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Title: ACES Journal October 2019 Cover
File Type: Journal Paper
Issue:Volume: 34      Number: 10      Year: 2019
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Title: ACES Journal October 2019 Front/Back Matter
File Type: Journal Paper
Issue:Volume: 34      Number: 10      Year: 2019
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Title: ACES Journal October 2019 Full
File Type: Journal Paper
Issue:Volume: 34      Number: 10      Year: 2019
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Title: A Compact Finite-Difference Frequency-Domain Method for Analysis of Microwave Transmission Lines with Rough Surface
Abstract: Accurate modeling of microwave transmission lines is very important in microwave communication and radar systems, especially at high frequencies. A compact finite-difference frequencydomain method (FDFD) is presented to analyze the propagation characteristics of microwave transmission lines with rough conductor surface. Equations in the Maxwell system are discretized with difference method in the cross-section of the microwave transmission line, and rough surface of microwave transmission lines is replaced by complex surface impedance from the conductivity Gradient Model. The eigen equations of the electromagnetic field components are formed and solved to obtain the propagation constants for a given frequency. The presented method reduces the computer storage effectively in ensuring simulation accuracy without the direct modeling for surface roughness, which can be applied in the modeling of complex microwave circuits.
Author(s): B. Huang, X. Wang
File Type: Journal Paper
Issue:Volume: 34      Number: 10      Year: 2019
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Title: A Design Method for Synthesizing a Dual-Passband FSS for Wi-Fi Using Equivalent Circuit Model
Abstract: In this letter, a dual-passband frequency selective surface (FSS) at Wi-Fi operation bands is presented. The proposed structure is implemented by two-dimensional periodic array of double square slots on single dielectric layer, which can be used to isolate the intensive care rooms of hospitals from insignificant signals, but supports Wi-Fi features, enabling doctors to acquire the patients’ health condition at any time. The design procedure is based on the equivalent circuit method (ECM) combined with the genetic algorithm (GA) curve-fitting, which aims at providing the initial dimension parameters of FSS. Ultimately, the calculated results from the ECM are compared with the numerical results of the HFSS optimization, and the measured frequency response of the fabricated FSS covers all the Wi-Fi frequency bands, which verify the reliability of this design.
Author(s): Y. Xu, M. He
File Type: Journal Paper
Issue:Volume: 34      Number: 10      Year: 2019
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Title: An Efficient Numerical Model for the Radiation Analysis of Microstrip Patch Antennas
Abstract: An accurate integral equation method based on quasi-static relationship (QSR), thin dielectric sheet (TDS) method and high-order hierarchical Legendre (HOHL) basis function is proposed in this paper for fast analysis of microstrip antennas radiation problems. This technique employs the QSR of the current on the parallel plate capacitor to describe the field continuity boundary condition and to embody the tight coupling between the radiation patch, the ground plane and the substrate of microstrip antenna. The frequency offset problem of conventional VSIE can be effectively eliminated. Moreover, combined with the TDS and the HOHL basis function, the proposed model can provide high accuracy in input impedance and far-field performance with faster convergence speed and lower computational cost. Numerical results are presented to show the accuracy and efficiency of the proposed method.
Author(s): L. Liu, Z. Nie
File Type: Journal Paper
Issue:Volume: 34      Number: 10      Year: 2019
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Title: High Power Dielectric Reflectarray Antenna using 3D Printing Technology
Abstract: A high power dielectric reflectarray with a continuous variation of the effective permittivity of a dielectric slab is proposed, based on a cross-shaped element implemented in the slab. The improved method used to retrieve the effective permittivity from the S parameters shows that a continuously changing effective relative permittivity from 1.25 to 3.4 can be reached by adjusting the notch width of the cross-shape, yielding a full 360° range of phase shifts at 9.3GHz. An array of 10×10 elements is designed to verify the radiation properties.Simulation results show that a main beam direction of 25° and a maximum gain of 19.5dB can be realized at the 9.3GHz center frequency. The power capacity of the element reaches 371kW, opening the possibility of high power applications. Fused Deposition Modelling (FDM), a specific approach in 3D printing, was employed for the fabrication of a prototype. This technology significantly reduces material cost and manufacturing time.
