bluuebunny/crossref_metadata_2025_split huggingface dataset:
Semifractal antenna with dual‐bands filtering and circular polarization properties using SCBP and MDGS structures
Authors: Naser‐Moghadasi M. , Sedgeechongaraluye‐Yekan T. 
Published: August 2015

ABSTRACTThis article proposes the novel design of a coplanar waveguide fed (CPW‐Fed) monopole ultra wideband (UWB) semifractal antenna with dual band‐notched specification and circular polarization (CP) attributes at ITU‐R (7.725–8.5 GHz). The semifractal patch of antenna is composed of unitcell which unitcell patterns form branchs of tree. The fractal geometry in radiator leads to have an effective impedance matching over the UWB spectrum. The Dual‐band filtering property can be adjusted finely by embedding a pair of L‐strips length inside the slotted conductor‐backed‐plane (SCBP) and mirrored defected ground structure (MDGS). Beside that, the length and position of L‐strips have great role in achieving CP in ITU‐R band. The actual size of the miniature and fabricated antenna is limited to 15 × 15 × 1 mm3 and it operates across 2.2–12.52 GHz for S11<−10dB, except the bandwidths of 3.1–3.6 for WiMAX and 5–6 GHz for WLAN. The antenna has CP bandwidth from 7.5 to 8.5 GHz for axial ratio less than 3 dB. The antenna's parameters were investigated to fully understand their affects. Main parameters achieved from this analysis enabled the optimization of the antenna's entire performances. The prototype was fabricated, to validate the performance of antenna, through simulations and measurements. The measured results certify the antenna radiates omnidirectionally and has a large impedance bandwidth, dual‐band rejection and CP property. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2483–2487, 2015
Miniature low SAR printed monopole antenna for mobile phone
Authors: Hossain M. I. , Faruque M. R. I. , Islam M. T. 
Published: August 2015

ABSTRACTA multiband compact printed monopole antenna is proposed for mobile phone. In this configuration, the antenna comprises a slotted rectangular‐shaped radiator, microstrip‐fed line, and a slotted ground plane on FR‐4 substrate. The total antenna dimensions with ground plane are 78 × 40 × 0.8 mm3. The measured results show that the proposed antenna has an impedance bandwidth 358.4 MHz (0.60–0.95 GHz, lower band), and 1 GHz (1.7–2.7 GHz, upper band), which can cover GSM 900 MHz, DCS 1800 MHz, PCS 1900 MHz, GSM 1900 MHz, UMTS 2100 MHz, Bluetooth 2400 MHz, WLAN II.b (2400 MHz), and LTE (2300–2400 MHz) bands. The proposed antenna shows very good radiation efficiencies and gain values and near omnidirectional radiation patterns at those frequency bands. Moreover, the proposed antenna produces lower specific absorption rate values in the human head than that of a dipole antenna, helical antenna, and planar inverted‐F antenna. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2471–2475, 2015
UWB loop antenna with stable broadside radiation characteristics
Authors: Yeo Junho , Lee Jong‐Ig 
Published: August 2015

ABSTRACTIn this article, a circular loop antenna with stable broadside radiation characteristics for ultrawideband (UWB) applications is proposed. It consists of a circular loop and circular sectors, and the circular sectors are used to directly match a 50‐Ω feed line over a UWB frequency band. The geometry of the proposed antenna is optimized to cover the 3.1–10.6 GHz UWB frequency band with stable broadside radiation patterns. The input impedance and voltage standing wave ratio (VSWR) characteristics of three different structures (a center‐fed circular loop with thin strips, a structure with circular sectors as an end‐truncated semicircular dipole, and the proposed loop antenna with circular sectors) are compared. The optimized proposed antenna is fabricated on a Teflon substrate. It exhibits a measured impedance frequency band of 3.08–12.27 GHz (120%) for a VSWR < 2, which ensures operation in the UWB band. Measured broadside gain is 3.0–7.0 dBi, and stable broadside radiation patterns are observed in the entire UWB band. Measured group delay remains almost constant with a variation of less than ±0.5 ns for the face‐to‐face orientation, and this indicates good time domain performance of the antenna. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2515–2519, 2015
A novel tunable microwave filter integrated power dividers using liquid crystal
Authors: Jiang Di , Chen Hui , Li Xiang , He Zhaosheng , Shen Mengkui 
Published: August 2015

ABSTRACTThis article presents design considerations of a tunable microwave filter integrated power divider based on highly anisotropic liquid crystals (LCs), which helps to reduce the circuit size. The proposed device comprising a thin LC layer between a ground plane and a directly coupled inverted microstrip line exhibits the equal power splitting function with a tunable bandpass response. The integrated device results in sharp rejection and smaller circuit area, as compared with the cascaded connection of an equal power divider and tunable microwave filter. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2539–2543, 2015
A 60 GHz transformer‐coupled neutralized low power CMOS power amplifier
Authors: Chen Bo , Shen Li , Gao Jianjun 
Published: August 2015

