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Publisher: Hindawi   (Total: 269 journals)

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Showing 1 - 200 of 269 Journals sorted alphabetically
Abstract and Applied Analysis     Open Access   (Followers: 3, SJR: 0.512, h-index: 32)
Active and Passive Electronic Components     Open Access   (Followers: 7, SJR: 0.157, h-index: 15)
Advances in Acoustics and Vibration     Open Access   (Followers: 29, SJR: 0.259, h-index: 6)
Advances in Agriculture     Open Access   (Followers: 7)
Advances in Artificial Intelligence     Open Access   (Followers: 16)
Advances in Astronomy     Open Access   (Followers: 39, SJR: 0.351, h-index: 17)
Advances in Bioinformatics     Open Access   (Followers: 20, SJR: 0.421, h-index: 8)
Advances in Chemistry     Open Access   (Followers: 15)
Advances in Civil Engineering     Open Access   (Followers: 36, SJR: 0.338, h-index: 8)
Advances in Condensed Matter Physics     Open Access   (Followers: 9, SJR: 0.248, h-index: 10)
Advances in Decision Sciences     Open Access   (Followers: 5, SJR: 0.231, h-index: 6)
Advances in Fuzzy Systems     Open Access   (Followers: 5, SJR: 0.258, h-index: 7)
Advances in Hematology     Open Access   (Followers: 10, SJR: 0.892, h-index: 18)
Advances in High Energy Physics     Open Access   (Followers: 19, SJR: 0.892, h-index: 19)
Advances in Human-Computer Interaction     Open Access   (Followers: 21, SJR: 0.439, h-index: 9)
Advances in Materials Science and Engineering     Open Access   (Followers: 32, SJR: 0.263, h-index: 11)
Advances in Mathematical Physics     Open Access   (Followers: 5, SJR: 0.332, h-index: 10)
Advances in Medicine     Open Access   (Followers: 2)
Advances in Meteorology     Open Access   (Followers: 18, SJR: 0.498, h-index: 10)
Advances in Multimedia     Open Access   (Followers: 2, SJR: 0.191, h-index: 10)
Advances in Nonlinear Optics     Open Access   (Followers: 6)
Advances in Numerical Analysis     Open Access   (Followers: 4)
Advances in Operations Research     Open Access   (Followers: 12, SJR: 0.343, h-index: 7)
Advances in Optical Technologies     Open Access   (Followers: 3, SJR: 0.283, h-index: 16)
Advances in OptoElectronics     Open Access   (Followers: 5, SJR: 0.973, h-index: 16)
Advances in Orthopedics     Open Access   (Followers: 10)
Advances in Pharmacological Sciences     Open Access   (Followers: 7, SJR: 0.695, h-index: 13)
Advances in Physical Chemistry     Open Access   (Followers: 10, SJR: 0.297, h-index: 7)
Advances in Power Electronics     Open Access   (Followers: 28, SJR: 0.26, h-index: 6)
Advances in Preventive Medicine     Open Access   (Followers: 6)
Advances in Public Health     Open Access   (Followers: 23)
Advances in Tribology     Open Access   (Followers: 12, SJR: 0.267, h-index: 6)
Advances in Urology     Open Access   (Followers: 9, SJR: 0.629, h-index: 16)
Advances in Virology     Open Access   (Followers: 7, SJR: 1.04, h-index: 12)
AIDS Research and Treatment     Open Access   (Followers: 3, SJR: 1.125, h-index: 14)
Analytical Cellular Pathology     Open Access   (Followers: 2, SJR: 0.334, h-index: 12)
Anatomy Research Intl.     Open Access   (Followers: 2)
Anemia     Open Access   (Followers: 4, SJR: 0.991, h-index: 11)
Anesthesiology Research and Practice     Open Access   (Followers: 12, SJR: 0.513, h-index: 12)
Applied and Environmental Soil Science     Open Access   (Followers: 18, SJR: 0.53, h-index: 9)
Applied Bionics and Biomechanics     Open Access   (Followers: 8, SJR: 0.23, h-index: 13)
Applied Computational Intelligence and Soft Computing     Open Access   (Followers: 12)
Archaea     Open Access   (Followers: 3, SJR: 1.248, h-index: 27)
Arthritis     Open Access   (Followers: 5)
Autism Research and Treatment     Open Access   (Followers: 29)
Autoimmune Diseases     Open Access   (Followers: 3, SJR: 0.909, h-index: 17)
Behavioural Neurology     Open Access   (Followers: 9, SJR: 0.696, h-index: 34)
Biochemistry Research Intl.     Open Access   (Followers: 6, SJR: 1.085, h-index: 17)
Bioinorganic Chemistry and Applications     Open Access   (Followers: 9, SJR: 0.286, h-index: 19)
BioMed Research Intl.     Open Access   (Followers: 6, SJR: 0.725, h-index: 59)
Biotechnology Research Intl.     Open Access   (Followers: 2)
Bone Marrow Research     Open Access   (Followers: 2)
Canadian J. of Gastroenterology & Hepatology     Open Access   (Followers: 5, SJR: 0.856, h-index: 53)
Canadian J. of Infectious Diseases and Medical Microbiology     Open Access   (Followers: 5, SJR: 0.409, h-index: 25)
Canadian Respiratory J.     Open Access   (Followers: 1, SJR: 0.503, h-index: 42)
Cardiology Research and Practice     Open Access   (Followers: 8, SJR: 0.941, h-index: 17)
Case Reports in Anesthesiology     Open Access   (Followers: 10)
Case Reports in Cardiology     Open Access   (Followers: 3)
Case Reports in Critical Care     Open Access   (Followers: 9)
Case Reports in Dentistry     Open Access   (Followers: 5)
Case Reports in Dermatological Medicine     Open Access   (Followers: 2)
Case Reports in Emergency Medicine     Open Access   (Followers: 15)
