalent electric surface current that exists over the entire BOR surface. These two currents are assumed to radiate in the unbounded external medium. Similarly, the internal fields are assumed to be produced by the negative of the above magnetic current and an internal electric surface current that exists over the entire BOR surface, but is an independent unknown only on the shielded part of the BOR surface. These two currents radiate in the unbounded internal medium. Enforcing the boundary conditions at the surface of the BOR results in a set of coupled integral equations for the three equivalent surface currents. These equations are solved numerically using the MOM. The computed results for the partially shielded spherical chiral body are in excellent agreement with other data. |
| Author(s): | K. Qutubuddin, H. Mustacoglu, J. R. Mautz, E. Arvas |
| File Type: | Journal Paper |
| Issue: | Volume: 27 Number: 8 Year: 2012 |
| Download Link: | Click here to download PDF File Size: 1861 KB |
| Title: | A Novel Enhancing Technique for Parallel FDTD Method using Processor Affinity and NUMA Policy |
| Abstract: | The traditional multiple CPUs mounted on one node in a high performance cluster is based on Symmetric Multi-Processing (SMP) architecture. The memory bandwidth is a major bottleneck in the high performance computing. Recently, Intel and AMD companies developed the (Non-uniform Memory Access (NUMA) architecture for the multi-CPU server that is an important extension of the SMP computer. In the NUMA architecture server, each CPU has its own memory and can also be access to the memory located the nearby of other CPUs through the onboard network. For a parallel code, we can allocate the data for each CPU inside its local memory to accelerate the memory access. In this paper, we investigate a way how to achieve the high performance of parallel FDTD code on a computer cluster that includes 21 nodes with 42 CPU and 168 cores. Numerical experiments have demonstrated that different job binding schemes can significantly affect the performance of parallel FDTD code. |
| Author(s): | L. Zhao, G. Chen, W. Yu |
| File Type: | Journal Paper |
| Issue: | Volume: 27 Number: 8 Year: 2012 |
| Download Link: | Click here to download PDF File Size: 1429 KB |
| Title: | A Comprehensive 2D FE-SIBC Model for Calculating the Eddy Current Losses in a Transformer Tank-Wall |
| Abstract: | The calculation of the eddy-current losses is one of the most important aspects that must be considered in the design of transformers and electrical machines. In this paper, a comprehensive 2D finite element (FE) model for calculating the eddy-current losses in a tank-wall of the transformer is presented. The FE model takes into account the Surface Impedance Boundary Condition (SIBC). A detailed 2D-SIBC formulation in terms of the magnetic vector potential is described. The SIBC is incorporated into the FE formulation by using the Galerkin method. An axi-symmetric electromagnetic model of the transformer is solved by applying the SIBC formulation for calculating the loss intensity distribution along the vertical tank-wall. To demonstrate the validity of the SIBC formulation, the results are compared against those computed with a model based on first-order triangular elements. The advantages of using the SIBC formulation in the modeling of power transformers are highlighted. |
| Author(s): | J. M. Díaz-Chacón, C. Hernandez, M. A. Arjona |
| File Type: | Journal Paper |
| Issue: | Volume: 27 Number: 8 Year: 2012 |
| Download Link: | Click here to download PDF File Size: 759 KB |
| Title: | A Novel Compact Monopole Antenna with Triple High Quality Rejected Bands for UWB Applications |
| Abstract: | A novel compact ultra-wideband (UWB) monopole antenna with triple high quality notch bands is presented. By attaching a T-shaped strip to the semicircular patch on the front side and adding a rectangular ring on the back side, a notch band for WiMAX is obtained. Furthermore, by symmetrically etching a pair of curved slots and a pair of L-shaped slots in the radiation patch, band rejected filtering properties in the lower WLAN band and upper WLAN band are also achieved. Experimental results show that the designed antenna, with compact size of 24×28mm2 has an impedance bandwidth of 2.75GHz-14.7GHz for VSWR<2, except three frequency stop bands of 3.3GHz-3.75GHz, 4.77GHz-5.4GHz,and 5.7GHz- 6.23GHz. Moreover, good omnidirectional radiation patterns in the H-plane are also obtained. |
| Author(s): | Z. L. Zhou, L. Li, J. S. Hong |
| File Type: | Journal Paper |
| Issue: | Volume: 27 Number: 8 Year: 2012 |
| Download Link: | Click here to download PDF File Size: 910 KB |
| Title: | Analysis of Electromagnetic Scattering Problems by Means of a VSIE-ODDM-MLFMA Method |
| Abstract: | The hybrid volume-surface integral equation (VSIE) method has the advantage of solving electromagnetic scattering problems involving complex structure mixed metal with dielectric. In this paper, a method combining VSIE with overlapped domain decomposition method (ODDM) is used to analyze electromagnetic scattering problems successfully. To further improve efficiency, the multilevel fast multipole algorithm (MLFMA) is adopted, then a novel VSIE-ODDM-MLFMA is proposed. Numerical results show that the proposed method has low memory requirement, fast convergence, and accurate simulation result. It indicates that the proposed method has the ability to analyze complicated electromagnetic problems. |
