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International Conference on Communications, Circuits and Systems (ICCCAS)

作者： Peng Yang ZhiYuan Yu The Institute of Physics and Electronics University of Electronic Science and Technology Chengdu China

ISBN: (纸本)0780386477

Generalized transmission line equations (GTLN) based on the solutions of the method of moments (MoM) have been proposed, and compared with conventional transmission line equations. Generalized transmission line equations have two additional terms, representing local radiation effects respectively. This paper uses generalized transmission line equations to model a two-gap microstrip filter; the exact circuit parameters on the assumed frequency restoring the S parameters successfully, demonstrates the GTLN not only can model the discontinuity of the structure, but also the gap of the structure.

关键词： Transmission lines Microstrip Distributed parameter circuits Voltage message-oriented middleware Differential equations Wire Frequency Scattering parameters Transmission line discontinuities

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Electromagnetic characteristics of spiro-helical antenna

Electromagnetic characteristics of spiro-helical antenna

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National Conference on Radio Science (NSRC)

作者： S.H. Zainud-Deen N.F.M. Soliman K.F.A. Hussein A.A.M. Shaalan Faculty of Electronic Engineering Menoufia University Egypt Faculty of Engineering Zagazig University Egypt Microwave Engineering Department Electronic Research Institute Egypt

The spiro-helical antenna (SHA) is analyzed using the method of moments (MoM). The analysis is validated by comparison with the power gain, input impedance and voltage standing wave ratio (VSWR) measurements. A comparison between the SHA and the conventional helical antenna is made. Higher gain and improved axial ratio are obtained. Also, the scattering characteristics of the SHA are investigated.

关键词： Helical antennas Antenna measurements Gain measurement Wire Impedance measurement Power measurement Spirals Transmitting antennas message-oriented middleware Numerical models

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Parasitic strip dipoles to suppress grating lobes in a waveguide transverse slot array

Parasitic strip dipoles to suppress grating lobes in a waveg...

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Antennas and Propagation Society International Symposium

作者： M.G.S. Hossain J. Hirokawa M. Ando Department of EEE Tokyo Institute of Technology Tokyo JAPAN

A parasitic strip dipole array is proposed to suppress the grating lobes in a waveguide broad wall transverse slot array. A parametric study is conducted to see the variation of coupled excitation coefficients on a waveguide broad wall transverse slot and on a parasitic strip dipole in half space by using the method of moments (MoM). Dipole parameters are optimized for the best possible case of grating lobe suppression while all slots are excited with the same magnitude of a constant magnetic current. It is found from analysis that the grating lobes of 0 dB can be suppressed down to -15 dB in the presence of the parasitic dipole array.

关键词： Arrayed waveguide gratings message-oriented middleware Magnetic analysis Dipole antennas Integral equations Reflection Parametric study Moment methods Loaded waveguides Surface waves

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Application of the multilevel adaptive cross-approximation on ground plane designs

Application of the multilevel adaptive cross-approximation o...

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IEEE International Symposium on Electromagnetic Compatibility (EMC)

作者： Kezhong Zhao M. Vouvakis Jin-Fa Lee ElectroScience Laboratory Department of Electrical Engineering Ohio State Uinversity Columbus OH USA

In this paper, the multilevel adaptive cross approximation (MLACA) technique is presented. This method reduces the numerical complexity of both memory requirement and matrix-vector multiplication of integral equation with asymptotically smooth kernels. The method does not require explicitly the knowledge of the integral kernel and therefore can be integrated into existing boundary integral equation (BIE) and/or MoM codes easily. This paper extends the ACA to oscillatory integral kernel and applies it to the ground plane designs. We have demonstrated through numerical examples that for moderate-sized problems (less than few hundred thousand unknowns) the multilevel ACA algorithm is still very effective and reliable for computer modeling of electromagnetic radiation and scattering problems.

关键词： Integral equations Kernel message-oriented middleware Electromagnetic scattering Moment methods Taylor series Algorithm design and analysis Electromagnetic modeling Electromagnetic radiation Geometry

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Mixing electromagnetic and electrical circuit simulations

Mixing electromagnetic and electrical circuit simulations

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Antennas and Propagation Society International Symposium

作者： W.C. Chew Y.H. Chu L.J. Jiang I.T. Chiang Y.C. Pan J.S. Zhao University of Illinois Urbana-Champaign Urbana-Champaign IL USA

ISBN: (纸本)0780383028

As clock rates in computers become faster, EM effects become more important in computer board and chip simulations. Hence, efficient computer simulations with the correct physics exploiting best CEM methods are imperative for the design of the next generation computers. The recently developed fast methods, MLFMA (multilevel fast multipole algorithm) and low-frequency MLFMA (LF-MLFMA), and low-frequency fast inhomogeneous plane wave algorithm (LF-FIPWA), can accelerate high-accuracy electromagnetic simulations by orders of magnitude. Such methods are integral equation methods such as MOM and low-frequency MOM (LF-MOM). LF-MLFMA/LF-MOM and LF-FIPWA/LF-MOM can be used to characterize blocks of circuits with S parameters when those parts of circuits are linear. Then we interface the nonlinear part of the circuits with the linear part with a fast convolution scheme with reduced complexity. In this manner, general circuits can be modeled by fully exploiting advances in fast electromagnetic solvers. Also, the characterization with S parameters over a broad range of frequencies can be done in parallel for different blocks of the circuit, and these parameters can be computed and stored for later simulations.