ABSTRACTA 60 GHz transformer‐coupled class AB 3‐stage low power amplifier (PA) has been implemented in a 130 nm standard RF‐CMOS process. The transformer, featuring direct impedance transformation and power combining is suitable for 60 GHz power amplifier design. This power amplifier operates from 1.2 V supply with 9.9 dB gain at 62 GHz, dissipates 58 mW DC power, and the reverse isolation is better than 39 dB from 50 to 67 GHz. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2487–2491, 2015
Band‐notched CPW‐FED UWB antenna using V‐shaped fractal elements
Authors: Esmati Zahra , Moosazadeh Mahdi 
Published: August 2015

ABSTRACTA simple procedure for designing a new fractal CPW‐fed monopole antenna with band‐notch function for ultrawideband applications has been proposed. The proposed antenna consists of V‐shaped patch with circular‐shaped elements and an elliptically‐shaped tapered ground plane. To create band‐notch function, V‐shaped structure is extruded on the patch from the throat of the feed. By cutting a pair of a quarter ellipse‐shaped slots in the ground plane, proper impedance matching is obtained; as a result much wider impedance bandwidth can be achieved, especially at the higher frequencies. The antenna is small in size (25 × 25 mm2) and has wide usable fractional bandwidth of more than 143% (3.15–19 GHz) defined by VSWR < 2, except at frequency band‐notched of 4.90–6.04 GHz. Moreover, Omnidirectional radiation pattern and acceptable antenna gain are obtained over the operating band. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2533–2536, 2015
A compact CPW‐FED wideband metamaterial antenna with EBG loading
Authors: Gupta Ashish , Chaudhary Raghvendra Kumar 
Published: August 2015

ABSTRACTTwo wideband CPW‐fed metamaterial antenna structures based on CRLH resonant approach are proposed and developed in this article. Antenna‐1 is basically an asymmetric CPW‐fed antenna, comprises of meandered line inductor, which is connected between patch and one of the CPW ground plane. Antenna‐2 is modified form of Antenna‐1 where conventional uniplanar electromagnetic bandgap (EBG) structures have been incorporated to enhance bandwidth of the antenna. It has been observed that Antenna‐2 is operating at 4.84–10.64 GHz equivalent to 74.9% measured fractional bandwidth with respect to Antenna‐1 with operating frequency 5.03–8.39 GHz equivalent to 50.1% fractional bandwidth. It is demonstrated that surface waves are suppressed effectively in the extended band. The radiation patterns of the Antenna‐2 are not influenced significantly with the incorporation of EBG and offers consistent radiation patterns throughout the operational bandwidth. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2632–2636, 2015
An accurate effective radius formula based on taguchi method for calculating resonant frequency of electrically thin and thick circular patch antennas
Authors: Li Xiaofeng , Wang Zhongbao , Fang Shaojun 
Published: August 2015

ABSTRACTA novel effective radius formula is proposed for accurately calculating the resonant frequency of circular patch antennas with electrically thin and thick substrates. The formula is optimized and obtained using the Taguchi method. It is widely suitable to circular patch antennas with the electrical substrate thickness h/λd range from 0.001 to 0.2 and the dielectric constants range from 1.0 to 10.2. Compared with previous resonant frequency analysis formulae, the resonant frequency results calculated using the proposed effective radius formula are in a better agreement with the simulated and measured results. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2567–2572, 2015
Hybrid dual‐antenna for the 3.6‐GHz LTE operation in the tablet computer
Authors: Wong Kin‐Lu , Chang Hsuan‐Jui 
Published: August 2015

ABSTRACTA hybrid dual‐antenna formed by an inverted‐F antenna (IFA) and an open‐slot antenna (OSA) for the 3.6‐GHz LTE operation (3.4–3.8 GHz) in the tablet computer is presented. The dual‐antenna is printed on a 0.8‐mm thick FR4 substrate and has a compact planar structure of 4 × 30 mm2. The dual‐antenna comprises a clearance region wherein the IFA is disposed and a metal pad wherein the OSA is embedded. The IFA's shorting strip is grounded through the metal pad to the device ground plane, so that an integrated compact dual‐antenna structure is obtained. As the IFA and OSA have different excitation mechanisms (electric‐current excitation on the IFA vs. magnetic‐current excitation on the OSA), the two antennas are expected to have different near‐field characteristics, thereby leading to decreased coupling. The proposed dual‐antenna has a measured isolation of better than about 12 dB over the operating band. The IFA and OSA have measured antenna efficiencies of about 72%–86% and 57%–78%, respectively. Good envelope correlation coefficient of less than 0.1 is obtained. Over the operating band, the ergodic capacity of the dual‐antenna is calculated to be about 9.8–10.6 bps/Hz. Details of the proposed dual‐antenna are presented. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2592–2598, 2015
A design of single‐ended to differential‐ended power divider for X band application
Authors: Yu Yongxia , Sun Liguo 
Published: August 2015