| Author(s): | J. Chen, S. Li, Y. Song |
| File Type: | Journal Paper |
| Issue: | Volume: 27 Number: 8 Year: 2012 |
| Download Link: | Click here to download PDF File Size: 435 KB |
| Title: | Parametric Design of Open Ended Waveguide Array Feeder with Reflector Antenna for Switchable Cosecant-Squared Pattern |
| Abstract: | This paper presents parametric analysis of two-dimensional (2D) open-ended waveguide array feeder and introduces a modified parabolic reflector antenna structure to obtain electronically switchable radiation patterns. The main motivation of the study is to achieve desired radiation characteristics for naval, air and coastal surveillance radars such as, pencil beam, suppressed side lobes and cosecant-squared pattern shapes. The Analytical Regularization Method (ARM) is used as a fast and accurate predesign tool to compute near and far field radiation characteristics of the feeder and reflector antennas. The numerical procedure is initially verified by the analytical methods and the calculated results are presented for the proposed novel designs. |
| Author(s): | O. M. Yucedag, A. S. Turk |
| File Type: | Journal Paper |
| Issue: | Volume: 27 Number: 8 Year: 2012 |
| Download Link: | Click here to download PDF File Size: 1297 KB |
| Title: | Investigations on a Novel without Balun Modified Archimedean Spiral Antenna with Circularly Polarized Radiation Patterns |
| Abstract: | The proposed novel modified twolayered Archimedean spiral (Mod Arspl) antenna achieves a simple feed without balun and maintains the antenna input impedance close to 50 ? over extremely wide (10:1) frequency band for antenna design. It shows excellent impedance matching, higher peak gain and acceptable axial ratio over the operating frequencies compared to the conventional Archimedean spiral geometry on two-layers with the same aperture area. The working of this antenna and important design parameters to achieve frequency independent response with respect to matching and CP radiation patterns are discussed. The best case with free-space Mod Arspl has impedance BW (S11 < - 10 dB) of 3.2-19.2 GHz (6:1 band), AR BW (AR < 3dB) of 3-20 GHz (6.6:1 band), stable broadside gain of 4-5.5 dBic and quasi-axial patterns in the usable 6:1 band. Radiation patterns show some beam squint towards higher frequency end attributed to spacing between the two layers of the spiral arms. The fabricated prototype antenna using microwave substrate shows CP operating BW over 5.21:1 frequency band (2.8 - 14.6 GHz) and peak gain varying between 4 - 8 dBic in this frequency band. Measured results show reasonable agreement with the simulated ones. |
| Author(s): | B. Shanmugam, S. K. Sharma |
| File Type: | Journal Paper |
| Issue: | Volume: 27 Number: 8 Year: 2012 |
| Download Link: | Click here to download PDF File Size: 2320 KB |
| Title: | Enhanced Bandwidth of Small Square Monopole Antenna by using Inverted U-shaped Slot and Conductor-Backed Plane |
| Abstract: | This paper, presents a novel multiresonance monopole antenna for ultra wideband applications. The proposed antenna consists of a square radiating patch with an inverted U-shaped slot and a ground plane with an inverted U-shaped conductor-backed plane, which leads to a wide usable fractional bandwidth of more than 135% (2.9-15.1 GHz). By cutting a modified inverted Ushaped slot with variable dimensions on the radiating patch and also by inserting an inverted U-shaped conductor-backed plane, additional resonances are excited and hence much wider impedance bandwidth can be produced, especially at the higher band. The designed antenna has a small size of 12×18 mm2 , or about 0.15? × 0.25? at 4.2 GHz (the first resonance frequency). Simulated and experimental results obtained for this antenna show that it exhibits good radiation behavior within the UWB frequency range. |
| Author(s): | N. Ojaroudi, M. Ojaroudi, Sh. Amiri |
| File Type: | Journal Paper |
| Issue: | Volume: 27 Number: 8 Year: 2012 |
| Download Link: | Click here to download PDF File Size: 761 KB |
| Title: | Compact CPW-Fed Planar Monopole Antenna with Triple-Band Operation for WLAN/WiMAX Applications |
| Abstract: | In this paper, we propose a compact coplanar waveguide (CPW) feed planar printed monopole antenna for WLAN/WiMAX applications. By employing two different types of structures-L-shaped slot and I-shaped notched slots, three distinct frequency bands with -10dB reflection coefficient, which correspond to 2.4GHz-2.6GHz, 3.4GHz-3.85GHz and the other at 4.9GHz-5.89GHz, can be achieved to covering 2.4/5.2/5.8 GHz WLAN and 2.5/3.4/5.5 WiMAX. Also, the antenna has a small size of 30mm×23mm, and can provide excellent property, including low profile, moderate gain, approximate omnidirectioal radiation pattern, which prove that the antenna is a good candidate for WLAN/WiMAX applications. |
| Author(s): | P. Wang, G. J. Wen, Y. Huang |
| File Type: | Journal Paper |
| Issue: | Volume: 27 Number: 8 Year: 2012 |
| Download Link: | Click here to download PDF File Size: 979 KB |