Author(s): B. Huang, Q. Qiang, G. A. E. Vandenbosch
File Type: Journal Paper
Issue:Volume: 34      Number: 10      Year: 2019
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Title: Optical Crosstalk Improvement in Ring Resonator Based Add/Drop Multiplexers Using Controllable Reflectivity
Abstract: In this paper, the topic of optical signal integrity is approached by studying crosstalk suppression in ring resonator based optical Add/Drop Multiplexers (OADM). The resonance splitting induced by surface corrugation is exploited to enhance signal integrity by increasing the crosstalk suppression bandwidth compared to that of a smooth-walled resonator. Sidewall roughness in silicon-on-insulator waveguides is studied using Coupled Mode Theory (time and space domain CMT). An analytical model of a corrugated ring resonator is presented, which is then exploited to estimate the spectral response of the different ports. Verification against results generated from full-wave electromagnetic numerical modeling of a randomized corrugated ring is performed. The analysis then examines the performance of an OADM with controllable reflectivity resulting from a predefined corrugation of sidewall. Gratings have been successfully used in optical filters; this paper proposes the use of a grating in an OADM, giving more controlled roughness. A grating-assisted design of a single ring OADM with 28 GHz crosstalk suppression bandwidth is presented. This bandwidth supports the dropping of 10 Gbps signals with mitigated crosstalk levels and improved signal integrity.
Author(s): R. D. Mansoor, A. P. Duffy
File Type: Journal Paper
Issue:Volume: 34      Number: 10      Year: 2019
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Title: Design of a Thin Broadband Metamaterial Absorber Based on Resistance Frequency Selective Surface
Abstract: A thin broadband metamaterial absorber with Resistive Frequency Selective Surface (RFSS) is presented. The absorber maintains a good performance over a broad operating frequency band with low profile. It is designed by a class of periodic artificial electromagnetic structures and the unit cell of the proposed absorber is composed of resistively loaded square loops with different sizes. By combining multiple resonant square loops (MRSL) of different geometries on a single layer structure, the absorption spectrum is greatly expanded. Simulation results show that the absorption coefficient is greater than 85% from 7.9GHz to 18.9GHz, while the thickness of the whole structure is 0.1λ (the free space wavelength) at the lowest operation frequency. A prototype was fabricated and measured in an anechoic chamber to validate the proposed design method. Favorable agreement among the full-wave simulation result and measurement result was achieved.
Author(s): P. Zhou, Q. Huang, L. Ji, X. Shi
File Type: Journal Paper
Issue:Volume: 34      Number: 10      Year: 2019
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Title: RCS Reduction and Radiation Improvement of a Circularly Polarized Patch Antenna using AMC Structures
Abstract: Based on a polarization-dependent artificial magnetic conductor (AMC), a windmill-formed reflector is designed and applied to a circularly polarized patch antenna to reduce the radar cross section (RCS) and to improve the radiation properties of the antenna at the same time. Simulation and measurement results show that the proposed antenna bears an in-band RCS reduction for 10dB over a bandwidth of 30% for both polarizations. The 3dB axial ratio (AR) bandwidth is extended largely with gain improved compared with the reference antenna.
Author(s): W. Song, W.-B. Zheng, Z.-J. Han, X.-Q. Sheng
File Type: Journal Paper
Issue:Volume: 34      Number: 10      Year: 2019
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Title: High Gain Circularly Polarized X-shaped Aperture Coupled Antenna for WLAN Applications
Abstract: This paper presents a new high gain compact aperture-coupled circularly polarized antenna for WLAN applications. The proposed antenna comprises an asymmetric X-shaped slot etched on a circular patch and fed through the coupling between an annular slot and a microstrip line. The circular polarization is mainly due to the asymmetrical crossed-slots, respecting the angle of 450 between its two arms. The antenna with overall size of 60 × 60 × 5.83 mm3 has a measured 10-dB impedance bandwidth of 36%, a 3-dB axial ratio bandwidth of 3.47% (5.67–5.87 GHz) and 1-dB gain bandwidth of 19.5% (4.85-5.90 GHz) with a peak gain of 8.65 dBi. To validate the simulated results, a prototype was fabricated, and good agreement between simulations and measurements has been accomplished.
