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Publisher: Hindawi   (Total: 338 journals)

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Showing 1 - 200 of 338 Journals sorted alphabetically
Abstract and Applied Analysis     Open Access   (Followers: 3, SJR: 0.343, CiteScore: 1)
Active and Passive Electronic Components     Open Access   (Followers: 8, SJR: 0.136, CiteScore: 0)
Advances in Acoustics and Vibration     Open Access   (Followers: 43, SJR: 0.147, CiteScore: 0)
Advances in Aerospace Engineering     Open Access   (Followers: 57)
Advances in Agriculture     Open Access   (Followers: 10)
Advances in Artificial Intelligence     Open Access   (Followers: 17)
Advances in Astronomy     Open Access   (Followers: 41, SJR: 0.257, CiteScore: 1)
Advances in Bioinformatics     Open Access   (Followers: 18, SJR: 0.565, CiteScore: 2)
Advances in Biology     Open Access   (Followers: 11)
Advances in Chemistry     Open Access   (Followers: 28)
Advances in Civil Engineering     Open Access   (Followers: 48, SJR: 0.539, CiteScore: 1)
Advances in Computer Engineering     Open Access   (Followers: 4)
Advances in Condensed Matter Physics     Open Access   (Followers: 11, SJR: 0.315, CiteScore: 1)
Advances in Decision Sciences     Open Access   (Followers: 3, SJR: 0.303, CiteScore: 1)
Advances in Electrical Engineering     Open Access   (Followers: 42)
Advances in Electronics     Open Access   (Followers: 90)
Advances in Emergency Medicine     Open Access   (Followers: 12)
Advances in Endocrinology     Open Access   (Followers: 6)
Advances in Environmental Chemistry     Open Access   (Followers: 8)
Advances in Epidemiology     Open Access   (Followers: 8)
Advances in Fuzzy Systems     Open Access   (Followers: 5, SJR: 0.161, CiteScore: 1)
Advances in Geology     Open Access   (Followers: 19)
Advances in Geriatrics     Open Access   (Followers: 6)
Advances in Hematology     Open Access   (Followers: 13, SJR: 0.661, CiteScore: 2)
Advances in Hepatology     Open Access   (Followers: 2)
Advances in High Energy Physics     Open Access   (Followers: 22, SJR: 0.866, CiteScore: 2)
Advances in Human-Computer Interaction     Open Access   (Followers: 21, SJR: 0.186, CiteScore: 1)
Advances in Materials Science and Engineering     Open Access   (Followers: 31, SJR: 0.315, CiteScore: 1)
Advances in Mathematical Physics     Open Access   (Followers: 7, SJR: 0.218, CiteScore: 1)
Advances in Medicine     Open Access   (Followers: 3)
Advances in Meteorology     Open Access   (Followers: 24, SJR: 0.48, CiteScore: 1)
Advances in Multimedia     Open Access   (Followers: 2, SJR: 0.173, CiteScore: 1)
Advances in Nonlinear Optics     Open Access   (Followers: 6)
Advances in Numerical Analysis     Open Access   (Followers: 7)
Advances in Nursing     Open Access   (Followers: 33)
Advances in Operations Research     Open Access   (Followers: 12, SJR: 0.205, CiteScore: 1)
Advances in Optical Technologies     Open Access   (Followers: 4, SJR: 0.214, CiteScore: 1)
Advances in Optics     Open Access   (Followers: 6)
Advances in OptoElectronics     Open Access   (Followers: 6, SJR: 0.141, CiteScore: 0)
Advances in Orthopedics     Open Access   (Followers: 8, SJR: 0.922, CiteScore: 2)
Advances in Pharmacological Sciences     Open Access   (Followers: 8, SJR: 0.591, CiteScore: 2)
Advances in Physical Chemistry     Open Access   (Followers: 12, SJR: 0.179, CiteScore: 1)
Advances in Polymer Technology     Open Access   (Followers: 15, SJR: 0.299, CiteScore: 1)
Advances in Power Electronics     Open Access   (Followers: 38, SJR: 0.184, CiteScore: 0)
Advances in Preventive Medicine     Open Access   (Followers: 6)
Advances in Public Health     Open Access   (Followers: 25)
Advances in Regenerative Medicine     Open Access   (Followers: 3)
Advances in Software Engineering     Open Access   (Followers: 11)
Advances in Statistics     Open Access   (Followers: 6)
Advances in Toxicology     Open Access   (Followers: 2)
Advances in Tribology     Open Access   (Followers: 14, SJR: 0.265, CiteScore: 1)
Advances in Urology     Open Access   (Followers: 12, SJR: 0.51, CiteScore: 1)
Advances in Virology     Open Access   (Followers: 7, SJR: 0.838, CiteScore: 2)
AIDS Research and Treatment     Open Access   (Followers: 2, SJR: 0.758, CiteScore: 2)
Analytical Cellular Pathology     Open Access   (Followers: 3, SJR: 0.886, CiteScore: 2)
Anatomy Research Intl.     Open Access   (Followers: 3)
Anemia     Open Access   (Followers: 5, SJR: 0.669, CiteScore: 2)
Anesthesiology Research and Practice     Open Access   (Followers: 15, SJR: 0.501, CiteScore: 1)
Applied and Environmental Soil Science     Open Access   (Followers: 18, SJR: 0.451, CiteScore: 1)
Applied Bionics and Biomechanics     Open Access   (Followers: 7, SJR: 0.288, CiteScore: 1)
Applied Computational Intelligence and Soft Computing     Open Access   (Followers: 14)
Archaea     Open Access   (Followers: 3, SJR: 0.852, CiteScore: 2)
Autism Research and Treatment     Open Access   (Followers: 33)
Autoimmune Diseases     Open Access   (Followers: 3, SJR: 0.805, CiteScore: 2)
Behavioural Neurology     Open Access   (Followers: 9, SJR: 0.786, CiteScore: 2)
