ACES Publication Search
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| Title: | ACES Journal September 2015 Cover |
| File Type: | Journal Paper |
| Issue: | Volume: 30 Number: 9 Year: 2015 |
| Download Link: | Click here to download PDF File Size: 1713 KB |
| Title: | ACES Journal September 2015 Front/Back Matter |
| File Type: | Journal Paper |
| Issue: | Volume: 30 Number: 9 Year: 2015 |
| Download Link: | Click here to download PDF File Size: 103 KB |
| Title: | ACES Journal September 2015 Full |
| File Type: | Journal Paper |
| Issue: | Volume: 30 Number: 9 Year: 2015 |
| Download Link: | Click here to download PDF File Size: 13740 KB |
| Title: | SAR Induced by Low and High Directivity Antenna Apertures at Distances Greater than 25 mm from the Body |
| Abstract: | A comprehensive SAR study of low and high directivity antennas operated at distances greater than 25 mm but less than 200 mm from a large homogeneous elliptical phantom is presented. The study considers antennas, such as dipoles, monopoles, planar inverted-F antennas (PIFAs), IFAs, patches, patch arrays, and dipole arrays. SAR estimation methods for low directivity antennas for both near and far field conditions are proposed and elucidated. For directive antennas and arrays radiating directly towards the phantom interesting phenomena are observed that require more detailed investigation |
| Author(s): | A. B. Mazady, G. Schmid, R. Uberbacher, M. Ali |
| File Type: | Journal Paper |
| Issue: | Volume: 30 Number: 9 Year: 2015 |
| Download Link: | Click here to download PDF File Size: 958 KB |
| Title: | Design of Shaped-Beam Parabolic Reflector Antenna for Peninsular Malaysia Beam Coverage and its Overlapping Feed Issues |
| Abstract: | Design and performance of a shaped beam 12.2 GHz array-fed reflector antenna for broadcasting satellite is presented in this paper. Initial design, employing a cluster of feed horns illuminating a parabolic reflector is initially proposed for multi beam antenna (MBA) system to produce a contoured beam for Peninsular Malaysia. The precise feed positions are determined through a newly developed ray tracing program. Due to the small size of the coverage area, an issue with regards to physical constructability of the feed horns is raised. The MBA is modified by utilizing 18- element microstrip array as the feed, where each element positions are calculated by using the same caustic model. In this case, the preceding issue is solved, and high gain shaped beam coverage with uniform aperture is generated. This paper shows the results of the contoured beam antenna that have been achieved for beam scanned over a coverage size of approximately 0.9° long and 0.5° wide. Small variation of radiation level, which is less than 3dB within the edge of coverage (EOC), is also demonstrated in the performance analysis. |
| Author(s): | N. H. Abd Rahman, M. T. Islam, Y. Yamada, N. Michishita |
| File Type: | Journal Paper |
| Issue: | Volume: 30 Number: 9 Year: 2015 |
| Download Link: | Click here to download PDF File Size: 1864 KB |
| Title: | Enhancement of Scan Angle Using a Rotman Lens Feeding Network for a Conformal Array Antenna Configuration |
| Abstract: | An antenna with a wide scan angle in a wide frequency band is obtained by feeding a conformal arc array with a modified formulation of Rotman lens design. In this paper, two kinds of Rotman lenses are designed to feed a linear array and a conformal array and their scan angles are compared in a specified frequency band. The phase distributions of the linear array elements are linear in all scan angles, but these phase distributions are nonlinear in the conformal array. Therefore in order to design a Rotman lens for conformal arrays, the conventional Rotman lens design formulations must be modified. For this purpose, first the phase distributions of conformal array elements were obtained using the particle swarm optimization (PSO) process. Then by modifying the conventional Rotman Lens design formulations used for linear arrays, appropriate formulations for conformal arrays are obtained. In the end, by selecting two specified linear and conformal arrays with equal number of elements, their maximum scan angles in a specified frequency band are studied. It is shown that in the same frequency band the maximum scan angle increases about 20% in the Rotman Lens fed conformal array antenna. |
| Author(s): | A. Mahmoodi, A. Pirhadi |
| File Type: | Journal Paper |
| Issue: | Volume: 30 Number: 9 Year: 2015 |
| Download Link: | Click here to download PDF File Size: 1556 KB |
| Title: | Reflectarray Nano-Dielectric Resonator Antenna Using Different Metals |