Author(s): M. A. Meriche, A. Messai, T. A. Denidni, H. Attia
File Type: Journal Paper
Issue:Volume: 34      Number: 10      Year: 2019
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Title: Broadband Circularly Polarized Antennas with Improved Gain
Abstract: A broadband circularly polarized (CP) antenna with improved gain is proposed. The broadband CP antenna consists of two folded off-center-fed dipoles. Due to the two-dipole configuration, the antenna gain is improved by almost 2 dB. It is shown by simulation and experiment that the broadband CP antenna achieves an impedance bandwidth of 52% (1.71-2.89 GHz) for reflection coefficient<-15 dB and an axial ratio (AR) bandwidth of 45% (1.75-2.73 GHz) for AR<3 dB. The average antenna gain is about 10 dBi. A differentiallyfed broadband CP antenna is also developed. Simulated and measured results show that the differentially-fed CP antenna fulfills an impedance bandwidth of 60% (1.53-2.83 GHz) for differential reflection coefficient <-15 dB and a 3-dB AR bandwidth of 44% (1.76-2.75 GHz). The average antenna gain is about 10 dBi. The gain-improved broadband CP antennas feature a simple planar configuration, which are suitable for applications in satellite/wireless communications.
Author(s): M. Xiao, H. Liu, Y. Cui
File Type: Journal Paper
Issue:Volume: 34      Number: 10      Year: 2019
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Title: Effects of Array's Digital Beam Forming and Digital Polarization Synthesis Sequence on the Synthesis Results
Abstract: A polarized beamforming method of antenna array is addressed here. In this method, digital polarization synthesis (DPS) and digital beam forming (DBF) are processed separately in sequence. It synthesizes linearly-polarized antenna array into a circularlypolarized antenna whose main beam can scan in azimuth direction. The synthesis process and how the sequence affect the results are both expressed. It can be derived that with DPS-DBF (DPS first and DBF next), the beam is more smooth and has a better circular polarization in the main beam. This method can be used in solar radio observations and other systems that require wideband polarization measurements.
Author(s): J. Zhang, L. Song, Q. Du, Y. Chen
File Type: Journal Paper
Issue:Volume: 34      Number: 10      Year: 2019
Download Link:Click here to download PDF     File Size: 1972 KB

Title: A Multiband Dual-Antenna System for MIMO Operation in Mobile Terminals
Abstract: A multiband dual-antenna design for multiinput- multi-output (MIMO) operation in mobile terminals is presented. The proposed dual-antenna system is composed of two symmetric antenna elements, and each of them consists of one driven branch and one parasitic branch. The dual-antenna system uses a simple decoupling structure to reduce the mutual coupling between two antenna elements. The impedance bandwidth with active |S11|≤-6dB covers two frequency bands of 700-960 and 1710-2690 MHz, and the isolation between the two antenna elements is better than 10dB within most of the operating bands. The envelop correlation coefficient, mean effective gain, diversity gain, and channel capacity are calculated exhaustively based on the three-dimensional radiation patterns. The results show that the antenna system has good diversity performance, which makes it suitable for MIMO operation in mobile terminals.