Biochemistry Research Intl.     Open Access   (Followers: 7, SJR: 0.437, CiteScore: 2)
Bioinorganic Chemistry and Applications     Open Access   (Followers: 11, SJR: 0.419, CiteScore: 2)
BioMed Research Intl.     Open Access   (Followers: 4, SJR: 0.935, CiteScore: 3)
Biotechnology Research Intl.     Open Access   (Followers: 1)
Bone Marrow Research     Open Access   (Followers: 2, SJR: 0.531, CiteScore: 1)
Canadian J. of Gastroenterology & Hepatology     Open Access   (Followers: 6, SJR: 0.867, CiteScore: 1)
Canadian J. of Infectious Diseases and Medical Microbiology     Open Access   (Followers: 6, SJR: 0.548, CiteScore: 1)
Canadian Respiratory J.     Open Access   (Followers: 1, SJR: 0.474, CiteScore: 1)
Cardiology Research and Practice     Open Access   (Followers: 10, SJR: 1.237, CiteScore: 4)
Cardiovascular Therapeutics     Open Access   (Followers: 1, SJR: 1.075, CiteScore: 2)
Case Reports in Anesthesiology     Open Access   (Followers: 11)
Case Reports in Cardiology     Open Access   (Followers: 7, SJR: 0.219, CiteScore: 0)
Case Reports in Critical Care     Open Access   (Followers: 12)
Case Reports in Dentistry     Open Access   (Followers: 7, SJR: 0.229, CiteScore: 0)
Case Reports in Dermatological Medicine     Open Access   (Followers: 2)
Case Reports in Emergency Medicine     Open Access   (Followers: 15)
Case Reports in Endocrinology     Open Access   (Followers: 2, SJR: 0.209, CiteScore: 1)
Case Reports in Gastrointestinal Medicine     Open Access   (Followers: 2)
Case Reports in Genetics     Open Access   (Followers: 2)
Case Reports in Hematology     Open Access   (Followers: 8)
Case Reports in Hepatology     Open Access   (Followers: 1)
Case Reports in Immunology     Open Access   (Followers: 5)
Case Reports in Infectious Diseases     Open Access   (Followers: 5)
Case Reports in Medicine     Open Access   (Followers: 2)
Case Reports in Nephrology     Open Access   (Followers: 5)
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, SJR: 0.204, CiteScore: 1)
Case Reports in Ophthalmological Medicine     Open Access   (Followers: 3)
Case Reports in Orthopedics     Open Access   (Followers: 6)
Case Reports in Otolaryngology     Open Access   (Followers: 7)
Case Reports in Pathology     Open Access   (Followers: 7)
Case Reports in Pediatrics     Open Access   (Followers: 7)
Case Reports in Psychiatry     Open Access   (Followers: 16)
Case Reports in Pulmonology     Open Access   (Followers: 3)
Case Reports in Radiology     Open Access   (Followers: 11)
Case Reports in Rheumatology     Open Access   (Followers: 8)
Case Reports in Surgery     Open Access   (Followers: 12)
Case Reports in Transplantation     Open Access  
Case Reports in Urology     Open Access   (Followers: 11)
Case Reports in Vascular Medicine     Open Access  
Case Reports in Veterinary Medicine     Open Access   (Followers: 5)
Child Development Research     Open Access   (Followers: 18, SJR: 0.144, CiteScore: 0)
Chinese J. of Engineering     Open Access   (Followers: 2, SJR: 0.114, CiteScore: 0)
Chinese J. of Mathematics     Open Access  
Chromatography Research Intl.     Open Access   (Followers: 5)
Complexity     Hybrid Journal   (Followers: 6, SJR: 0.531, CiteScore: 2)
Computational and Mathematical Methods in Medicine     Open Access   (Followers: 2, SJR: 0.403, CiteScore: 1)
Computational Intelligence and Neuroscience     Open Access   (Followers: 13, SJR: 0.326, CiteScore: 1)
Contrast Media & Molecular Imaging     Open Access   (Followers: 3, SJR: 0.842, CiteScore: 3)
Critical Care Research and Practice     Open Access   (Followers: 12, SJR: 0.499, CiteScore: 1)
Current Gerontology and Geriatrics Research     Open Access   (Followers: 9, SJR: 0.512, CiteScore: 2)
Depression Research and Treatment     Open Access   (Followers: 15, SJR: 0.816, CiteScore: 2)
Dermatology Research and Practice     Open Access   (Followers: 3, SJR: 0.806, CiteScore: 2)
Diagnostic and Therapeutic Endoscopy     Open Access   (SJR: 0.201, CiteScore: 1)
Discrete Dynamics in Nature and Society     Open Access   (Followers: 5, SJR: 0.279, CiteScore: 1)
Disease Markers     Open Access   (Followers: 1, SJR: 0.9, CiteScore: 2)
Economics Research Intl.     Open Access   (Followers: 1)
Education Research Intl.     Open Access   (Followers: 19)
Emergency Medicine Intl.     Open Access   (Followers: 9, SJR: 0.298, CiteScore: 1)
Enzyme Research     Open Access   (Followers: 5, SJR: 0.653, CiteScore: 3)
Evidence-based Complementary and Alternative Medicine     Open Access   (Followers: 23, SJR: 0.683, CiteScore: 2)
Game Theory     Open Access   (Followers: 1)
Gastroenterology Research and Practice     Open Access   (Followers: 2, SJR: 0.768, CiteScore: 2)
Genetics Research Intl.     Open Access   (Followers: 1, SJR: 0.61, CiteScore: 2)
Geofluids     Open Access   (Followers: 5, SJR: 0.952, CiteScore: 2)
Hepatitis Research and Treatment     Open Access   (Followers: 6, SJR: 0.389, CiteScore: 2)
Heteroatom Chemistry     Open Access   (Followers: 3, SJR: 0.333, CiteScore: 1)
HPB Surgery     Open Access   (Followers: 7, SJR: 0.824, CiteScore: 2)
Infectious Diseases in Obstetrics and Gynecology     Open Access   (Followers: 5, SJR: 1.27, CiteScore: 2)