Case Reports in Endocrinology     Open Access   (SJR: 0.326, h-index: 1)
Case Reports in Gastrointestinal Medicine     Open Access   (Followers: 3)
Case Reports in Genetics     Open Access   (Followers: 1)
Case Reports in Hematology     Open Access   (Followers: 5)
Case Reports in Hepatology     Open Access   (Followers: 1)
Case Reports in Immunology     Open Access   (Followers: 4)
Case Reports in Infectious Diseases     Open Access   (Followers: 6)
Case Reports in Medicine     Open Access   (Followers: 3)
Case Reports in Nephrology     Open Access   (Followers: 4)
Case Reports in Neurological Medicine     Open Access   (Followers: 1)
Case Reports in Obstetrics and Gynecology     Open Access   (Followers: 10)
Case Reports in Oncological Medicine     Open Access   (Followers: 2)
Case Reports in Ophthalmological Medicine     Open Access   (Followers: 4)
Case Reports in Orthopedics     Open Access   (Followers: 7)
Case Reports in Otolaryngology     Open Access   (Followers: 6)
Case Reports in Pathology     Open Access   (Followers: 5)
Case Reports in Pediatrics     Open Access   (Followers: 6)
Case Reports in Psychiatry     Open Access   (Followers: 12)
Case Reports in Pulmonology     Open Access   (Followers: 3)
Case Reports in Radiology     Open Access   (Followers: 8)
Case Reports in Rheumatology     Open Access   (Followers: 5)
Case Reports in Surgery     Open Access   (Followers: 11)
Case Reports in Transplantation     Open Access  
Case Reports in Urology     Open Access   (Followers: 8)
Case Reports in Vascular Medicine     Open Access  
Case Reports in Veterinary Medicine     Open Access   (Followers: 6)
Child Development Research     Open Access   (Followers: 17)
Chinese J. of Engineering     Open Access   (Followers: 2)
Chinese J. of Mathematics     Open Access  
Cholesterol     Open Access   (Followers: 1, SJR: 0.906, h-index: 12)
Complexity     Hybrid Journal   (Followers: 6, SJR: 0.526, h-index: 27)
Computational and Mathematical Methods in Medicine     Open Access   (Followers: 2, SJR: 0.415, h-index: 22)
Computational Intelligence and Neuroscience     Open Access   (Followers: 10, SJR: 0.232, h-index: 30)
Contrast Media & Molecular Imaging     Open Access   (Followers: 3, SJR: 0.932, h-index: 34)
Critical Care Research and Practice     Open Access   (Followers: 10, SJR: 0.916, h-index: 14)
Current Gerontology and Geriatrics Research     Open Access   (Followers: 9, SJR: 0.8, h-index: 12)
Depression Research and Treatment     Open Access   (Followers: 14, SJR: 0.77, h-index: 11)
Dermatology Research and Practice     Open Access   (Followers: 3, SJR: 0.576, h-index: 15)
Diagnostic and Therapeutic Endoscopy     Open Access   (SJR: 0.651, h-index: 18)
Discrete Dynamics in Nature and Society     Open Access   (Followers: 5, SJR: 0.323, h-index: 24)
Disease Markers     Open Access   (Followers: 1, SJR: 0.774, h-index: 49)
Education Research Intl.     Open Access   (Followers: 21)
Emergency Medicine Intl.     Open Access   (Followers: 8)
Enzyme Research     Open Access   (Followers: 4, SJR: 0.457, h-index: 18)
Evidence-based Complementary and Alternative Medicine     Open Access   (Followers: 20, SJR: 0.615, h-index: 50)
Experimental Diabetes Research     Open Access   (Followers: 13, SJR: 1.591, h-index: 30)
Gastroenterology Research and Practice     Open Access   (Followers: 3, SJR: 0.664, h-index: 21)
Genetics Research Intl.     Open Access   (Followers: 1)
Geofluids     Open Access   (Followers: 5, SJR: 0.693, h-index: 38)
HPB Surgery     Open Access   (Followers: 5, SJR: 0.798, h-index: 22)
Infectious Diseases in Obstetrics and Gynecology     Open Access   (Followers: 6, SJR: 0.976, h-index: 34)
Interdisciplinary Perspectives on Infectious Diseases     Open Access   (Followers: 2, SJR: 0.763, h-index: 15)
Intl. J. of Aerospace Engineering     Open Access   (Followers: 70, SJR: 0.241, h-index: 6)
Intl. J. of Agronomy     Open Access   (Followers: 8, SJR: 0.223, h-index: 2)
Intl. J. of Alzheimer's Disease     Open Access   (Followers: 12, SJR: 1.193, h-index: 25)
Intl. J. of Analysis     Open Access  
Intl. J. of Analytical Chemistry     Open Access   (Followers: 22, SJR: 0.157, h-index: 2)
Intl. J. of Antennas and Propagation     Open Access   (Followers: 11, SJR: 0.385, h-index: 15)
Intl. J. of Biodiversity     Open Access   (Followers: 4)
Intl. J. of Biomaterials     Open Access   (Followers: 5, SJR: 0.485, h-index: 10)
Intl. J. of Biomedical Imaging     Open Access   (Followers: 4, SJR: 0.581, h-index: 23)
Intl. J. of Breast Cancer     Open Access   (Followers: 13)
Intl. J. of Cell Biology     Open Access   (Followers: 4, SJR: 2.658, h-index: 25)
Intl. J. of Chemical Engineering     Open Access   (Followers: 7, SJR: 0.361, h-index: 10)
Intl. J. of Chronic Diseases     Open Access   (Followers: 1)
Intl. J. of Computer Games Technology     Open Access   (Followers: 11, SJR: 0.213, h-index: 12)
Intl. J. of Corrosion     Open Access   (Followers: 11, SJR: 0.19, h-index: 7)
Intl. J. of Dentistry     Open Access   (Followers: 6, SJR: 0.558, h-index: 11)
