ACES Publication Search
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| Title: | ACES Express Journal July 2018 Cover |
| File Type: | Express Journal Paper |
| Issue: | Volume: 33 Number: 7 Year: 2018 |
| Download Link: | Click here to download PDF File Size: 2161 KB |
| Title: | ACES Express Journal July 2018 Front/Back Matter |
| File Type: | Express Journal Paper |
| Issue: | Volume: 33 Number: 7 Year: 2018 |
| Download Link: | Click here to download PDF File Size: 496 KB |
| Title: | ACES Express Journal July 2018 Full |
| File Type: | Express Journal Paper |
| Issue: | Volume: 33 Number: 7 Year: 2018 |
| Download Link: | Click here to download PDF File Size: 16338 KB |
| Title: | Advanced Imaging for Down-Looking Contactless GPR Systems |
| Abstract: | This paper investigates the performance of an advanced imaging procedure for ground penetrating radar (GPR) operating in contactless configuration, i.e., when data are collected at variable distances from the air-soil interface. A data processing procedure is presented, based on an advanced implementation of a microwave tomographic approach. This improved version, recently proposed by the authors, is able of accounting for the near-field distribution generated by a directional transmitting antenna. The effectiveness of the procedure is shown by processing numerical data, which are obtained by suitably implementing a realistic system on a full-wave commercial simulator. Metallic canonical objects are considered to compare the reconstruction capabilities of the proposed algorithm with respect to more conventional procedures, as well as to assess the role of the antenna distance from the air-soil interface. |
| Author(s): | D. Comite, F. Murgia, I. Catapano, F. Soldovieri, A. Galli |
| File Type: | Express Journal Paper |
| Issue: | Volume: 33 Number: 7 Year: 2018 |
| Download Link: | Click here to download PDF File Size: 1920 KB |
| Title: | A High Resolution Algorithm for Null Broadening Beamforming Based on Subspace Projection and Virtual Antenna Array |
| Abstract: | In this paper, we proposed a high resolution algorithm for null broadening beamforming. The algorithm is based on the property of subspace orthogonal principle between signal and noise, and on virtual antenna array. By utilizing Capon spectrum estimator, we construct the correlation matrix to obtain projection transformation matrix, the width of null increases when original covariance matrix is processed by projection transformation matrix. In order to improve the depth of null and increase array resolution, virtual antenna technique is introduced. Also diagonal loading technique is used to form robust beam pattern. With the theoretical analysis and computer simulation, it’s demonstrated that the superiority of proposed algorithm corresponding other null broadening beamforming methods. |
| Author(s): | W. Li, H. Yang, Y. Mao |
| File Type: | Express Journal Paper |
| Issue: | Volume: 33 Number: 7 Year: 2018 |
| Download Link: | Click here to download PDF File Size: 1955 KB |
| Title: | On the Design and Simulation of Antennas on Ultra-thin Flexible Substrates |
| Abstract: | Flexible wireless systems are rapidly evolving in a wide spectrum of applications such as medical, entertainment and sport facilities. The aim of this paper is to investigate whether the ultra-thin substrates along with their permittivity are essential for the initial design stage of a flexible antenna, which is a key element of any wireless system, or it is merely a supporting structure. Three state-of-the-art simulation tools are used to evaluate the scattering parameter, S11 which are then compared against precise measurements conducted inside an anechoic chamber. These methods are the Finite Integration Technique (FIT) based Time Domain Solver (TDS) and the Finite-Element Method (FEM) based Frequency Domain Solver (FDS) of CST Microwave Technology and the (FEM) based HFSS of ANSYS. This paper attempts to provide an answer as to whether the substrate and other geometrically small features such as the feeding structure should be sufficiently discretized or else conventional default adaptive meshing should be enough. Three different flexible antennas with two fabrication techniques and feed lines have been used in the simulations and measurements. |
| Author(s): | A. Kashkool, S. Yahya, H. Al-Rizzo, A. Al-Wahhamy, A. A. Issac |
| File Type: | Express Journal Paper |
| Issue: | Volume: 33 Number: 7 Year: 2018 |
| Download Link: | Click here to download PDF File Size: 1629 KB |
| Title: | Modelling of Electromagnetic Scattering from Large and General Intakes on Complex Platforms |
| Abstract: | In the framework of the design of low observable aircraft, one of the most difficult problem is the numerical modelling of aeronautical air intakes with an – usually complex – arbitrary shape. Also the presence of radio absorbing material demands for accurate methods in evaluating the low level scattering for real life problems. This paper addresses the use of a full wave approach, based on the Multilevel Fast Multipole Approach (MLFMA), for a high fidelity modelling both of the whole (real life) aircraft, and of the intake scattering contribution, useful in the design and optimization stage of the intake itself. |