Interdisciplinary Perspectives on Infectious Diseases     Open Access   (Followers: 1, SJR: 0.627, CiteScore: 2)
Intl. J. of Aerospace Engineering     Open Access   (Followers: 75, SJR: 0.232, CiteScore: 1)
Intl. J. of Agronomy     Open Access   (Followers: 6, SJR: 0.311, CiteScore: 1)
Intl. J. of Alzheimer's Disease     Open Access   (Followers: 11, SJR: 0.787, CiteScore: 3)
Intl. J. of Analytical Chemistry     Open Access   (Followers: 22, SJR: 0.285, CiteScore: 1)
Intl. J. of Antennas and Propagation     Open Access   (Followers: 11, SJR: 0.233, CiteScore: 1)
Intl. J. of Atmospheric Sciences     Open Access   (Followers: 22)
Intl. J. of Biodiversity     Open Access   (Followers: 3)
Intl. J. of Biomaterials     Open Access   (Followers: 5, SJR: 0.511, CiteScore: 2)
Intl. J. of Biomedical Imaging     Open Access   (Followers: 3, SJR: 0.501, CiteScore: 2)
Intl. J. of Breast Cancer     Open Access   (Followers: 14, SJR: 1.025, CiteScore: 2)
Intl. J. of Cell Biology     Open Access   (Followers: 4, SJR: 1.887, CiteScore: 4)
Intl. J. of Chemical Engineering     Open Access   (Followers: 9, SJR: 0.327, CiteScore: 1)
Intl. J. of Chronic Diseases     Open Access   (Followers: 1)
Intl. J. of Combinatorics     Open Access   (Followers: 1)
Intl. J. of Computer Games Technology     Open Access   (Followers: 10, SJR: 0.287, CiteScore: 2)
Intl. J. of Corrosion     Open Access   (Followers: 10, SJR: 0.194, CiteScore: 1)
Intl. J. of Dentistry     Open Access   (Followers: 8, SJR: 0.649, CiteScore: 2)
Intl. J. of Differential Equations     Open Access   (Followers: 8, SJR: 0.191, CiteScore: 0)
Intl. J. of Digital Multimedia Broadcasting     Open Access   (Followers: 5, SJR: 0.296, CiteScore: 2)
Intl. J. of Electrochemistry     Open Access   (Followers: 8)
Intl. J. of Endocrinology     Open Access   (Followers: 4, SJR: 1.012, CiteScore: 3)
Intl. J. of Engineering Mathematics     Open Access   (Followers: 7)
Intl. J. of Food Science     Open Access   (Followers: 5, SJR: 0.44, CiteScore: 2)
Intl. J. of Forestry Research     Open Access   (Followers: 3, SJR: 0.373, CiteScore: 1)
Intl. J. of Genomics     Open Access   (Followers: 2, SJR: 0.868, CiteScore: 3)
Intl. J. of Geophysics     Open Access   (Followers: 5, SJR: 0.182, CiteScore: 1)
Intl. J. of Hepatology     Open Access   (Followers: 5, SJR: 0.874, CiteScore: 2)
Intl. J. of Hypertension     Open Access   (Followers: 8, SJR: 0.578, CiteScore: 1)
Intl. J. of Inflammation     Open Access   (SJR: 1.264, CiteScore: 3)
Intl. J. of Inorganic Chemistry     Open Access   (Followers: 3)
Intl. J. of Manufacturing Engineering     Open Access   (Followers: 2)
Intl. J. of Mathematics and Mathematical Sciences     Open Access   (Followers: 3, SJR: 0.177, CiteScore: 0)
Intl. J. of Medicinal Chemistry     Open Access   (Followers: 6, SJR: 0.31, CiteScore: 1)
Intl. J. of Metals     Open Access   (Followers: 7)
Intl. J. of Microbiology     Open Access   (Followers: 8, SJR: 0.662, CiteScore: 2)
Intl. J. of Microwave Science and Technology     Open Access   (Followers: 3, SJR: 0.136, CiteScore: 1)
Intl. J. of Navigation and Observation     Open Access   (Followers: 20, SJR: 0.267, CiteScore: 2)
Intl. J. of Nephrology     Open Access   (Followers: 1, SJR: 0.697, CiteScore: 1)
Intl. J. of Oceanography     Open Access   (Followers: 8)
Intl. J. of Optics     Open Access   (Followers: 8, SJR: 0.231, CiteScore: 1)
Intl. J. of Otolaryngology     Open Access   (Followers: 3)
Intl. J. of Partial Differential Equations     Open Access   (Followers: 2)
Intl. J. of Pediatrics     Open Access   (Followers: 6)
Intl. J. of Peptides     Open Access   (Followers: 2, SJR: 0.46, CiteScore: 1)
Intl. J. of Photoenergy     Open Access   (Followers: 3, SJR: 0.341, CiteScore: 1)
Intl. J. of Plant Genomics     Open Access   (Followers: 4, SJR: 0.583, CiteScore: 1)
Intl. J. of Polymer Science     Open Access   (Followers: 28, SJR: 0.298, CiteScore: 1)
Intl. J. of Population Research     Open Access   (Followers: 4)
Intl. J. of Quality, Statistics, and Reliability     Open Access   (Followers: 17)
Intl. J. of Reconfigurable Computing     Open Access   (SJR: 0.123, CiteScore: 1)
Intl. J. of Reproductive Medicine     Open Access   (Followers: 5)
Intl. J. of Rheumatology     Open Access   (Followers: 4, SJR: 0.645, CiteScore: 2)
Intl. J. of Rotating Machinery     Open Access   (Followers: 2, SJR: 0.193, CiteScore: 1)
Intl. J. of Spectroscopy     Open Access   (Followers: 8)
Intl. J. of Stochastic Analysis     Open Access   (Followers: 3, SJR: 0.279, CiteScore: 1)
Intl. J. of Surgical Oncology     Open Access   (Followers: 1, SJR: 0.573, CiteScore: 2)
Intl. J. of Telemedicine and Applications     Open Access   (Followers: 5, SJR: 0.403, CiteScore: 2)
Intl. J. of Vascular Medicine     Open Access   (SJR: 0.782, CiteScore: 2)
Intl. J. of Zoology     Open Access   (Followers: 2, SJR: 0.209, CiteScore: 1)
Intl. Scholarly Research Notices     Open Access   (Followers: 216)
ISRN Astronomy and Astrophysics     Open Access   (Followers: 7)
J. of Addiction     Open Access   (Followers: 14)
J. of Advanced Transportation     Hybrid Journal   (Followers: 13, SJR: 0.581, CiteScore: 1)
J. of Aerodynamics     Open Access   (Followers: 14)