Intl. J. of Differential Equations     Open Access   (Followers: 8, SJR: 0.363, h-index: 11)
Intl. J. of Digital Multimedia Broadcasting     Open Access   (Followers: 5, SJR: 0.144, h-index: 10)
Intl. J. of Electrochemistry     Open Access   (Followers: 8)
Intl. J. of Endocrinology     Open Access   (Followers: 3, SJR: 0.961, h-index: 24)
Intl. J. of Engineering Mathematics     Open Access   (Followers: 5)
Intl. J. of Food Science     Open Access   (Followers: 3)
Intl. J. of Forestry Research     Open Access   (Followers: 4)
Intl. J. of Genomics     Open Access   (Followers: 2, SJR: 0.721, h-index: 7)
Intl. J. of Hepatology     Open Access   (Followers: 4)
Intl. J. of Hypertension     Open Access   (Followers: 7, SJR: 0.823, h-index: 20)
Intl. J. of Inflammation     Open Access   (SJR: 0.876, h-index: 14)
Intl. J. of Mathematics and Mathematical Sciences     Open Access   (Followers: 3, SJR: 0.346, h-index: 27)
Intl. J. of Medicinal Chemistry     Open Access   (Followers: 6)
Intl. J. of Microbiology     Open Access   (Followers: 5, SJR: 1.006, h-index: 18)
Intl. J. of Navigation and Observation     Open Access   (Followers: 20, SJR: 0.411, h-index: 7)
Intl. J. of Nephrology     Open Access   (Followers: 1, SJR: 0.926, h-index: 14)
Intl. J. of Optics     Open Access   (Followers: 7, SJR: 0.262, h-index: 7)
Intl. J. of Otolaryngology     Open Access   (Followers: 3)
Intl. J. of Pediatrics     Open Access   (Followers: 5)
Intl. J. of Peptides     Open Access   (Followers: 4, SJR: 0.73, h-index: 16)
Intl. J. of Photoenergy     Open Access   (Followers: 2, SJR: 0.348, h-index: 28)
Intl. J. of Plant Genomics     Open Access   (Followers: 4, SJR: 1.578, h-index: 20)
Intl. J. of Polymer Science     Open Access   (Followers: 24, SJR: 0.265, h-index: 11)
Intl. J. of Population Research     Open Access   (Followers: 2)
Intl. J. of Reconfigurable Computing     Open Access   (SJR: 0.182, h-index: 8)
Intl. J. of Reproductive Medicine     Open Access   (Followers: 4)
Intl. J. of Rheumatology     Open Access   (Followers: 4, SJR: 1.015, h-index: 18)
Intl. J. of Rotating Machinery     Open Access   (Followers: 2, SJR: 0.402, h-index: 19)
Intl. J. of Spectroscopy     Open Access   (Followers: 8)
Intl. J. of Stochastic Analysis     Open Access   (Followers: 4, SJR: 0.234, h-index: 19)
Intl. J. of Surgical Oncology     Open Access   (Followers: 1, SJR: 0.753, h-index: 11)
Intl. J. of Telemedicine and Applications     Open Access   (Followers: 4, SJR: 0.757, h-index: 14)
Intl. J. of Vascular Medicine     Open Access   (SJR: 0.865, h-index: 16)
Intl. J. of Zoology     Open Access   (Followers: 2, SJR: 0.389, h-index: 8)
Intl. Scholarly Research Notices     Open Access   (Followers: 205)
ISRN Astronomy and Astrophysics     Open Access   (Followers: 7)
J. of Addiction     Open Access   (Followers: 12)
J. of Advanced Transportation     Hybrid Journal   (Followers: 12, SJR: 0.911, h-index: 24)
J. of Aging Research     Open Access   (Followers: 7, SJR: 1.259, h-index: 23)
J. of Analytical Methods in Chemistry     Open Access   (Followers: 1, SJR: 0.296, h-index: 13)
J. of Applied Chemistry     Open Access   (Followers: 4)
J. of Applied Mathematics     Open Access   (Followers: 2, SJR: 0.341, h-index: 22)
J. of Biomedical Education     Open Access   (Followers: 3)
J. of Blood Transfusion     Open Access   (Followers: 2)
J. of Botany     Open Access   (Followers: 3, SJR: 0.101, h-index: 2)
J. of Cancer Epidemiology     Open Access   (Followers: 7, SJR: 1.427, h-index: 12)
J. of Chemistry     Open Access   (Followers: 5, SJR: 0.225, h-index: 11)
J. of Combustion     Open Access   (Followers: 19, SJR: 0.27, h-index: 8)
J. of Complex Analysis     Open Access   (Followers: 3)
J. of Computer Networks and Communications     Open Access   (Followers: 5, SJR: 0.257, h-index: 8)
J. of Construction Engineering     Open Access   (Followers: 7)
J. of Control Science and Engineering     Open Access   (Followers: 1, SJR: 0.299, h-index: 9)
J. of Diabetes Research     Open Access   (Followers: 11, SJR: 1.024, h-index: 13)
J. of Drug Delivery     Open Access   (Followers: 8, SJR: 4.523, h-index: 2)
J. of Electrical and Computer Engineering     Open Access   (Followers: 9, SJR: 0.225, h-index: 10)
J. of Energy     Open Access   (Followers: 2)
J. of Engineering     Open Access  
J. of Environmental and Public Health     Open Access   (Followers: 17, SJR: 1.136, h-index: 16)
J. of Food Quality     Hybrid Journal   (Followers: 7, SJR: 0.497, h-index: 30)
J. of Function Spaces     Open Access   (SJR: 0.414, h-index: 10)
J. of Geological Research     Open Access   (Followers: 2)
J. of Healthcare Engineering     Open Access   (Followers: 3, SJR: 0.345, h-index: 10)
J. of Immunology Research     Open Access   (Followers: 10, SJR: 1.346, h-index: 41)
J. of Lipids     Open Access  
J. of Marine Biology     Open Access   (Followers: 16)
J. of Materials     Open Access  
J. of Mathematics     Open Access  
J. of Nanomaterials     Open Access   (Followers: 2, SJR: 0.383, h-index: 24)
J. of Nanoscience     Open Access  
J. of Nanotechnology     Open Access   (Followers: 7, SJR: 0.283, h-index: 9)