| Author(s): | A. Mori, S. Bertini, M. Bercigli, R. Scuderi, P. de Vita, S. Sensani |
| File Type: | Express Journal Paper |
| Issue: | Volume: 33 Number: 7 Year: 2018 |
| Download Link: | Click here to download PDF File Size: 2331 KB |
| Title: | A Finite Difference Frequency Domain Based Full Vectorial Transverse Modesolver for Anisotropic Waveguides with Arbitrary Permittivity and Permeability Tensors |
| Abstract: | In this work a Yee’s mesh based full vectorial transverse finite difference frequency (FDFD) modesolver has been derived from discretized Maxwell’s equations in Matrix form for anisotropic waveguides with arbitrary permittivity and permeability tensors. This work incorporates arbitrary permittivity and permeability simultaneously into matrix equations of Yee’s mesh based modesolver, which previous works have not done. For benchmarking the Python implementation of these matrix equations, cross section of Yittrium Iron Garnate (YIG) channel waveguide has been taken as first one of the three test structures. Numerical result from this work has been compared with that from previous work on YIG channel waveguide and is found to be in good agreement. Further, for benchmarking the effective index values of waveguides having both permittivity and permeability anisotropic simultaneously, a finite element based commercial software (COMSOL) has been used, the values of effective indexes from solver presented in this work and commercial software have been compared, and are also found to be in good agreement. |
| Author(s): | V. Singh |
| File Type: | Express Journal Paper |
| Issue: | Volume: 33 Number: 7 Year: 2018 |
| Download Link: | Click here to download PDF File Size: 1872 KB |
| Title: | Broadband Permittivity and Permeability Extraction of Ferrite Cores up to the GHz Range via Measurements and Simulations |
| Abstract: | In this contribution a method is presented which allows for the characterization of the magnetic (mu’-j mu’’) as well as the dielectric (epsilon’-j epsilon’’) properties of ferrites in a broad frequency band (kHz to GHz). In order to determine the material properties at certain frequencies, the simulation model parameters of a particular test setup are tuned via optimization such that the simulated response of a sample to an electromagnetic excitation matches to the measured one. A loop and parallel plate setup support a low frequency parameter extraction of the sample while a coplanar line is used for high frequencies. The extracted material properties are fitted by a broadband causal fit in order to obtain a material model for the whole frequency range. The presented method is verified for a setup with a coil and a ferrite core. The results show that dielectric properties of the ferrite core cannot be neglected for microwave frequencies. |
| Author(s): | C. Reinhold, P. Scholz, U. Jumar |
| File Type: | Express Journal Paper |
| Issue: | Volume: 33 Number: 7 Year: 2018 |
| Download Link: | Click here to download PDF File Size: 2466 KB |
| Title: | An HSS-Matrix-Based Fast Direct Solver with Randomized Algorithm |
| Abstract: | Discretization of the electric field integral equation (EFIE) generally leads to dense impedance matrix. The resulting matrix, however, can be compressed in sparsity based on hierarchical structure and low rank approximation. In this paper, we propose an HSS-matrix-based fast direct solver for surface integral equation (SIE) that has a compression complexity of O(rN2) to analysis the large-scale electromagnetic problems, where r is a modest integer. The proposed solver efficiently compresses the dense matrices using a randomized algorithm and requires modest memory. Efficiency and accuracy is validated by numerical simulations. In addition, being an algebraic method, the HSS-matrix-based fast solver employs Green’s kernels and hence is suitable for other integral equations in electromagnetism. |
| Author(s): | W. Yu, H. Yang, S. Li, Y. Xu |
| File Type: | Express Journal Paper |
| Issue: | Volume: 33 Number: 7 Year: 2018 |
| Download Link: | Click here to download PDF File Size: 1653 KB |
| Title: | A Compact CPW-Fed MIMO Antenna with Band-Notched Characteristic for UWB System |
| Abstract: | A compact coplanar waveguide (CPW)-fed multiple-input-multiple-output (MIMO) band-notched antenna with a small size of 20×36×0.8 mm3 for ultrawideband (UWB) system is proposed in this paper. The two rectangular monopole (RM) elements fed by CPW are printed on the FR4 substrate. To improve impedance bandwidth and the isolation, a T-shaped stub structure is positioned in the middle of two RM elements. The bandnotched characteristic is achieved by etching a U-shaped loop resonator slot on each RM element. The S11 reflection coefficients, S12 coupling isolation, radiation pattern, peak gain and radiation efficiency of the MIMO antenna are measured. The MIMO performance of the proposed MIMO antenna is analyzed and evaluated by the envelope correlation coefficient (ECC) and total active reflection coefficient (TARC). |
| Author(s): | L.-Y. Chen, J.-S. Hong, M. Amin |
| File Type: | Express Journal Paper |
| Issue: | Volume: 33 Number: 7 Year: 2018 |
| Download Link: | Click here to download PDF File Size: 1897 KB |