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Similar Journals
Journal Cover
International Journal of Antennas and Propagation
Journal Prestige (SJR): 0.233
Citation Impact (citeScore): 1
Number of Followers: 11  

  This is an Open Access Journal Open Access journal
ISSN (Print) 1687-5869 - ISSN (Online) 1687-5877
Published by Hindawi Homepage  [338 journals]
  • DOA Estimation of Two-Dimensional Coherently Distributed Sources Based on
           Spatial Smoothing of Uniform Rectangular Arrays

    • Abstract: Aiming at the direction-of-arrival (DOA) estimation of two-dimensional (2D) coherently distributed (CD) sources which are coherent with each other, we explore the propagator method based on spatial smoothing of a uniform rectangular array (URA). The rotational invariance relationships with respect to the nominal azimuth and nominal elevation are obtained under the small angular spreads assumption. A propagator operator is constructed through spatial smoothing of sample covariance matrices firstly. Then, combination of propagator and identical matrix is divided according to rotational operators, and the nominal angles can be obtained through eigendecomposition lastly. Realizing angle matching automatically, the proposed method can estimate multiple DOAs of 2D coherent CD sources without spectral peak searching and prior knowledge of deterministic angular signal distribution function. Simulations are conducted to verify the effectiveness of the proposed method.
      PubDate: Mon, 07 Oct 2019 03:05:00 +000
       
  • RFID Double-Loop Tags with Novel Meandering Lines Design for Health
           Monitoring Application

    • Abstract: In this paper, we propose a design of two compact and miniaturized RFID epidermal tags in the UHF band for health monitoring applications. The two conceptions of meandered double-loop antennas with T-match configuration, namely, a double-loop antenna with meandered line in the horizontal direction and a double-loop antenna with meandered lines in two directions, are placed at very close distance from the human body. The proposed tags are composed of bio-silicone substrate, to protect the human skin from the electromagnetic waves, and a copper conductor loaded by T-match configuration, to suit the complex impedance of the antenna to that of the chip. We have performed numerical simulations of these conceptions of two tags using the HFSS and CST solvers. Our results show two optimal sizes with a high communication performance, good matching features, and a large read range. We placed afterwards these two optimized tags in an elliptical environment to test their flexibility and examine their performance on different parts of the human body.
      PubDate: Tue, 01 Oct 2019 13:05:01 +000
       
  • Low-Cost Air Gap Metasurface Structure for High Absorption Efficiency
           Energy Harvesting

    • Abstract: This manuscript deals with the design of a metamaterial-based surface structure for high efficiency wireless power harvesting or collection. Differently from the previously presented structures which require the use of thicker and low-loss (and for this reason high cost) dielectric substrates, the presented work employs a dual-layer structure with a thin low-loss material and an air gap; they allow for the design of very high absorption efficiency metamaterial-based surfaces, with noticeably reduced costs. Furthermore, the air gap thickness can be used as a new degree-of-freedom (more easily adjustable than the thickness of a single-layer structure) for the optimization of other design requirements such as bandwidth or structure sizes. In comparison with other existing designs, the proposed metasurface shows a comparable absorption efficiency of 84.4% but with a larger power collection surface and lower costs.
      PubDate: Thu, 26 Sep 2019 11:05:00 +000
       
  • An Efficient Laguerre-Based FDTD Iterative Algorithm in 3D Cylindrical
           Coordinate System

    • Abstract: Here an efficient Laguerre-based finite-difference time-domain iterative algorithm is proposed. Different from the previously developed iterative procedure used in the efficient FDTD algorithm, a new perturbation term combined with the Gauss–Seidel iterative procedure is introduced to form the new Laguerre-based FDTD algorithm in the 3D cylindrical coordinate system. Such a treatment scheme can reduce the splitting error to a low level and obtain a good convergence; in other words, it can improve the efficiency and accuracy than other algorithms. To verify the performance of the proposed algorithm, two scattering numerical examples are given. The computation results show that the proposed algorithm can be better than the ADI-FDTD algorithm in terms of efficiency and accuracy. Meanwhile, the proposed algorithm is extremely useful for the problems with fine structures in the 3D cylindrical coordinate system.
      PubDate: Wed, 25 Sep 2019 07:05:09 +000
       
  • A Central Symmetrical and Low-Profile Omnidirectional Circularly Polarized
           Antenna

    • Abstract: In this paper, a compact circularly polarized (CP) antenna with omnidirectional radiation is presented, which has a central symmetric configuration (CSC) and planar structure. It consists of three identical end-fire CP antenna units. Based on the combination of two parallel complementary current sources, each unit cell can be realized by a scalloped cavity and a couple of curved strip lines. Due to a single-layer circular structure with low profile, this configuration can be excited by a coaxial probe in the centre of the whole frame simultaneously. In addition, this prototype was miniaturized with a diameter of 32 mm (0.266, the wavelength of the centre frequency in free space is represented by) and a height of 1.5 mm (0.012). Centre resonance frequency 2.492 GHz is selected, resulting in an omnidirectional radiation and impedance bandwidth (VSWR ≤ 2) of 25 MHz (2481–2506 MHz).
      PubDate: Tue, 24 Sep 2019 04:05:02 +000
       
  • Antenna Element Index Modulation for Frequency Diverse Array

    • Abstract: In this paper, we propose a new architecture and provide performance analysis for frequency diverse array (FDA) Radar combined with the index modulation (IM) techniques. Here, the IM concept is applied upon frequency offsets in an FDA. Information is transmitted by a dynamically selected subset of antenna element indices applying predefined carrier frequency offsets, which generate different radiation patterns. It is shown that this enables the capability for simultaneous wireless communication and FDA Radar that has the range-angle coupling issue resolved.
      PubDate: Sun, 22 Sep 2019 00:06:00 +000
       
  • Polarization and DOA Estimation Based on Dual-Polarized Conformal Array

    • Abstract: A dual-polarized multiple signal classification (DP-MUSIC) algorithm is presented to estimate the arrival directions and polarizations for a dual-polarized conformal array. Each polarization signal is decomposed into two orthogonal polarization components, which are considered to be a pair of coherent signals coming from the same direction but different polarization. The polarization parameters are modeled as the equivalent coherence coefficients of the orthogonal polarization components. Then, the method of decoherence can be used to decouple the information of polarization states and signal angles. After that, the direction of arrival (DOA) and polarization parameters can be estimated by the DP-MUSIC algorithm. Moreover, the angles of incident direction are re-estimated, which greatly improves the accuracy of DOA estimation. The Cramer–Rao bound (CRB) is derived and the effectiveness of the proposed algorithm is verified by Monte Carlo simulations.
      PubDate: Wed, 18 Sep 2019 14:15:00 +000
       