| Abstract: | Nano-antennas have been introduced with wide bandwidth for faster data communications. The material properties of good conducting metals introduce plasmonic behavior at THz frequencies. The material property of good conducting metals using the Durde Lorentz model have been investigated. The radiation characteristics of nano-dielectric resonator antenna NDRA reflectarray at 633 nm have been investigated. A parametric study for the NDRA unit-cell dimensions and material has been introduced. Different types of metals are used as a supporting plane of the NDRA unit-cell. A NDRA with silver, copper, and aluminum supporting plane have been designed and analyzed for reflectarray antennas. A nano-reflectarray unit-cells with supporting plane having different metals have been introduced. Comparisons between the radiation characteristics of reflectarrays with different supporting plane metals have been illustrated. A compromise between the size, maximum gain, and operating bandwidth of the nanoreflectarray is investigated for terahertz applications. The finite integral technique is used to carry a full wave analysis to design a NDRA reflectarray. |
| Author(s): | H. A. Malhat, N. A. Eltresy, S. H. Zainud-Deen, K. H. Awadalla |
| File Type: | Journal Paper |
| Issue: | Volume: 30 Number: 9 Year: 2015 |
| Download Link: | Click here to download PDF File Size: 783 KB |
| Title: | Compact Triple-Band S-Shaped Monopole Diversity Antenna for MIMO Applications |
| Abstract: | In this paper, a novel WLAN frequency range monopole antenna is designed and manufactured for MIMO applications. The proposed antenna consists of two L-shaped slots in the S-shaped radiating patch. In this structure, the S-shaped monopole antenna can create dual resonances within the WLAN frequency range. The placement of two L-shaped slots within the S-shaped monopole antenna creates an extra resonance and the desired resonant frequencies are obtained by adjusting the dimension of the S-shaped monopole and the Lshaped slots. The operating frequencies of the proposed antenna are 2.4/5.2/5.8 GHz, which covers WLAN systems. Also, the two elements array configuration of this S-shaped monopole antenna which can be used in MIMO with a very high isolation over three operational bands is studied. The prototypes of the proposed antenna have been constructed and studied experimentally. Good diversity performance, return loss and radiation pattern characteristics are obtained in the frequency band of interest. Simulated and measured results are presented to validate the usefulness of this small proposed antenna structure for MIMO applications. |
| Author(s): | Jalil Mazloum, S. A. Ghorashi, M. Ojaroudi, N. Ojaroudi |
| File Type: | Journal Paper |
| Issue: | Volume: 30 Number: 9 Year: 2015 |
| Download Link: | Click here to download PDF File Size: 1221 KB |
| Title: | Study on Band Gaps of the Photonic Crystal in THz Frequency Range Based on the Periodic WCS-PSTD Method |
| Abstract: | In this paper, a periodic weakly conditionally stable -pseudospectral time domain (WCS-PSTD) method is presented to simulate photonic crystal in Terahertz frequency range. The time step size in this method is only determined by the mesh length -z and the spatial discretization along the z direction only needs two cells per minimum wavelength. The 3D formulas of the method are presented and the time stability condition of the method is demonstrated. Numerical results show that this method is more efficient than the periodic finite difference time domain (FDTD? method in terms of computer memory and computation time. |
| Author(s): | J. Chen, A. Zhang, J. Li |
| File Type: | Journal Paper |
| Issue: | Volume: 30 Number: 9 Year: 2015 |
| Download Link: | Click here to download PDF File Size: 579 KB |
| Title: | Reconfigurable Circular Polarization Antenna with Utilizing Active Devices for Communication Systems |
| Abstract: | ? In this paper, the reconfigurable antenna with circular polarization diversity is proposed for wireless local area network (WLAN) communication systems. The proposed antenna consisting of two PIN diodes are appropriately positioned to achieve polarization diversity. By switching the PIN diodes ON/OFF mode, the proposed antenna enables to operate either RHCP mode or LHCP mode. A good impedance match (S11 ? -10 dB) of 935 MHz (1.995~2.930 GHz) at RHCP mode, an impedance bandwidth (S11 ? -10) of 965 MHz (1.935~2.960 GHz) at LHCP mode. The experimental result shows that the proposed antenna has a circular polarization bandwidth (AR ? 3 dB) of about 415 MHz at the center frequency of 2.4 GHz for both RHCP and LHCP mode. |
