ACES Publication Search
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| Title: | ACES August 2009 Full Journal |
| File Type: | Journal Paper |
| Issue: | Volume: 24 Number: 4 Year: 2009 |
| Download Link: | Click here to download PDF File Size: 6090 KB |
| Title: | ACES August 2009 Journal Front/Back Matter |
| File Type: | Journal Paper |
| Issue: | Volume: 24 Number: 4 Year: 2009 |
| Download Link: | Click here to download PDF File Size: 177 KB |
| Title: | A Closed-Form Sensitivity Analysis of Transmission Lines |
| Abstract: | A new approach for frequency-domain sensitivity analysis of transmission lines is presented. The propagation problem for the voltage sensitivity is considered and solved in terms of the closed-form Green’s function of the 1-D wave propagation problem. This leads to a closed-form solution for the voltage sensitivity. The accuracy of the proposed method is verified by comparison with the perturbation approach. |
| Author(s): | G. Antonini, L. De Camillis, F. Ruscitti |
| File Type: | Journal Paper |
| Issue: | Volume: 24 Number: 4 Year: 2009 |
| Download Link: | Click here to download PDF File Size: 1388 KB |
| Title: | Relationship Between the Path Loss Exponent and the Room Absorption for Line-of-Sight Communication |
| Abstract: | In indoor propagation, the log-distance path loss model represents the received power as declining with distance from the transmitter according to1/ r n , where r is the straight-line distance from the transmitter to the receiver. Previously, the value of the path loss exponent n has been derived from measured received signal strengths at a specific site. In this paper, the value of n is estimated from the geometry of the room and the electrical properties of the walls. Using the Sabine model, these determine the room absorption and hence the received power as a function of distance from the transmitter. Then, a least-square-error curve fit of the logdistance path loss model to the Sabine model determines the value of n . The electric field strength in a typical rectangular room is compared using ray tracing, the Sabine model, and the path loss model. Then the value of the path loss exponent is presented as a function of the power absorption coefficient of the walls, floor and ceiling of the room, for a typical ceiling height. Evaluating n from analytic information rather than from measurement enhances the usefulness of the path loss model in simulations of the coverage of antennas for the design of wireless local area network installations at specific sites. |
| Author(s): | C. W. Trueman, D. Davis, B. Segal |
| File Type: | Journal Paper |
| Issue: | Volume: 24 Number: 4 Year: 2009 |
| Download Link: | Click here to download PDF File Size: 181 KB |
| Title: | Optimum Cell Size for High Order Singular Basis Functions At Geometric Corners |
| Abstract: | Both low-order and high-order singular basis functions have been previously proposed for modeling edge singularities in the current and charge densities at geometric corners in electromagnetic integral equation formulations. This paper attempts to identify an optimum dimension for the cells adjacent to corners, as a function of the polynomial degree of the representation used away from the corner cells. The residual error obtained via the solution of an over-determined system of equations is used to judge the relative accuracy of various approaches. |
| Author(s): | M. M. Bibby, A. F. Peterson, C. M. Coldwell |
| File Type: | Journal Paper |
| Issue: | Volume: 24 Number: 4 Year: 2009 |
| Download Link: | Click here to download PDF File Size: 493 KB |
| Title: | Improved Version of the Second-Order Mur Absorbing Boundary Condition Based on a Nonstandard Finite Difference Model |
| Abstract: | It is often necessary to terminate the computational domain of an FDTD calculation with an absorbing boundary condition (ABC). The Perfectly Matched Layer (PML) is an excellent ABC, but it is complicated and costly. Typically at least 8 layers are needed to give satisfactory absorption. Thus in a 1003 domain less than 843 or 59% of the grid points are usable. The second-order Mur ABC requires just 2 layers, but its absorption is inadequate for many problems. In this paper we introduce an improved version of the secondorder Mur ABC based on a nonstandard finite difference (NSFD) model which has the same low computational cost but with much better absorption on a coarse grid. |
| Author(s): | J. B. Cole, D. Zhu |
| File Type: | Journal Paper |