  • Outdoor-to-Indoor Channel Measurement and Coverage Analysis for 5G Typical
           Spectrums

    • Abstract: The fifth-generation (5G) mobile communications system will adopt the millimeter wave (mmWave) band for outdoor-to-indoor (O2I) coverage to achieve ultrahigh data rate. However, it is a challenging task because of the large path loss and almost total blocking by building walls. In this work, we performed extensive measurements on the O2I propagation at 3.5, 4.9, and 28 GHz simultaneously by using a multiband channel sounder. We captured the path loss distribution and angular power arrival profiles. We also measured the penetration loss at 28 GHz through different kinds of glass windows. The widely adopted ordinary glass windows introduce the penetration loss of 3 to 12 dB that is acceptable and makes mmWave O2I coverage feasible. But the low-emissivity (low-E) windows that will be more popular in the future introduce 10 dB higher loss. The measurement results in this work can help analyse and anticipate the O2I coverage by mmWave, which is important for the design and deployment of the 5G network.
      PubDate: Mon, 16 Sep 2019 07:05:01 +000
       
  • DOA Estimation Performance Analysis and Verification of Dual
           Crossed-Loop/Monopole Antenna Array

    • Abstract: The compact high-frequency surface wave radar using a crossed-loop/monopole (CLM) antenna as the receiving sensor has been widely used in ocean remote sensing and target monitoring. However, the direction of arrival (DOA) estimation accuracy of a single CLM antenna is the dominant factor that restricts the target monitoring performance of the compact HF radar. Besides, the single CLM antenna can estimate two signals simultaneously at most, but its effectiveness is challenged by the pattern distortion and the existence of coherent sources, which limits the application range of the compact HF radar. In this study, a compact array combining two CLM antennas is proposed to improve the DOA estimation accuracy and solve the multisource DOA estimation problem. The estimation error and multisource DOA estimation performance of a dual CLM antenna array are analyzed by formula derivation and simulation. Furthermore, the field experiment results are given to demonstrate the performance improvement of the dual CLM antenna array.
      PubDate: Mon, 16 Sep 2019 06:05:00 +000
       
  • Continuously Frequency-Tunable Horn Filtennas Based on Dual-Post
           Resonators

    • Abstract: This work reports the concept and development of two mechanically frequency-tunable horn filtennas for microwave and millimeter-waves. Our design approach relies on the integration of a horn antenna with a mechanically tunable filter based on dual-post resonators. The proposed filtennas have been manufactured and experimentally characterized, by means of reflection coefficient, radiation pattern, and gain. Measurements demonstrate that both filtennas have a tuning ratio of approximately 1.37 with continuous adjustment. The first prototype operates from 2.56 to 3.50 GHz, whereas in the second one the bandwidth is from 17.4 to 24.0 GHz. In addition, the higher-frequency filtenna has been implemented in a 5.0-meter-reach indoor environment, using a 16-QAM signal at 24 GHz. The best configuration in terms of performance resulted in a root mean square error vector magnitude (EVMRMS) and antenna radiation efficiency of 3.69% and 97.0%, respectively.
      PubDate: Sun, 15 Sep 2019 00:05:29 +000
       
  • Optimal Design of Multiband Microstrip Antennas by Self-Renewing Fitness
           Estimation of Particle Swarm Optimization Algorithm

    • Abstract: In order to reduce the time of designing microstrip antenna, this paper proposes a self-renewing fitness estimation of particle swarm optimization algorithm (SFEPSO) to improve the design efficiency. Firstly, a fitness predictive model of the particles is constructed according to the evolution formula of particle swarm optimization (PSO). From the third generation of the algorithm, the fitness of particles is given by the prediction model instead of the full-wave electromagnetic simulation. Aiming to keep the right direction of evolution, the prediction model will be proofed every N generation during the optimization process. If the prediction model accuracy is lower than the threshold, it will be updated and then continue iterating until the particles satisfy the demands. Compared with the traditional optimization method, this method greatly reduces the evaluation time and improves the design efficiency. The method is validated by the optimized design of E-type dual-frequency microstrip antenna and WLAN/WiMAX multiband antenna. The optimized results show that the purpose of rapid optimization can be achieved while ensuring the design accuracy.
      PubDate: Thu, 12 Sep 2019 10:05:10 +000
       
  • Vehicular Channel in Urban Environments at 23 GHz for Flexible Access
           Common Spectrum Application

    • Abstract: With the development of the vehicular network, new radio technologies have been in the spotlight for maximizing the utilization of the limited radio spectrum resource while accommodating the increasing amount of services and applications in the wireless mobile networks. New spectrum policies based on dynamic spectrum access technology such as flexible access common spectrum (FACS) have been adopted by the Korea Communications Commission (KCC). 23 GHz bands have been allocated to FACS bands by the KCC, which is expected extensively for vehicular communications. The comprehensive knowledge on the radio channel is essential to effectively support the design, simulation, and development of such radio technologies. In this paper, the characteristics of 23 GHz vehicle-to-infrastructure (V2I) channels are simulated and extracted for the urban environment in Seoul. The path loss, shadow factor, Ricean K-factor, root-mean-square (RMS) delay spread, and angular spreads are characterized from the calibrated ray-tracing simulation results, and it can help researchers have a better understanding of the propagation channel for designing vehicular radio technologies and a communication system in a similar environment.
      PubDate: Thu, 12 Sep 2019 05:05:03 +000
       
  • Small-Size Wide-Band Low-Profile “Pixel Antenna”: Comparison of
           Theoretical and Experimental Results in L Band