| Author(s): | V. Zarei, H. Boudaghi, M. Nouri, S. A. Aghdam |
| File Type: | Journal Paper |
| Issue: | Volume: 30 Number: 9 Year: 2015 |
| Download Link: | Click here to download PDF File Size: 1066 KB |
| Title: | Terahertz Dielectric Sensor Based on Novel Hexagon Meta-Atom Cluster |
| Abstract: | In this paper, we report meta-atom sensor based on planar hexagon split ring resonators. The subwavelength structure is designed to operate in terahertz frequency band. A modified version of split ring resonator geometry is simulated for sensing dielectric changes by placing thin dielectric layers as sample materials on the full frontal surface of sensor. The effective parameters are retrieved using Nicolson-Ross and Weir method. The meta-atom sensor shows significant changes in resonant frequency as a function of transmission (magnitude of S21 parameter) response, which was observed when the sensor is loaded with the dry layer of dielectric materials of different dielectric constants. This paper contributes new shape of metaatom structure used as a terahertz dielectric sensor. The proposed sensor can be used in multitudinous terahertz near field sensing applications. |
| Author(s): | N. Naeem, A. Ismail, A. R. H. Alhawari, M. A. Mahdi |
| File Type: | Journal Paper |
| Issue: | Volume: 30 Number: 9 Year: 2015 |
| Download Link: | Click here to download PDF File Size: 790 KB |
| Title: | Using MATLAB to Model Inhomogeneous Media in Commercial Computational Electromagnetics Software |
| Abstract: | This paper presents a new method to model inhomogeneous media in commercial electromagnetics software, especially FEKO. In this method, the inhomogeneous medium is fragmented to some homogeneous pieces. If the size of these pieces is chosen correctly, then the electromagnetic behaviors of them and inhomogeneous medium are the same. Since creating these homogeneous pieces in FEKO manually is very difficult and time consuming, MATLAB is employed to create these pieces in FEKO. |
| Author(s): | A. Farahbakhsh, D. Zarifi, A. Abdolali |
| File Type: | Journal Paper |
| Issue: | Volume: 30 Number: 9 Year: 2015 |
| Download Link: | Click here to download PDF File Size: 511 KB |
| Title: | Influence of the Simulation Parameters on the Normalized Impedance Derived by the Random Coupling Model Simulation |
| Abstract: | The random coupling model (RCM, introduced by the “chaos group” in the University of Maryland, is found of great use in making statistical predictions of the induced voltages and currents on objects or components within complicated (wavechaotic) cavities when excited by external high power microwave (HPM) radiation. A key point to applying the RCM to a real system is to generate the normalized cavity impedance, which can be described by the random matrix theory (RMT), from the cavity loss parameter by using random matrix Monte Carlo simulation. The influences of the simulation parameters on the statistics of the generated normalized impedance are presented and discussed in this paper. It’s found that the statistics of the normalized impedance only depends on the loss parameter, ?, which agrees with the theory. When ? increases, the variances of the eigenvalues, the diagonal elements and the off-diagonal elements of the normalized impedance are exponentially damped with different damping factor, which are experimentally verified in the paper. |
| Author(s): | X. Li, C. Meng, Y. Liu, E. Schamiloglu |
| File Type: | Journal Paper |
| Issue: | Volume: 30 Number: 9 Year: 2015 |
| Download Link: | Click here to download PDF File Size: 1375 KB |
| Title: | Optimization of Impedance Bandwidth of a Stacked Microstrip Patch Antenna with the Shape of Parasitic Patch's Slots |
| Abstract: | In this paper, a novel configuration of wideband stacked microstrip antenna for X/Ku band is presented and analyzed. By cutting five narrow rectangular and one trapezoidal slot on parasitic patch with different dimensions, the impedance bandwidth and resonance frequency of the proposed antenna is adjusted. Also, the effect of incorporated parallel slots on driven patch is examined based on equivalent circuit of E-shaped microstrip antenna. Antenna characteristics are simulated by CST simulator and far-field radiation patterns of simulated and measured results of an array of the proposed antenna are compared. |
| Author(s): | Z. Manzoor, G. Moradi |
| File Type: | Journal Paper |
| Issue: | Volume: 30 Number: 9 Year: 2015 |
| Download Link: | Click here to download PDF File Size: 852 KB |
| Title: | Design of Balanced SIW Filter with Transmission Zeroes and Linear Phase |