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Journal Cover International Journal of Antennas and Propagation
  [SJR: 0.385]   [H-I: 15]   [11 followers]  Follow
  This is an Open Access Journal Open Access journal
   ISSN (Print) 1687-5869 - ISSN (Online) 1687-5877
   Published by Hindawi Homepage  [269 journals]
  • Circularly Polarized Dielectric Resonator Antenna Arrays with Fractal
           Cross-Slot-Coupled DRA Elements

    • Abstract: In the design of circularly polarized (CP) dielectric resonator antenna (DRA) arrays, the regular-shaped DRAs with simple feeding configurations are mostly used as array elements to make the design procedure more efficient. However, such array element DRA usually achieves only about 6% axial ratio (AR) bandwidth. In this paper, a CP DRA element coupled by a fractal cross-slot which can radiate efficiently and excite the rectangular DRA simultaneously is considered. By adjusting the dimensions of the fractal cross-slot properly, the resonances of the fractal cross-slot and the dielectric resonator can be merged to obtain a wider AR bandwidth. Based on the proposed fractal cross-slot-coupled CP DRA element, two different CP DRA arrays are designed: a wideband CP DRA array and a low-sidelobe-level (SLL) CP DRA array. The designed DRA arrays are fabricated and measured, and structures and performances of the arrays are presented and discussed.
      PubDate: Tue, 14 Nov 2017 00:00:00 +000
  • Exploiting Microwave Imaging Methods for Real-Time Monitoring of Thermal

    • Abstract: Microwave thermal ablation is a cancer treatment that exploits local heating caused by a microwave electromagnetic field to induce coagulative necrosis of tumor cells. Recently, such a technique has significantly progressed in the clinical practice. However, its effectiveness would dramatically improve if paired with a noninvasive system for the real-time monitoring of the evolving dimension and shape of the thermally ablated area. In this respect, microwave imaging can be a potential candidate to monitor the overall treatment evolution in a noninvasive way, as it takes direct advantage from the dependence of the electromagnetic properties of biological tissues from temperature. This paper explores such a possibility by presenting a proof of concept validation based on accurate simulated imaging experiments, run with respect to a scenario that mimics an ex vivo experimental setup. In particular, two model-based inversion algorithms are exploited to tackle the imaging task. These methods provide independent results in real-time and their integration improves the quality of the overall tracking of the variations occurring in the target and surrounding regions.
      PubDate: Thu, 09 Nov 2017 00:00:00 +000
  • Design of Active Frequency Selective Surface with Curved Composite
           Structures and Tunable Frequency Response

    • Abstract: We present an active frequency selective surface (AFSS) consisting of a curved composite structure that provides structural stability and robustness. The proposed structure can operate on either the C-band (OFF state) or X-band (ON state) by controlling the PIN diode located between the cross-shaped loop and the inductive stub on the surface. Moreover, it minimizes parasitic couplings through grid-type on/off bias circuits and via holes. Thus, the AFSS guarantees isolation from the unit cell, which is a downside of a previous control technique called reconfigurable frequency selective surface. We analyzed the impact of composite structures and the three-dimensional shape on the AFSS transmission with a foam-core sandwich structure, which is light and mechanically strong, by considering conditions of a real application environment.
      PubDate: Thu, 09 Nov 2017 00:00:00 +000
  • Iterative Full-Wave Analysis of Mandelbrot-Inspired Fractal Patch Antenna
           on Textile Substrate for UWB Applications

    • Abstract: This work presents the analysis of monopole microstrip antennas with truncated ground plane and patch geometry inspired on the Mandelbrot fractal curve for applications in UWB systems. The proposed antenna geometry is analyzed using the Wave Concept Iterative Procedure (WCIP), a full-wave method. Results for the proposed antenna operating frequency, bandwidth, VSWR, gain, and radiation pattern are obtained and discussed. The WCIP results are compared with simulation results provided by HFSS software, for validation purpose. In addition, a prototype antenna is built and measured. A good match between WCIP theoretical and simulation, HFSS simulation, and measurement results is observed for the antenna frequency response.
      PubDate: Tue, 07 Nov 2017 05:58:05 +000
  • Modelling Scattering of Electromagnetic Waves in Layered Media: An
           Up-to-Date Perspective