| Issue: | Volume: 24 Number: 4 Year: 2009 |
| Download Link: | Click here to download PDF File Size: 315 KB |
| Title: | Comparative Study of Three Wave Propagation Software Programs for the Modeling of Coupled Maxwell and Boltzmann Equations at THz Frequency |
| Abstract: | The modeling of optoelectronic devices operating at THz frequency requires self consistently solving the Maxwell equations and the Boltzmann transport equation. In this article, it is the numerical method for solving Maxwell’s equations that is debated in the frame of its ability to be combined with transport equations. For this purpose, three software programs mainly devoted to the simulation of 3D electromagnetic equations in time-domain (one based on a 3D finite element method and two on 3D FDTD methods) are first presented and compared. The structure used for the modeling comparison is a coplanar waveguide structure. Results provided by the three solvers are compared according to two factors of merit. Then, the coupling of Maxwell and Boltzmann equations in the FDTD frame is briefly presented and the difficulties to use other methods are explained, showing that the variable-mesh FDTD method is most suitable for such a coupling. |
| Author(s): | B. Tissafi, F. Aniel, L. Pichon, B. Essakhi, C. Guiffaut, S. Lepaul |
| File Type: | Journal Paper |
| Issue: | Volume: 24 Number: 4 Year: 2009 |
| Download Link: | Click here to download PDF File Size: 376 KB |
| Title: | Plane Wave Scattering by Two Dielectric Coated Conducting Strips |
| Abstract: | A plane electromagnetic wave scattered by two dielectric coated conducting strips is addressed here. Two methods of solutions are introduced. The first is based on solving the Helmholtez wave equation in terms of elliptical coordinates. As a result a Fourier series of radial and angular Mathieu functions of unknown coefficients in each region is obtained. The unknown coefficients can be obtained by enforcing the boundary conditions. The application of the boundary condition requires the use of the addition theorem of Mathieu function. The second method is based on an asymptotic approximate technique introduced by Karp and Russek for solving scattering by wide slit. Numerical examples are calculated using both methods and they are compared with each other. Excellent agreement between both cases is found. |
| Author(s): | H. A. Ragheb, E. Hassan |
| File Type: | Journal Paper |
| Issue: | Volume: 24 Number: 4 Year: 2009 |
| Download Link: | Click here to download PDF File Size: 501 KB |
| Title: | Evaluating the Radar Cross Section of Maritime Radar Reflectors Using Computational Electromagnetics |
| Abstract: | This paper presents results from calculating the radar cross section (RCS) of two maritime radar reflectors using the method of moments. The Echomaster 152, although smaller in size, produces a higher maximum RCS than the Echomax 230 that includes three layers of corner reflectors. The Echomaster 152 also has deeper nulls in the RCS pattern, which means it is less detectable at those angles. |
| Author(s): | R. L. Haupt, S. E. Haupt, D. Aten |
| File Type: | Journal Paper |
| Issue: | Volume: 24 Number: 4 Year: 2009 |
| Download Link: | Click here to download PDF File Size: 647 KB |
| Title: | The Impact of Vertical Structures on Ship Radar Cross Section in the High Frequency Range |
| Abstract: | The monostatic and bistatic Radar Cross Section (RCS) of various complex ship targets are numerically simulated in the High Frequency range of 3- 20 MHz. The process by which these complex ship models are built and simulated using the FEKO code is described. Validation of the simulated RCS against fullscale measurements is described. Details are added to the ship model and the changes in the bistatic RCS are explored. Bistatic data from the simulations are used to assess the performance of a pair of surface-wave radar stations operated in a bistatic mode. The results of these findings will be of importance to future RCS simulation work using numerical modelling. |
| Author(s): | R. C. Solomon, H. Leong, C. W. Trueman, Y. M. M. Antar |
| File Type: | Journal Paper |
| Issue: | Volume: 24 Number: 4 Year: 2009 |
| Download Link: | Click here to download PDF File Size: 304 KB |
| Title: | Design of Wideband Planar Absorbers using Composite Materials |