    • Abstract: This paper presents a small (≈λ/2 × λ/2) low-profile (λ/10) planar antenna built to work on a very large frequency band (≥40%) for applications in Telecom, Radar, IoT, etc. This antenna is called a “Pixel Antenna” because it was first used as a pixel in an agile beam radiating surface. In this paper, the pixel antenna is used alone to design multiband or wide-band antennas keeping the same radiation pattern and polarization throughout the band. The working principle used to design the Pixel Antenna is deduced from the well-known EBG (electromagnetic band gap) antenna in its low-profile version which already has a bandwidth close to ≈20%. The aim of this present work is to double this bandwidth by simultaneously feeding two modes of the original EBG material. The theoretical and experimental results are compared for an L band application, exhibiting bandwidth from 1 GHz to 1.52 GHz (41%). In addition, good radiation patterns of pixel antenna stay constant over the entire useful band without any degradation of the antenna performance. This proposed antenna design can be used to obtain wide bandwidth for any chosen frequency band (S band, X band, C band, etc.) using frequency scaling.
      PubDate: Tue, 10 Sep 2019 08:05:07 +000
       
  • A Compact Wideband Printed Antenna for 4G/5G/WLAN Wireless Applications

    • Abstract: A compact wideband printed antenna with deca-band 4G/5G/WLAN for mobile phone devices is proposed in this paper. The complete structure is composed of a monopole antenna and a coupling strip, occupying a small C-shape PCB area of 27 × 10.8 mm2. This antenna, which is printed on FR4 substrate with 0.8 mm thickness and fed by a coaxial cable, can provide three wide operating bandwidths that cover 685–1012 MHz, 1596–2837 MHz, and 3288–3613 MHz for 4G/5G/WLAN communication systems. The gains and total radiation efficiencies of the antenna in the low, middle, and high bands are 1.4 dBi–2.5 dBi and 38%–47%, respectively. Besides, the measured results are in good agreement with the simulated results. Further experiments demonstrate that the proposed antenna exhibits a good performance for mobile phones.
      PubDate: Tue, 10 Sep 2019 08:05:05 +000
       
  • Probe Selection and Power Weighting in Multiprobe OTA Testing: A Neural
           Network-Based Approach

    • Abstract: Over-the-air (OTA) radiated testing is an efficient solution to evaluate the performance of multiple-input multiple-output (MIMO) capable devices, which can emulate realistic multipath channel conditions in a controlled manner within lab environment. In a multiprobe anechoic chamber- (MPAC-) based OTA setup, determining the most appropriate probe locations and their power weights is critical to improve the accuracy of channel emulation at reasonable system costs. In this paper, a novel approach based on neural networks (NNs) is proposed to derive suitable angular locations as well as power weights of OTA probe antennas; in particular, by using the regularization technique, active probe locations and their weights can be optimized simultaneously with only one training process of the proposed NN. Simulations demonstrate that compared with the convex optimization-based approach to perform probe selection in the literature, e.g., the well-known multishot algorithm, the proposed NN-based approach can yield similar channel emulation accuracy with significantly reduced computational complexity.
      PubDate: Tue, 10 Sep 2019 02:05:02 +000
       
  • Circularly Polarized Wearable Antenna Based on NinjaFlex-Embedded
           Conductive Fabric

    • Abstract: A circularly polarized (CP) wearable antenna based on the FDM (fused deposition modeling) technology is proposed. Conductive fabric is used to realize conductive parts of the patch antenna on the NinjaFlex substrate. The antenna is encapsulated with additional layers of NinjaFlex. Modified patch ensures the CP character at 2.45 GHz. Bending and washing tests are conducted to check the performance stability, and good agreement between simulated and measured results is observed. The experimental results illustrate that the antenna holds 11% 10 dB S11 bandwidth and around 70 MHz 3 dB axial ratio bandwidth. In addition, surface current analysis is also given to understand the operating mechanism of CP wave.
      PubDate: Sun, 08 Sep 2019 13:30:00 +000
       
  • A New Adaptive System for Suppression of Transient Wind Disturbance in
           Large Antennas

    • Abstract: Under transient wind disturbance, vibration deformation of the large antenna surface profile causes deterioration of pointing performance. This paper presents a new adaptive system to suppress unknown transient wind disturbance. First, to monitor the vibration, based on the acceleration measurement and a low-order flexible model considering equivalent identification of forces, the real-time estimation of the vibration state is obtained in an unbiased minimum-variance way. Next, a novel four-cable-actuator mechanism with a circular slide track is proposed for suppressing the vibration, in which the locations of the cable drivers on the slide track are determined according to the attitude of the antenna, and the expected tension distribution of the cables is found by the vibration state and the optimal gain of the linear quadratic regulator (LQR). In the end, the simulation implementation of a 7.3 m antenna under the transient wind disturbance is used to verify the effectiveness of the proposed method.
      PubDate: Wed, 04 Sep 2019 00:00:00 +000
       
  • Channel Characteristics of High-Speed Railway Station Based on Ray-Tracing
           Simulation at 5G mmWave Band

    • Abstract: In order to satisfy the increasing demand for the higher transmission capacity of “smart station”, millimeter wave (mmWave) technology is expected to play a significant role in the high data rate communication system. Based on the ray-tracing simulation technology, this paper would study wireless channel characteristics of the three-dimensional (3D) model of high-speed railway station at the mmWave band. Key parameters such as path loss exponent, shadow fading factor, delay spread, Rician K-factor, angular spread, power angle spectrum, and spatial correlation are extracted and investigated. These channel characteristics are of value for the selection of antenna arrays and even the design of future 5G communication networks in the railway environment.
      PubDate: Mon, 02 Sep 2019 00:05:37 +000
       
  • Experimental Study of Polarized Radar Scattering from the Tree Canopy at
           the Ka-Band

    • Abstract: In this study, experimental measurements were carried out to estimate the polarized backscattering coefficient at the Ka-band through deciduous and coniferous trees. By utilizing a ground-based scatterometer, the returned signal was obtained in three polarized states at an incident angle ranging from 30 to 80 degrees. The scattering coefficients were estimated from the radar equation for the distributed target under narrow beam approximation. Radiometric calibration was conducted using a metal sphere, and a set of corner reflectors was used as the calibration target to ensure measurement accuracy. Both frequency and angular response of backscattering coefficients with three polarizations were analyzed for the cases of deciduous (banyan) and coniferous (pine) trees. The results indicated that the dynamic range for HV polarization is higher than that of HH and VV polarizations for both banyan and pine trees. Comparatively, the dynamic range for the pine tree is larger than that of the banyan tree.
      PubDate: Thu, 29 Aug 2019 07:05:04 +000
       