Author(s): Z. An, M. He
File Type: Journal Paper
Issue:Volume: 34      Number: 10      Year: 2019
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Title: Design of Pin Loaded Reconfigurable Patch Antenna for Wireless Communications
Abstract: The design and performance analysis of a single fed reconfigurable patch antenna for circular polarization is presented. The patch has a square shaped slot etched on it. Four ultra-miniature diode switches are placed at appropriate positions to bridge the gap in the slot regions and are used to switch the nature of polarization between left-hand circular polarization (LHCP) and right-hand circular polarization (RHCP). The antenna achieves an impedance bandwidth (S11 ≤ -10dB) between 2.34 GHz to 2.4 GHz (2.53%) with a center operating frequency of 2.37 GHz. The surface current distributions on the radiating patch along with its corresponding radiation patterns measured at the operating frequency are plotted. The antenna achieves an axial ratio beam width (AR ≤ 3dB) of -25⁰ to 50⁰ for left-hand circular polarization and -40⁰ to 45⁰ for righthand circular polarization. Measured radiation pattern results show the antenna has a good cross-polarization isolation of -16.2 dB for RHCP configuration and -16.54 dB for LHCP configurations and hence the antenna is suitable for modern wireless applications.
Author(s): M. Saravanan, M. J. S. Rangachar
File Type: Journal Paper
Issue:Volume: 34      Number: 10      Year: 2019
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Title: Frequency Reconfigurable Fractal CPW-Fed Antennas Designed for Telecommunication Applications
Abstract: A frequency reconfigurable fractal antenna for wireless communication application is presented in this paper. Three RF switches are incorporated into the antenna design to achieve frequency reconfigurability. The proposed antenna is designed and simulated using the HFSS code and then fabricated. The experimental results confirm the numerical simulation and demonstrate that integrating the RF switches improves the antenna flexibility and enables us to switch the antenna from single-band to dual-band as well as to a multi-band state with minimal design complexity and high degree of miniaturization.
Author(s): S. Mehri, I. Rouissi, H. Rmili, B. Hakim, R. Mittra
File Type: Journal Paper
Issue:Volume: 34      Number: 10      Year: 2019
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Title: An Experimental Performance Investigation of an Ultra-Wideband Directional Antenna in the Microwave Imaging of Breast Cancer Tumor
Abstract: The purpose of this study is testing the performance and success of a compact-sized, ultrawideband and directional printed circular monopole antenna proposed in a previous study for detection of the small breast cancer tumors. For this aim, simple but basic experimental studies of the radar-based ultra-wideband microwave measurement system are presented. In the measurements, different breast phantoms that have low dielectric constant materials representing the fat tissue and high dielectric constant object representing the tumor are formed and used. The object is located at different positions and the reflected signals are observed. The monostatic system which uses the same antenna to perform both the transmitting and receiving task of the signals is preferred in the study. According to the measured frequency domain signals, the reflected energy increases when the tumor is present. According to the amplitude and phase of the time domain signals, the presence, position and size of the tumor are inferenced. In order to provide more clear information about the tumor, a sample image is also created by implementing delay-and-sum algorithm. Furthermore, specific absorption rate of the breast is discussed. In summary, the performance of the antenna is valid for using in the radar-based ultrawideband microwave imaging with respect to its features of the size, bandwidth, directivity, and beamwidth.
Author(s): A. R. Celik, M. B. Kurt, S. Helhel
File Type: Journal Paper
Issue:Volume: 34      Number: 10      Year: 2019
Download Link:Click here to download PDF     File Size: 1980 KB

Title: Design and Implementation of Frequency Selective Radome for X-Band Applications
Abstract: A triple layer X-band FSS is designed and its reflection and transmission characteristics are explored for normal/oblique incidence. The proposed planar FSS is confirmed by simulation and measurement results. Then, by using the X-band FSS, a novel X-band radome is designed. Its reflection and transmission characteristics are investigated for in-band and out-of band frequencies by integrating an ultra-wide band antenna. A comparison of radiation patterns at selected frequencies for cases with and without radome is examined. Adaptation of radome to the antenna is achieved without significant reduction in radiation performance at the design frequency of FSS.