关键词： Circuit simulation Computational modeling MLFMA Computer simulation message-oriented middleware Scattering parameters Clocks Physics computing Acceleration Electromagnetic scattering

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MM/MoM CAD of broadband taper/branching OMTs utilizing stepped T-junctions

MM/MoM CAD of broadband taper/branching OMTs utilizing stepp...

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European Conference on Microwave

作者： F. Arndt V. Catina J. Brandt Microwave Department University of Bremen Bremen Germany Microwave Innovation Group Bremen Germany

A hybrid mode-matching (MM) / method-ofmoment (MOM) technique is applied for the accurate CAD and optimization of low-cost taperbranching ortho-mode transducers (OMTs) of improved performance. New aspects include the consideration of more general structures of the taper incorporating the branching section and the fact that the hybrid MMMoM technique achieves the fast direct optimization of such components within short time frames. The effcieucy and accuracy of the method is verified by comparison with available reference values. Its versatility is demonstrated at a WR-112 OMT example with stepped taper functions that also vary within the branching region achieving about 20% bandwidth.

关键词： message-oriented middleware Transducers Current density Electromagnetic waveguides Equations Bandwidth Design automation Magnetic fields Surface waves Admittance

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Design of a low side lobe aperture coupled microstrip antenna array

Design of a low side lobe aperture coupled microstrip antenn...

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IEEE International Conference on Multi Topic

作者： Z. Ahmed M.B. Ihsan N. Chaudhry J. Kiani National University of Science and Technology Pakistan NESCOM UK

A microstrip patch antenna that is coupled to a microstrip line by a slot in the intervening ground plane have been designed. The design was carried out using parametric study on MOM and FEM based EM analysis tools. A Ku-band 20 dB Dolph-Chebyshev array with 8 by 8 elements was designed and fabricated. Special attention is given for the design of feed network for the array. Discontinuities compensation techniques were applied to reduce the reactive behavior of the T junctions and bends. Both simulated and measured results are presented and compared. The results show good match between design and measurements. The aperture coupled antenna can be used for integrated antenna arrays at millimeter wave frequencies.

关键词： Microstrip antenna arrays Microstrip antennas Aperture coupled antennas Aperture antennas Antenna measurements Patch antennas Parametric study message-oriented middleware Feeds Antenna arrays

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Aperture antenna radiation 4

Aperture antenna radiation

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4th International Conference on Antenna Theory and Techniques

作者： Kozakoff, DJ Tripp, V DeVry Univ Alpharetta GA USA

ISBN: (纸本)0780378814

The technique that can be applied to the calculation of aperture antenna radiation patterns is the equivalence principle followed by physical optics. The equivalence principle is based on replacing the physical antenna aperture with a virtual antenna aperture consisting of an ensemble of Huygen's sources, each of which is a source of spherical wavelets. The total pattern is taken as a construction of these Huygen's secondary waves. A Fourier transform relation exists between the amplitude distribution of these sources, and the radiation pattern in angle space. For most aperture antenna problems, these classical techniques are adequate and give reasonably accurate results. However, more modern analysis techniques such as method of moments (MOM), finite element method (FEM), and the finite difference time domain (FDTD) method are also discussed. These are more robust and accurate, but the complexity and large amount of computer resources required must be traded off with the accuracy desired.

关键词： Antenna radiation patterns Aperture antennas Finite difference methods Finite element methods Fourier transforms message-oriented middleware Moment methods Physical optics Robustness Time domain analysis

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Evaluating the sustained performance of COTS-based messaging systems

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SOFTWARE TESTING VERIFICATION & RELIABILITY 2003年第4期13卷 229-240页

作者： Tran, P Gosper, J Gorton, I Pacific NW Natl Lab Richland WA 99352 USA CSIRO Math & Informat Sci N Ryde NSW 2113 Australia

Messaging systems, which include message brokers built on top of message-oriented middleware, have been used as middleware components in many enterprise application integration projects. There are many COTS-based messaging systems on the market, but there is little concrete understanding in the software industry on the performance of these different technologies. The authors have carried out a scenario-based evaluation of three leading messaging systems to provide insight into performance issues. The evaluation process includes a study of the sustained performance of the system under load. The result of this study is used to derive a generic metric for quantifying a messaging system's performance. The paper describes a synthetic transactional scenario, which is used for load tests and performance measurement. The results from executing this test scenario with three messaging systems are then presented and explained. Copyright (C) 2003 John Wiley Sons, Ltd.

关键词： message-oriented middleware message broker performance evaluation messaging system system validation test and validation

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Evaluating the sustained performance of COTS-based messaging systems

Evaluating the sustained performance of COTS-based messaging...

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1st International Workshop on Verification and Validation of Enterprise Information Systems (VVEIS 2003)

作者： Tran, P Gosper, J Gorton, I Pacific NW Natl Lab Richland WA 99352 USA CSIRO Math & Informat Sci N Ryde NSW 2113 Australia

关键词： message-oriented middleware message broker performance evaluation messaging system system validation test and validation

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