    • Abstract: This paper addresses the subject of electromagnetic wave scattering in layered media, thus covering the recent progress achieved with different approaches. Existing theories and models are analyzed, classified, and summarized on the basis of their characteristics. Emphasis is placed on both theoretical and practical application. Finally, patterns and trends in the current literature are identified and critically discussed.
      PubDate: Sun, 05 Nov 2017 07:55:42 +000
  • Estimating Direction of Arrival by Using Two-Dimensional State-Space
           Balance Method

    • Abstract: A study of a two-dimensional state-space balance (2D SSB) method for estimating direction of arrival (DOA) for uniform rectangular array (URA) is presented in this letter. The comprehensive utilization of controllability and observability matrices and automatic pairing technique are considered in this method by using the single snapshot. Therefore, the DOAs of elevation angle and azimuth angle can pair automatically and acquire better estimation performance compared with 2D matrix pencil method or unitary matrix pencil method. In addition, the proposed method can handle correlated signals directly without preprocessing. Simulation is conducted to verify the effectiveness of the proposed method.
      PubDate: Thu, 02 Nov 2017 06:40:12 +000
  • Electromagnetic Scattering by Multiple Columns Partially Buried in a
           Ground Plane

    • Abstract: Wideband electromagnetic scattering from multiple objects partially buried beneath rough earth soil surfaces is an important topic during recent years due to its extensive applications in several fields, such as ground remote sensing, ground penetrating radar applications, and target identification. Due to the advantages of finite-difference time-domain (FDTD) method in calculating the wideband electromagnetic scattering from rough surface in the presence of multiple objects, the FDTD method under ultrawideband (UWB) Gaussian pulse wave incidence is utilized in the present study for analyzing the frequency response of rough soil surfaces with periodically distributed multiple rectangular cross-section columns buried partially. In this paper, the dielectric property of the actual land surface is expressed using the four-component model, and the actual rough land surface is simulated utilizing Monte Carlo method with exponential correlation function. The emphasis of the present study is on analyzing the wideband response signatures of composite backscattering coefficient varying with frequency on the basis of extensive numerical simulations, in particular for calculating and discussing in detail the influence of the root-mean-square height and the correlation length of rough soil surface, soil moisture, the length and the width of the rectangular cross-section column, separation distance, burial depth, and tilt angle on the composite backscattering coefficient.
      PubDate: Wed, 01 Nov 2017 07:21:08 +000
  • Application of a Sparsity Pattern and Region Clustering for Near Field
           Sparse Approximate Inverse Preconditioners in Method of Moments

    • Abstract: This document presents a technique for the generation of Sparse Inverse Preconditioners based on the near field coupling matrices of Method of Moments simulations where the geometry has been partitioned in terms of regions. A distance parameter is used to determine the sparsity pattern of the preconditioner. The rows of the preconditioner are computed in groups at a time, according to the number of unknowns contained in each region of the geometry. Two filtering thresholds allow considering only the coupling terms with a significant weight for a faster generation of the preconditioner and storing only the most significant preconditioner coefficients in order to decrease the memory required. The generation of the preconditioner involves the computation of as many independent linear least square problems as the number of regions in which the geometry is partitioned, resulting in very good scalability properties regarding its parallelization.
      PubDate: Tue, 31 Oct 2017 08:07:16 +000
  • Electromagnetic Scattering of Electrically Large Ship above Sea Surface
           with SBR-SDFM Method

    • Abstract: Hybrid scheme combining shooting and bouncing ray with semi-deterministic facet model is proposed to analyze composite scattering from ship-ocean scene in this study. This model can deal with complex electromagnetic interaction between ship and sea surface. Thus, scattering properties of composite ship-ocean scenes with influence of various parameters (such as incident angle and wind speed) can be studied and analyzed efficiently. Studying such properties is of significance for target detection and high-resolution radar imaging in sea environments. Accuracy and performance of this method are validated and evaluated by comparing with multilevel fast multipole method of FEKO for electrically small objects. All simulation results indicate that the proposed method is suitable for providing preliminary radar cross section prediction of electrically large composite model.
      PubDate: Thu, 26 Oct 2017 00:00:00 +000
  • Non-Foster Matching Circuit Design via Tunable Inductor for VLF Receive
           Loop Antennas

    • Abstract: This paper presents a non-Foster matching circuit (NFC) for very low frequency (VLF) receive loop antennas. A 1 1 m VLF receive loop antenna was designed with a CMOS switch-based tunable inductor built into the NFC. The NFC can be applied to different VLF loop antennas by adjusting the number and inductance of the cells in the tunable inductor. A loop antenna was matched to the designed NFC with −10 dB fractional bandwidth, marking a 383% improvement as well as enhanced transducer gain () compared to most bands in passive matching (over 15–30 kHz). The noise and received signal-to-noise ratio (SNR) of the matching network were assessed to find that, with a low noise floor level (4 dB) receiver, the SNR of the passive loaded antenna performs better than the non-Foster loaded antenna in VLF.
      PubDate: Tue, 24 Oct 2017 00:00:00 +000
  • Research on Spatial Channel Model for Vehicle-to-Vehicle Communication
           Channel in Roadside Scattering Environment