  • Triband Compact Printed Antenna for 2.4/3.5/5 GHz WLAN/WiMAX
           Applications

    • Abstract: This research presents a triband compact printed antenna for WLAN and WiMAX applications. The antenna structure consists of a folded open stub, long and short L-shaped strips, and asymmetric trapezoid ground plane. Besides, it is of simple structure and operable in 2.4 GHz and 5 GHz (5.2/5.8 GHz) WLAN and 3.5/5.5 GHz WiMAX bands. The folded open stub and long and short L-shaped strips realize impedance matching at 2.4, 3.5, 5.2, and 5.8 GHz, and the asymmetric trapezoid ground plane fine-tunes impedance matching at 5.2, 5.5, and 5.8 GHz. In addition, the equivalent circuit model consolidated into lumped elements is also presented to explain its impedance matching characteristics. In this study, simulations were carried out, and a prototype antenna was fabricated and experimented. The simulation and experimental results are in good agreement. Specifically, the simulated and experimental radiation patterns are omnidirectional at 2.4, 3.5, and 5.2 GHz and near-omnidirectional at 5.5 and 5.8 GHz. Furthermore, the simulated and measured antenna gains are 1.269–3.074 dBi and 1.10–2.80 dBi, respectively. Essentially, the triband compact printed antenna covers 2.4 GHz and 5 GHz (5.2/5.8 GHz) WLAN and 3.5/5.5 GHz WiMAX frequency bands and thereby is a good candidate for WLAN/WiMAX applications.
      PubDate: Wed, 28 Aug 2019 12:05:06 +000
       
  • A Wideband Differential-Fed Microstrip Patch Antenna Based on Radiation of
           Three Resonant Modes

    • Abstract: A wideband differential-fed microstrip patch antenna based on radiation of three resonant modes of TM12, TM30, and slot is proposed in this paper. Firstly, two symmetrical rectangular slots are cut on the radiating patch where the zero-current position of the TM30 mode excites another resonant slot mode. In addition, the slot’s length is enlarged to decrease the frequency of the slot mode with little effect on that of the TM30 mode. To further expand the impedance bandwidth, the width of patch is reduced to increase the frequency of the TM12 mode, while having little influence on that of the TM30 and slot modes. Moreover, a pair of small rectangular strips is adopted on the top of the feeding probes to achieve a good impedance matching. Finally, based on the arrangements above, a broadband microstrip patch antenna with three in-band minima is realized. The results show that the impedance bandwidth () of the proposed antenna is extended to 35.8% at the profile of 0.067 free-space wavelength. Meanwhile, the proposed antenna maintains a stable radiation pattern in the operating band.
      PubDate: Wed, 28 Aug 2019 07:05:08 +000
       
  • A Miniaturized Periodic Microstrip Leaky Wave Antenna with Shorting Pins

    • Abstract: A miniaturized periodic microstrip leaky wave antenna (MLWA) with shorting pins is proposed in this paper. The suggested antenna consists of a number of stubs that are periodically placed on the side of the transmission line, with the outside edges of the stubs being all integrated with shorting pins. In comparison with the whole-width stubs MLWA, the proposed antenna has an advantage of effective reduction in antenna size for the similar beam-scanning capability. A series of simple and effective equations were obtained to calculate the propagation constant and determine the operating band of the antenna. The consistency of the calculated and measured propagation constant confirms the validity of the parameter equations. As demonstrated by experimental results, the main beam scans electronically and continuously from 145° to 61° in the y-z plane as the operating frequency changes from 5.7 GHz to 11.7 GHz.
      PubDate: Wed, 28 Aug 2019 04:05:01 +000
       
  • Anatomically and Dielectrically Realistic 2.5D 5-Layer Reconfigurable Head
           Phantom for Testing Microwave Stroke Detection and Classification

    • Abstract: This work presents the design and manufacturing of an anatomically and dielectrically realistic layered phantom of the human head that allows the insertion of ischemic and hemorrhagic stroke phantom models. A 2.5D physical phantom was designed using a representative anatomical image of the human head, which was simplified into 5 different layers that mimic the scalp, skull, cerebrospinal fluid, brain, and stroke regions in terms of anatomy and dielectric properties. Apart from the brain phantom, all other layers consist of a mixture of polyurethane rubber, graphite powder, and carbon black powder. The brain phantom is in the liquid form to facilitate the insertion of different stroke models (ischemic or hemorrhagic) with different positions and shapes. Phantoms were designed with dielectric properties valid within the frequency range 0.5–3.0 GHz, which is relevant for microwave stroke detection and classification. Molds for casting individual parts of the phantom were printed in 3D. The presented phantom is suitable for the development and testing of microwave systems and algorithms used in the detection and classification of vascular events relevant to stroke diagnosis.
      PubDate: Sun, 25 Aug 2019 00:05:30 +000
       
  • Circularly Polarized Omnidirectional Antenna with Dipole Core and
           Diagonally Adjoined Parasitic Braces for ISM Band Applications

    • Abstract: This research proposes a circularly polarized (CP) single-fed omnidirectional dipole antenna operable in 2.45 GHz frequency for the industrial, scientific, and medical (ISM) radio band applications. The proposed antenna consisted of bisectional dipole core, a pair of quarter-wave baluns, and four diagonally adjoined parasitic braces. The bisectional dipole core was utilized to improve the antenna gain and realize omnidirectional radiation pattern, and the quarter-wave baluns were to symmetrize the current on the bisectional core. The four parasitic braces collectively generated circular polarization. In the study, simulations were conducted using CST Microwave Studio and a prototype antenna fabricated. To validate, experiments were carried out, and simulation and experimental results compared. The finding revealed good agreement between the simulation and experimental results. Essentially, in addition to achieving an antenna gain of 2.07 dBic, the proposed CP single-fed omnidirectional antenna is suited to ISM frequency band applications.
      PubDate: Wed, 21 Aug 2019 12:05:06 +000
       
  • Analysis of GPR Wave Propagation in Complex Underground Structures Using
           CUDA-Implemented Conformal FDTD Method