Author(s): C. Topcuoglu, C. D. Erbas, N. T. Tokan
File Type: Journal Paper
Issue:Volume: 34      Number: 10      Year: 2019
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Title: Development of a High Gain, Dual-Band and Two-Layer Miniaturized Microstrip Antenna for 5.8 GHz ISM and 10 GHz X-Band Applications
Abstract: In this study, it is explained how to increase the gain of a two-layer stacked miniaturized microstrip patch antenna (MPA) operating at 5.8 GHz and 10 GHz step by step by combining several different methods used in the literature for performance improvement of MPAs. A commonly used FR4 substrate material was preferred to design and produce the antenna. For electromagnetic modeling of the prototype structure, numerical analysis, and optimization, ANSYS HFSS was used. The performance of the proposed antenna was evaluated in terms of return loss (RL), surface current distribution, radiation patterns and gain/directivity. To confirm the study, the simulation results were compared with the measurements taken over the antenna prototype and good agreement has been achieved. The peak gain values of the proposed antenna at 5.8 GHz and 10 GHz are obtained as 4.11 dBi and 7.15 dBi, respectively.
Author(s): I. Atas, T. Abbasov, M. B. Kurt
File Type: Journal Paper
Issue:Volume: 34      Number: 10      Year: 2019
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Title: Electrical Characterization of Concrete Using the Parallel Plate Capacitor Method
Abstract: This article describes the measurement of the complex dielectric constant of pure concrete and a brick wall, in the frequency range up to 2 MHz, with a view towards more accurate material description in electromagnetic simulations. The measurement system is based on the use of the materials under test as the dielectric material placed inside a parallel plate capacitor, in series with an external known fixed resistor. The theory behind the measurement is covered, and the results of both real and imaginary relative dielectric constants for both materials are presented. Finally, an electromagnetic simulation showing the shielding effectiveness of a hollow box made of a brick wall is presented, using the measured data in comparison with data from a commercial simulator database.
Author(s): M. B. Perotoni, M. S. Vieira, K. M. dos Santos, D. B. Almeida
File Type: Journal Paper
Issue:Volume: 34      Number: 10      Year: 2019
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Title: Six-Channel Diplexer using Stub-Loaded Stepped Impedance Resonators
Abstract: In this paper, a compact six-channel diplexer with low insertion loss and high isolation level is presented. The diplexer consists of two tri-band bandpass filters (BPFs), two meander transmission lines and hookshaped feeding lines. The BPFs are designed based on stub-loaded stepped impedance resonators (SLSIRs). Based on even- and odd-mode (EOM) analysis of the resonator, there are two resonant modes that operate at the same frequency. For splitting the two modes, stubstub coupling is employed here. The combination of the two BPFs is implemented by utilizing two meander transmission lines as the impedance matching network. Finally the proposed diplexer operating at 1.46/1.74/2.96 GHz (for Load 1) and 0.89/1.15/2.40 GHz (for Load 2) is fabricated and measured. A good agreement between simulated and measured results evidently validates the proposed diplexer.
Author(s): J. Liu, T. Su, H. Lv, L. Lin, B. Wu
File Type: Journal Paper
Issue:Volume: 34      Number: 10      Year: 2019
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Title: A Diplexer based on Hybrid Cavity and Microstrip Structure
Abstract: This paper presents a high selective diplexer with hybrid filters, which is composed by dual-mode microstrip resonators with metallic coaxial shielding cases of RF module. By utilizing vertical space above microstrip circuits which greatly saves space, an additional pair of transmission pole and zero are hereby added in the passband and stopband, respectively. The proposed structure provides high quality-factors to enhance frequency selectivity. For demonstration, a diplexer prototype is designed and fabricated at the center frequencies (CF) of 2.40 and 3.45 GHz with a 3-dB passband bandwidth of 200 MHz. The measured insertion losses (IL) are 1.45 dB and 1.61 dB in the lower and upper passbands respectively. The output isolation between two channels is measured greater than 32 dB.