    • Abstract: In this paper, an extension of spatial channel model (SCM) for vehicle-to-vehicle (V2V) communication channel in roadside scattering environment is investigated for the first time theoretically and by simulations. Subsequently, to efficiently describe the roadside scattering environment and reflect the nonstationary properties of V2V channels, the proposed SCM V2V model divides the scattering objects into three categories of clusters according to the location of effective scatterers by introducing critical distance. We derive general expressions for the most important statistical properties of V2V channels, such as channel impulse response, power spectral density, angular power density, autocorrelation function, and Doppler spread of the proposed model. The impact of vehicle speed, traffic density, and angle of departure, angle of arrival, and other statistical performances on the V2V channel model is thoroughly discussed. Numerical simulation results are presented to validate the accuracy and effectiveness of the proposed model.
      PubDate: Sun, 22 Oct 2017 00:00:00 +000
  • A Compact Triple-Band Negative Permittivity Metamaterial for C, X-Band

    • Abstract: We report a new design of triple-band electric metamaterial resonator (TBEMR) based on integration of open delta loops within square ring resonator. This metamaterial resonator has three distinct -negative regions (ENG) over C, X frequency bands. The transmission and reflection response of the proposed subwavelength resonator is analyzed using full-wave electromagnetic solver Ansys HFSS to demonstrate the presence of electrical resonances within frequencies 4–12 GHz. Effective medium parameters permittivity and permeability are extracted from simulated complex scattering parameters to verify existence of ENG regions. The investigations are also carried out regarding dependence of resonant frequencies on design parameters of the TBEMR unit cell. The effective medium ratio for proposed subwavelength resonator is compared with various other metamaterial resonators to indicate its compact nature.
      PubDate: Wed, 18 Oct 2017 09:08:45 +000
  • A Design of Vertical Polarized Conformal Antenna and Its Array Based on
           UAV Structure

    • Abstract: The designs of conformal antenna and its array usually need to combine with different carrier structures. As for cone or cylindrical carrier, through using of invasive weed optimization (IWO), the conformal array should be the optimized design as the antenna installation space requirements of cylindrical carrier; through adopting the antenna unit miniaturization method, it designs out a conformal antenna and makes it easier to be installed and the omnidirectional circular polarized beam is also realized. As for unmanned aircraft carrier, it designs out the low profile of conformal vertical polarization antenna unit; through using the electric field integral equation (EFIE) and electric/magnetic current combined-field integral equation (JMCFIE) and multilevel fast multipole algorithm (MLFMA), it analyzes the two different characteristics of unmanned aircraft carrier on the influence of antenna performance. The results obtained through experiments and JMCFIE analysis are in good agreement; according to unmanned aircraft carrier, it also designed out the antenna in X/K-band spectrum; through IWO, the antenna array is optimized; the test results show that the array scanning angle can reach the corresponding beam direction.
      PubDate: Tue, 17 Oct 2017 00:00:00 +000
  • Scattering of Electric Field from Leaky Coaxial Cable in Confined Area

    • Abstract: The new radiation model for the electric field scattering of single leaky coaxial cable (LCX) being a transmitting antenna in the rectangular blind zone at 1.8 GHz is reported. The effect of varying the receiving antenna distance from the LCX on the fluctuation of radiated field using Ray-Tracing Method is examined. The line of sight and reflected paths between the LCX and receiving antenna for both horizontal and vertical polarizations are considered. Furthermore, it is inferred that the selection of appropriate period of slots and distance of the receiver reduce the fluctuations of electric field. The theory and procedures used in this paper can be extrapolated in different slot patterns of the LCX and zones which have many valuable applications for mobile communication in underground mines, tunnels, and railways.
      PubDate: Mon, 16 Oct 2017 00:00:00 +000
  • Recent Advances in RF Propagation Modeling for 5G Systems

    • PubDate: Sun, 15 Oct 2017 00:00:00 +000
  • Transmission Control of Electromagnetic Waves by Using Quarter-Wave Plate
           and Half-Wave Plate All-Dielectric Metasurfaces Based on Elliptic
           Dielectric Resonators

    • Abstract: We present the design of all-dielectric Quarter-Wave Plate (QWP) and Half-Wave Plate (HWP) metasurfaces based on elliptic dielectric resonators (EDRs) for the transmission control of electromagnetic waves over the frequency band 20–30 GHz. First, an extensive numerical analysis was realized by studying the effect of the resonators geometry (thickness and ellipticity) on the transmission of both - and -polarized waves. Then, based on the numerical analysis, we have realized and characterized experimentally both QWP and HWP all-dielectric metasurfaces.
      PubDate: Tue, 10 Oct 2017 00:00:00 +000
  • Study on Selfish Node Incentive Mechanism with a Forward Game Node in
           Wireless Sensor Networks

    • Abstract: In a wireless sensor network, some nodes may act selfishly and noncooperatively, such as not forwarding packets, in response to their own limited resources. If most of the nodes in a network exhibit this selfish behavior, the entire network will be paralyzed, and it will not be able to provide normal service. This paper considers implementing the idea of evolutionary game theory into the nodes of wireless sensor networks to effectively improve the reliability and stability of the networks. We present a new model for the selfish node incentive mechanism with a forward game node for wireless sensor networks, and we discuss applications of the replicator dynamics mechanism to analyze evolutionary trends of trust relationships among nodes. We analyzed our approach theoretically and conducted simulations based on the idea of evolutionary game theory. The results of the simulation indicated that a wireless sensor network that uses the incentive mechanism can forward packets well while resisting any slight variations. Thus, the stability and reliability of wireless sensor networks are improved. We conducted numerical experiments, and the results verified our conclusions based on the theoretical analysis.
      PubDate: Sun, 08 Oct 2017 00:00:00 +000
  • DOA Estimation of Noncircular Signals Using Quaternions