| Abstract: | This paper provides a design method for balanced bandpass filters (BPFs) with high performance based on substrate integrated waveguide (SIW) structure. A novel balanced SIW filter with the characteristics of transmission zeroes, linear phase and wideband common-mode suppression is proposed. By analyzing the equivalent circuits of the proposed SIW filter under differential-mode (DM) and common-mode (CM) excitations, the DM transmission with CM suppression characteristic of the filter is demonstrated. The source-load coupled microstrip lines are introduced to realize the negative coupling and the design method for filters with source-load coupling is given. Good agreement is demonstrated between the simulated and the measured ones |
| Author(s): | Q. Xiao, C. X. Zhou |
| File Type: | Journal Paper |
| Issue: | Volume: 30 Number: 9 Year: 2015 |
| Download Link: | Click here to download PDF File Size: 598 KB |
| Title: | Compact Dual-Wideband BPF Based on Quarter-Wavelength Open Stub Loaded Half-Wavelength Coupled-Line |
| Abstract: | In this paper, a novel dual-wideband bandpass filter (BPF) is presented by using quarterwavelength open stub loaded half-wavelength coupledline. Equivalent voltage-current analysis method is applied to analyze this structure, which shows it has two tunable transmission zeros and dual-wideband frequency response. As an example, a dual-wideband BPF covering 1.228/1.57/6.8 GHz for GPS (Link 1 and Link 2) and RFID applications is designed, fabricated and measured. The fabricated filter has a compact size of 0.043g × 0.213g. The measured results show that the fabricated filter has the merits of low insertion loss, good return loss and high band-to-band isolation. The proposed dual-band BPF also has a very simple physical topology and quick design procedure. |
| Author(s): | J. Xu |
| File Type: | Journal Paper |
| Issue: | Volume: 30 Number: 9 Year: 2015 |
| Download Link: | Click here to download PDF File Size: 835 KB |
| Title: | Study of Various C-Shaped Armatures in Electromagnetic Launcher |
| Abstract: | The current density distribution on the cross section of the rails is affected by the geometry and dimensions of the rails and armature. This paper analyzed a rectangular railgun that is formed by two parallel rails and an armature with various geometries. Rail thickness (wr), width (hr), and separation (sr) between two rails are equal to 2 cm, 4 cm and 4 cm, respectively. C-shaped armatures have three corners that are named front, back and arm side of armature which rounded step by step. All case studies simulated with the Finite Element Method Three Dimensions (FEM3D). For all steps, the inductance gradient, normal force, current density (J) distribution and maximum values of J are computed. The force between rails and armature named normal force. This force and pressure can be changed the rails and armature form. Friction force is increasing with increasing normal force. Maximum current densities occur at the armature corners and contact section between the rails and armature. These phenomena can produce a hot point that fuse the railgun and must be considered in armature and rail designing. This paper investigates the effect of armature geometry and dimensions on current density distribution, maximum value of current density, inductance gradient and normal force or normal pressure on armature. |
| Author(s): | M. S. Bayati, K. Amiri |
| File Type: | Journal Paper |
| Issue: | Volume: 30 Number: 9 Year: 2015 |
| Download Link: | Click here to download PDF File Size: 1417 KB |
| Title: | Tesla Transformer and its Response with Square Wave and Sinusoidal Excitations |
| Abstract: | This paper analyses the output of Tesla transformer from input defined as square wave and sine wave and its transfer function obtained from its equivalent circuit. The transfer function presented is analyzed in terms of the time, and the output is obtained when applying an input defined as a step and a sine function. When using square wave, the high gain obtained is proved that is due to a sum of responses obtained through positive and negative step that forms the square wave. However, the gain obtained when the excitation is a sine wave is higher than square wave excitation. Thus, in this paper is shown that the Tesla transformer works with sinusoidal excitation too, and present higher gain than square wave excitation, both higher than expected in classical transformer theory (turns ratio). All analysis presented were based in simulating operation using MATLAB® comparing with experimental data. |
| Author(s): | E. M. M. Costa |
| File Type: | Journal Paper |
| Issue: | Volume: 30 Number: 9 Year: 2015 |
| Download Link: | Click here to download PDF File Size: 681 KB |