    • Abstract: Ground penetrating radar (GPR), as a kind of fast, effective, and nondestructive tool, has been widely applied to nondestructive testing of road quality. The finite-difference time-domain method (FDTD) is the common numerical method studying the GPR wave propagation law in layered structure. However, the numerical accuracy and computational efficiency are not high because of the Courant-Friedrichs-Lewy (CFL) stability condition. In order to improve the accuracy and efficiency of FDTD simulation model, a parallel conformal FDTD algorithm based on graphics processor unit (GPU) acceleration technology and surface conformal technique was developed. The numerical simulation results showed that CUDA-implemented conformal FDTD method could greatly reduce computational time and the pseudo-waves generated by the ladder approximation. And the efficiency and accuracy of the proposed method are higher than the traditional FDTD method in simulating GPR wave propagation in two-dimensional (2D) complex underground structures.
      PubDate: Mon, 19 Aug 2019 00:05:14 +000
       
  • Surface Shape Detection with a Single Far-Field Intensity by Combined
           Amplitude and Phase Retrieval

    • Abstract: The efficiency of a reflector antenna highly depends on its surface shape. In order to ensure a good convergence, the conventional phase retrieval based shape detection schemes require that several far-field intensities be scanned, focused, or defocused. For large reflector antennas, the scanning process is time consuming. This paper proposes a new shape detection method that requires only single far-field intensity. Unlike existing shape detection methods, it retrieves both the amplitude and the phase, based on the fact that a deformed shape causes change not only in the aperture phase but also in the aperture amplitude. Through even-odd decomposition analysis, it is found that in the case of small and smooth deformation, “odd-phase” and “even-amplitude” can be directly recovered from one focused far-field intensity. This leads to the recovery of both the odd and the even parts of the antenna surface shape simultaneously. By combining amplitude retrieval and phase retrieval, this work achieves for the first time the shape detection with only one scan.
      PubDate: Sun, 18 Aug 2019 08:05:05 +000
       
  • Novel Gysel Power Dividers with Negative Group Delay Characteristics

    • Abstract: A novel Gysel power divider with negative group delay (NGD), good matching, and low insertion loss is proposed. Resistors connected with short-circuited coupled lines (RCSCL) are shunted at output ports of the Gysel power divider to obtain NGD characteristics, and another resistor is shunted at the input port to realize perfect input and output matching. To verify the proposed structure, an NGD Gysel power divider is designed and fabricated. At the center frequency of 1.0 GHz, the measured NGD times for different output ports are −1.94 ns and −1.97 ns, the input/output port return loss is greater than 38 dB, the insertion loss is less than 8.3 dB, and the isolation between output ports is higher than 41 dB. To enhance the NGD bandwidth, two RCSCL networks having slightly different center frequencies are connected in parallel, which provides wider bandwidth with good input matching characteristics.
      PubDate: Wed, 14 Aug 2019 17:05:01 +000
       
  • Design of Multilayer Frequency-Selective Surfaces by Equivalent Circuit
           Method and Basic Building Blocks

    • Abstract: An equivalent circuit method (ECM) is proposed for the design of multilayer frequency-selective surfaces (FSSs). In contrast to the existing ECMs that were developed mainly for the analysis of the properties of a given FSS, the presented ECM aims at providing the initial design parameters of an FSS from the desired frequency response. In this method, four types of basic FSS structures are used as the building blocks to construct the multilayer FSSs, and their surface impedances in both the normal- and the oblique-incidence situations are studied in detail in order to achieve more accurate equivalent circuit (EC) representation of the entire FSS. For a general FSS design with expected frequency response, the EC parameters and the geometrical sizes of the required basic building blocks can be synthesized from a few typical S-parameter (S11/S12) samplings of the response curves via a simple least-square curve-fitting process. The effectiveness and accuracy of the method are shown by the designs of a band-pass FSS with steep falling edge and a miniaturized band-pass FSS with out-of-band absorption. The prototype of one design is fabricated, and the measured frequency response agrees well with the numerical results of the ECM and the full-wave simulations.
      PubDate: Wed, 14 Aug 2019 09:05:03 +000
       
  • Experimental Verification of the Weibull Distribution in a Reverberation
           Chamber

    • Abstract: A Weibull distribution has been proposed for the probability density function (PDF) of the magnitude of the E-field in a reverberation chamber (RC). However, the Weibull distribution has two parameters, and if the parameters are position sensitive, the use of the Weibull distribution could be very limited. We investigate the sensitivity of the estimated parameters of the Weibull distribution in this study; the measurement results show that the parameters of the Weibull distribution depend on the positions of the antenna (or device under test), but not sensitive, and the statistical behavior of the parameters can be quantified. This means that the model of the Weibull distribution has a wider usable frequency range than that of the Rayleigh distribution and the statistical variation of the parameters needs to be considered.
      PubDate: Wed, 07 Aug 2019 08:05:11 +000
       
  • Research on Side Lobe Suppression of Time-Modulated Sparse Linear Array
           Based on Particle Swarm Optimization

    • Abstract: An efficient pattern synthesis approach is proposed for the synthesis of a time-modulated sparse linear array (TMSLA) in this paper. Due to the introduction of time modulation, the low/ultralow side lobe level can be obtained with a low amplitude dynamic range ratio. Besides, it helps reduce the difficulty of antenna feeding system effectively. Based on particle swarm optimization (PSO) and convex (CVX) optimization, this paper proposes a hybrid optimization method to suppress the grating lobes of the sparse arrays, peak side lobe level (PSLL), and peak sideband level (PSBL). Firstly, the paper utilizes the CVX optimization as a local optimization algorithm to optimize the elements’ switch-on duration time, which reduces the side lobe of the array. Secondly, with the PSBL as the objective function, the paper adopts the PSO as a global optimization algorithm to optimize the elements’ positions and switch-on time instant, which helps reduce the loss of sideband power caused by time modulation. With respect to the time modulation model, variable aperture sizes (VAS) and more flexible pulse-shifting (PS) schemes are used in this paper. Owing to the introduction of time modulation and CVX optimization, the proposed method is much more feasible and efficient than conventional approaches. Furthermore, it has better array pattern synthesis performance. Numerical examples of the TMSLA and comparisons with the reference are presented to demonstrate the effectiveness of the proposed method.
      PubDate: Wed, 07 Aug 2019 00:05:04 +000
       
 
 
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