    • Abstract: The two-dimensional (2D) direction-of-arrival (DOA) estimation problem for noncircular signals using quaternions is considered in this paper. In the framework of quaternions, we reconstruct the conjugate augmented output vector which reduces the dimension of covariance matrix. Compared with existing methods, the proposed one has two main advantages. Firstly, the estimation accuracy is higher since quaternions have stronger orthogonality. Secondly, the dimension of covariance matrix is reduced by half which decreases the computational complexity. Simulation results are presented verifying the efficacy of the algorithm.
      PubDate: Sun, 08 Oct 2017 00:00:00 +000
  • Adaptive Antenna Null Broadening Beamforming against Array Calibration
           Error Based on Adaptive Variable Diagonal Loading

    • Abstract: An approach for null broadening beamforming is proposed based on adaptive variable diagonal loading (VDL) and combined with the covariance matrix taper (CMT) approach, aiming at improving the robustness of adaptive antenna null broadening beamforming when array calibration error exists. Hence, it is named VDL-CMT. In this novel approach, the signal-to-noise ratio in the tapered sample covariance matrix is estimated and the VDL factor can be obtained adaptively. Then, the covariance matrix of the CMT approach is loaded with the obtained VDL factor. According to simulation results, in the case of array calibration error, robustness of the VDL-CMT is significantly improved and its performance is better than that of the existing adaptive antenna null broadening beamforming approaches.
      PubDate: Sun, 08 Oct 2017 00:00:00 +000
  • A Printed LPDA Antenna Fed by a Microstrip Line to Double Sided Parallel
           Strip Line from Backside

    • Abstract: A novel planar printed log-periodic dipole array (LPDA) antenna fed by tapered microstrip line (MSL) to double sided parallel strip line (DSPSL) is proposed in this paper. The proposed antenna adopts MSL feeding approach from backside. Using this feeding technique makes the printed LPDA antenna easier to be integrated into radio frequency (RF) circuits. In this paper, four layers are used to construct the antenna. The four layers of the printed LPDA antenna are printed on three thin dielectric substrates which are integrated together. To validate this approach, a printed LPDA antenna is simulated and fabricated for operating in the S and C bands (2.5–6 GHz). The antenna showed a good result over the whole frequency range with 2 : 1 VSWR, an average gain of 6.5 dB, and stable radiation patterns. The measured results are in very good agreement with simulations.
      PubDate: Sun, 08 Oct 2017 00:00:00 +000
  • Calculation Algorithm for Diffraction Losses of Multiple Obstacles Based
           on Epstein–Peterson Approach

    • Abstract: Applying propagation models with good accuracy is an essential issue for increasing the capacity and improving the coverage of cellular communication systems. This work presents an algorithm to calculate total diffraction losses for multiple obstacles objects using Epstein–Peterson approach. The proposed algorithmic procedure to model the diffracting can be integrated with other propagation mechanisms in ray-tracing for the prediction of received signal level in non-line-of-sight environments. This algorithm can be interpreted into software application to scan large areas with a reasonable simulation time.
      PubDate: Tue, 03 Oct 2017 00:00:00 +000
  • A Novel Scheme with FG-FFT for Analysis of Electromagnetic Scattering from
           Large Objects

    • Abstract: The replacement values to the singularity of fitting Green’s function are intensively researched in Fitting Green’s function Fast Fourier Transformation (FG-FFT). As is shown in the research, the accuracy of fitting Green’s function of near element is affected by different replacement values. The experiments show that an appropriate replacement value can improve the accuracy of fitting Green’s function of near element, and it is called the optimal replacement value in this paper. In the case of application of the proposed scheme to FG-FFT, the number of the near correction elements is significantly reduced. Therefore, the optimal replacement scheme can dramatically reduce the memory requirement and computing time in FG-FFT. The experiments show that, compared with traditional random replacement schemes, the optimal replacement scheme can reduce the number of the near correction elements by about 55%60% and greatly improve the computational efficiency of FG-FFT.
      PubDate: Thu, 28 Sep 2017 12:30:59 +000
  • Combination of the Improved Diffraction Nonlocal Boundary Condition and
           Three-Dimensional Wide-Angle Parabolic Equation Decomposition Model for
           Predicting Radio Wave Propagation

    • Abstract: Diffraction nonlocal boundary condition (BC) is one kind of the transparent boundary condition which is used in the finite-difference (FD) parabolic equation (PE). The greatest advantage of the diffraction nonlocal boundary condition is that it can absorb the wave completely by using one layer of grid. However, the speed of computation is low because of the time-consuming spatial convolution integrals. To solve this problem, we introduce the recursive convolution (RC) with vector fitting (VF) method to accelerate the computational speed. Through combining the diffraction nonlocal boundary with RC, we achieve the improved diffraction nonlocal BC. Then we propose a wide-angle three-dimensional parabolic equation (WA-3DPE) decomposition algorithm in which the improved diffraction nonlocal BC is applied and we utilize it to predict the wave propagation problems in the complex environment. Numeric computation and measurement results demonstrate the computational accuracy and speed of the WA-3DPE decomposition model with the improved diffraction nonlocal BC.
      PubDate: Thu, 28 Sep 2017 00:00:00 +000
  • Anisotropic Scattering Characteristics of a Radially Multilayered
           Gyrotropic Sphere