| Abstract: | Design of planar microwave absorbers usually incorporates the use of either magnetic or electric lossy materials. In this study, chiral materials are included in the design process of these absorbers. The genetic algorithm is used to obtain suitable solutions satisfying the design requirements. Wideband absorbers are designed using different configurations and presented in this paper. It is shown that the inclusion of chiral materials in the design process leads to more efficient absorbers. |
| Author(s): | E. A. Hashish, S. M. Eid, S. F. Mahmoud |
| File Type: | Journal Paper |
| Issue: | Volume: 24 Number: 4 Year: 2009 |
| Download Link: | Click here to download PDF File Size: 366 KB |
| Title: | Simulations of a Shaped Dielectric Lens Antenna by FEKO |
| Abstract: | In the Intelligent Transportation System (ITS), millimeter waves are used and antennas are requested to have beam scanning ability. In the millimeter wave operation, a dielectric lens antenna is one of the prominent candidates. Authors designed a shaped dielectric lens antenna based on the Abbe’s sine condition. Wide angle beam scanning characteristics were ensured through the ray tracing calculations and radiation pattern measurement. Recently, owing to the enhancement of electromagnetic simulator abilities, simulations of a dielectric lens antenna become possible. By employing an electromagnetic simulation, it is expected that detailed electrical performances of both the feed horn and the dielectric lens will be made clear. In this paper, electromagnetic simulations of a shaped dielectric lens antenna by FEKO suit 5.3 are conducted. First, the corrugate horn used for the feed horn is electromagnetically simulated. Excellent simulated radiation patterns coinciding with the measured results are achieved. Next, the feed horn radiation patterns are combined with the dielectric lens simulations. And simulation results of beam scanning characteristics are obtained. When comparing the simulated scanned beam shapes with the measured results, very good agreements are obtained. So, accuracies of simulations are ensured. Moreover, unexpected sidelobe increases in the specific wide angle region that were pointed out previously are studied. Simulated and measured results can confirm the sidelobe increases. As an additional study, electrical field distributions in the dielectric lens are simulated. Then, multiple reflections between lens surfaces are visually made clear. The reason of sidelobe increases can be clearly understood. As a result, it is confirmed that the FEKO simulator can rigorously simulate electromagnetic characteristics of a shaped dielectric lens antenna. |
| Author(s): | Y. Tajima, Y. Yamada |
| File Type: | Journal Paper |
| Issue: | Volume: 24 Number: 4 Year: 2009 |
| Download Link: | Click here to download PDF File Size: 1594 KB |
| Title: | Cross Slot Antenna with U-Shaped Tuning Stub for Ultra Wideband Applications |
| Abstract: | A novel design of an Ultra Wideband (UWB) slot antenna is presented. This antenna operates as a transmitter and receiver antenna. Effects of the antenna dimensional parameters are studied through experimental and simulation results. Design procedures are developed and verified for different frequency bands. The experimental and simulation results exhibit good impedance bandwidth, radiation pattern and relatively stable gain over the entire band of frequency. Antenna gain and directivity at boresight and in their maximum states are close to each other and indicate high radiation efficiency. To use the antenna as a linearly polarized antenna, the radiation pattern in E-plane is better than that in H-plane. |
| Author(s): | D. S. Javan, O. H. Ghouchani |
| File Type: | Journal Paper |
| Issue: | Volume: 24 Number: 4 Year: 2009 |
| Download Link: | Click here to download PDF File Size: 393 KB |
| Title: | Analysis of Mutual Coupling in Interconnect Lines using Finite Difference Time Domain Method |
| Abstract: | In this paper, we present a simple technique for analyzing the mutual coupling effects in interconnects using the Finite Difference Time Domain (FDTD) method. The interconnect lines are divided into a set of uniform segments of parallel lines with short lengths. Next, the mutual capacitances and inductances of each of these segments are extracted by incorporating the FDTD solution into the telegrapher’s equations. Two examples of coplanar lines and microstrip lines on different dielectric substrates are studied. |
| Author(s): | N. Farahat, R. Mittra, J. Carrión |
| File Type: | Journal Paper |
| Issue: | Volume: 24 Number: 4 Year: 2009 |
| Download Link: | Click here to download PDF File Size: 360 KB |