Author(s): J. Shu, Y. Zhang
File Type: Journal Paper
Issue:Volume: 34      Number: 10      Year: 2019
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Title: A Dual Band Circularly Polarized Rectenna for RF Energy Harvesting Applications
Abstract: This paper presents a dual band rectenna for RF energy harvesting applications. The receiving slot antenna has a single feed configuration with a coplanar waveguide (CPW) structure. A grounded-L strip is employed for circular polarized (CP) radiation. A stepped impedance matching stub is used to enhance the coupling between the feed line, inverted L-strip, and the slot. An asymmetric U-shaped strip is embedded near the upper right corner of the slot as a perturbed element. This asymmetric U-shaped strip is a key component to excite the required phase perturbation to produce a CP radiation. The antenna operates in the WiFi frequency bands of 2.45 GHz (IEEE 802.11b&g) and 5 GHz (IEEE 802.11a/h/j/n/ac/ax WLAN system). A dual band voltage doubler rectifier has been designed and implemented for RF to DC conversion. The impedance matching network for this rectifier is based on a П-model dual band impedance transformer that is optimized to match two unequal complex loads at two operational frequencies.
Author(s): O. M. Dardeer, H. A. Elsadek, E. A. Abdallah, H. M. Elhennawy
File Type: Journal Paper
Issue:Volume: 34      Number: 10      Year: 2019
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Title: A Novel Low Temperature Process for Microwave Dielectric Ceramics Metallization
Abstract: This research proposes a novel low temperature process for microwave dielectric ceramics metallization with laser patterning and electroless copper plating. The process temperature of the proposed process is less than 50 °C, which is much lower than typical metallization technology, such as Low Temperature Cofired Ceramics (LTCC) and Direct Bond Copper (DBC). Compared with LTCC and DBC, the proposed low temperature process can significantly reduce energy consumption, cut cost for cooling equipment, and offer smaller metal pattern variations. The measurement results demonstrate the line width error and the line position precision are all within ±50 μm. Moreover, this proposed process produces no short circuit or incomplete metallization in the walls of the holes. The measurement and simulation results demonstrate the manufactured samples meet the bandpass filter design specifications. Therefore, the proposed low temperature process is practical and adequate for producing microwave dielectric ceramics.
Author(s): J.-J. Lin, C.-I. Lin, T.-H. Kao, M.-C. Huang
File Type: Journal Paper
Issue:Volume: 34      Number: 10      Year: 2019
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Title: Coupling of 3D Analytical Calculation and PSO for the Identification of Magnet Parameters used in Magnetic Separation
Abstract: In this work, the identification of the residual magnetic flux density of NdFeB permanent magnet, used in a drum magnetic separator, is performed. This identification problem has been formulated as an inverse optimization problem and solved using the Particle Swarm Optimization (PSO) method. For fast calculations, flux densities are computed using a 3D analytical method and the obtained results are compared with measurements.
Author(s): M. Ouili, R. Mehasni, M. Feliachi, H. Allag, H. R. E. H. Bouchekara, G. Berthiau, M. E. H. Latreche
File Type: Journal Paper
Issue:Volume: 34      Number: 10      Year: 2019
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Title: Optimized Semi-implicit Methods for Modeling Cardiac Propagation
Abstract: Computer simulation of cardiac electrophysiology is now considered a powerful tool for exploring the causes of cardiac arrhythmias. Cardiac electric propagation has been studied using the monodomain model to describe wave propagation of action potential in the heart. The governing nonlinear reaction-diffusion partial differential equation is solved with the semi-implicit (implicit-explicit) method that does not have the stability limit of the explicit timestepping scheme. Both first order and second order semi-implicit techniques for temporal discretization are considered in this paper. Second order finite difference technique is used to discretize the spatial derivatives. An explicit finite difference scheme with 512×512 nodes and 0.1 μs time step is used as the benchmark for error calculation. APPSPACK, a parallel pattern search optimization software, is used to obtain the optimal semi-implicit parameters that give the lowest root-meansquare error. Results are presented for the semi-implicit techniques with or without the operator split or protective zone method. They demonstrate that the optimized second order semi-implicit method gives the best overall performance.
Author(s): R. Khan, K. T. Ng
File Type: Journal Paper
Issue:Volume: 34      Number: 10      Year: 2019
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