    • Abstract: We present a new closed-form solution to the scattering of a monochromatic plane wave by a radially multilayered gyrotropic sphere using the -matrix method. This approach can be utilized to investigate the interactions of a plane wave and a gyrotropic spherical scatterer of multiple layers with each layer characterized by both permittivity and permeability tensors. Based on the completeness and noncoplanar properties of vector spherical wave functions (VSWFs), analytical expressions of the electromagnetic fields in each gyrotropic layer are first derived. The boundary conditions are then applied on each discontinuous interface to obtain the scattering coefficients. Validations are made by first comparing the radar cross section (RCS) values of a 2-layered gyrotropic sphere with that computed from the full-wave finite element method (FEM) simulation and then reducing the general case to uniaxial case to compare the RCS values with the published results computed by Fourier transform combined with VSWFs method; in both cases good agreements are observed. Several specific cases are fully explored to investigate how the RCS are influenced by the parameters of the multilayered spherical structure. The results show that when both electric and magnetic gyrotropy tensors are considered, the RCS of the multilayered spherical scatterer can be suppressed or enhanced, depending on proper configurations of the material parameters.
      PubDate: Thu, 28 Sep 2017 00:00:00 +000
  • A Compact Frequency Reconfigurable Hybrid DRA for LTE/Wimax Applications

    • Abstract: A compact hybrid antenna structure with frequency reconfiguration capabilities is presented in this article. The proposed design employs a combination of a rectangular DR element and a coupling slot on the structure’s ground plane (GP). The slot shifts the fundamental DRA mode by introducing a slow wave effect and its resonant behavior helps to achieve an omnidirectional pattern at low frequencies. The slot is loaded with a series of PIN diode switches whose ON/OFF combinations alter the effective slot length. Slot loading with PIN diodes results in frequency reconfiguration of the proposed structure with a large tuning range of 76.2% (between 1.73 and 3.86 GHz). A parametric analysis was performed to investigate the effects of slot length, width, and position on the reflection coefficients of the proposed structure. A prototype of the proposed design was fabricated and results were measured. The measured results show a close agreement with the simulated ones. The proposed design is suitable for DCS 1800 MHz, PCS 1900 MHZ, UMTS, LTE 2500–2700 MHz, and Wimax 3.5 GHz.
      PubDate: Mon, 25 Sep 2017 09:43:21 +000
  • Minimized Low-Profile Wideband Antennas Using High Impedance Surface

    • Abstract: This paper proposes minimized low-profile wideband antenna by employing high impedance surface (HIS), for wireless application scenarios at radio frequency, microwave, and even terahertz. To validate this concept with low cost and easy measurement, two prototypes at radio frequency are fabricated and tested. Firstly, antenna with dielectric-substrate reflector is proposed and analyzed and 4 × 6 HIS array is employed to minimize the antenna size to , while maintaining antenna performances such as bandwidth, gain, and directive radiation. Secondly, a substrate-less HIS is proposed to improve the antenna bandwidth from 36% to 52% and also reduces the antenna weight by 72%.
      PubDate: Tue, 19 Sep 2017 00:00:00 +000
  • Assessment Method of Multipath Mitigation Performance for GNSS Antenna
           with Receiver Algorithms

    • Abstract: Multipath is one of the most important sources of positioning error in GNSS. Well-designed antennas can mitigate multipath signals and enhance the performance of GNSS receivers. This paper concentrates on methods to assess multipath mitigation performance for GNSS antennas. We propose a model to describe multipath environment in GNSS ground stations. The model analyzes effects caused by inclined reflective surfaces and multipath mitigating algorithms in receivers. A method to assess multipath mitigation performance is put forward by analyzing pseudorange code phase errors caused by multipath signals after signal processing. Based on the model and method, principles in site selection for GNSS antenna are introduced to minimize effects caused by multipath.
      PubDate: Mon, 18 Sep 2017 00:00:00 +000
  • Metamaterials, Metasurfaces, and Artificial Dielectrics: Theory and
           Applications to the Next-Generation Telecommunication Platforms

    • PubDate: Mon, 11 Sep 2017 00:00:00 +000
  • Robust Centered Element Concentric Circular Antenna Array with Low Side
           Lobe Using Variable Loading and Tapering Windows in the Presence of Array

    • Abstract: This paper presents centered element concentric circular antenna array (CECCAA) using variable diagonal loading (VDL) technique and different filtering windows. The different filtering windows are modified to apply in the CECCAA system. The modified novel technique not only is able to reduce the side lobe level (SLL) but also has the ability to detect and highly attenuate the directional interferences. However, the performance of CECCAA system is degraded in the presence of array imperfections. This performance degradation problem due to array imperfections can be improved by using robust techniques. The proposed technique is also robust against array imperfections and improves the performance. Moreover, the performance of the proposed structure is better than a concentric circular antenna array (CCAA). Several examples are presented to analyze the performance of proposed beamformer by using different tapering windows.
      PubDate: Sun, 10 Sep 2017 00:00:00 +000
  • Millimeter-Wave Single-Layer Dual-Frequency Reflectarray Antenna

    • Abstract: To fulfill the dual-frequency requirements, elements are needed to resonate at two different, independently adjustably frequencies. A low weight, low cost, and easy to fabricate single-layer dual-frequency reflectarray is designed, fabricated, and measured, with gain values of 27 and 29.2 dBi at 20 and 30 GHz, respectively.
      PubDate: Wed, 06 Sep 2017 08:07:40 +000
School of Mathematical and Computer Sciences
Heriot-Watt University
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