ABSTRACTA five‐port power divider with single‐ended input and two differential‐ended outputs is proposed. The frequency ranges from 9 to 11 GHz with a central frequency of 10 GHz. A stepped impedance line with open stubs is used between differential pairs for broadening the bandwidth and miniaturization of the divider. The divider is fabricated and the measurement results comply with the simulation. A proper performance for differential mode signal is achieved. The insertion loss is within 1.8 dB, the isolation is more than 15 dB, and the return loss is more than 11 dB. In addition, the common mode suppression is reached as well. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2669–2673, 2015
Wideband double‐negative reconfigurable metamaterial using a complementary split‐ring resonator with a via‐hole
Authors: Choi Jung Han , Jung Chang Won 
Published: August 2015

ABSTRACTWe demonstrate a wideband reconfigurable double‐negative metamaterial using a complementary split‐ring resonator with a via‐hole in a planar microstrip line. The resonator is made of quad‐rings, which are grounded using the via‐hole. By tailoring the quad‐rings with switches, reconfigurability was implemented and the isotropic nature was investigated. The equivalent circuit was proposed. The effective permittivity and permeability were extracted using the Ziolkowski method. Excellent agreements between the developed circuit model and experiment results were achieved. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2687–2690, 2015
A compact hut‐shaped printed antenna for super‐wideband applications
Authors: Tahir Farooq A. , Naqvi Aqeel H. 
Published: August 2015

ABSTRACTIn this article, a novel super‐wideband planar microstrip‐fed monopole antenna is investigated and designed. The antenna consists of a well‐optimized hut‐shaped radiating patch having a diamond‐shaped slot window at its center. To achieve nearly omnidirectional pattern, a partial ground plane consisting of an optimized slit exactly on the opposite of the feed line is used. Measurement results show that the impedance bandwidth for |S11|dB ≤ 10 dB is enhanced largely to 184.5% with a ratio bandwidth more than 24.8:1 (0.9 − 22.35 GHz). This, together with its nearly constant measured gain of 3.35 dBi ±1 dB over this entire band makes it a potential candidate for both ultra‐wideband and super‐wideband applications. Moreover, the proposed antenna has a compact size of 40 × 25 mm2 on 1.6 mm thick FR4 substrate with dielectric constant of 4.4. Details of the proposed antenna are described, and both theoretical and experimental results are presented. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2645–2649, 2015
Low cost electronic beam tilting of microstrip antennas by the use of tunable parasites
Authors: Dias Mauricio Henrique Costa , Freitas Vitor , Vuong Tan‐Phu 
Published: August 2015

ABSTRACTIn this work, parasitic elements are combined with inserted capacitances to tilt the radiated beam of a microstrip patch antenna. An application case at 2.45 GHz was considered for discussion. Realized gains up to 8 dBi and tilts within ±15° were achieved by the proposed configuration. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2710–2713, 2015
Zero‐biased diode Schottky detector for low cost preamplified millimeter‐wave imaging
Authors: Yang Fei , Wang Zongxin , Dou WenBin , Sun Zhongliang 
Published: August 2015

ABSTRACTDevelopment of a sensitive Schottky detector using zero‐biased diode (ZBD) for preamplified millimeter‐wave imaging is presented. Low noise amplifier gain and detector responsivity, key parameters to the imaging module, are analyzed to get the sensitivity performance characterization. The detector integrates one ZBD, stripline filtering and matching elements, and finline transition on a thin Rogers substract. Methodology used to detector design is described here, including the determination and optimization of the circuit geometrical and electrical parameters. A relatively good agreement between the simulations and the measurements has been found. At 92 GHz, linearity of 0.998 and detection responsivity of 4000 mV/mW dB are measured, respectively. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2690–2693, 2015
Isolated facial diplegia in Guillain–Barré syndrome: Bifacial weakness with paresthesias
Authors: Wakerley Benjamin R. , Yuki Nobuhiro 
Published: August 2015

ABSTRACTBifacial weakness with paresthesias (BFP) is a subtype of Guillain–Barré syndrome defined by rapidly progressive bilateral facial weakness in the absence of other cranial neuropathies, ataxia, or limb weakness. Many patients also complain of distal limb paresthesias and display diminished or absent deep tendon reflexes. BFP is a localized form of Guillain–Barré syndrome and is thought to be caused exclusively by demyelinating‐ rather than axonal‐type neuropathy. Patients with BFP do not display anti‐ganglioside IgG antibodies. Since it is rare, many physicians are unfamiliar with BFP, as bilateral facial weakness is more commonly associated with sarcoidosis, Lyme disease, or meningeal pathology. Many patients diagnosed with bilateral Bell palsy may instead have BFP. In this review, we highlight the clinical features of BFP and outline diagnostic criteria. Muscle Nerve 52: 927–932, 2015
Balance and coordination training, but not endurance training, enhances synaptophysin and neurotrophin‐3 immunoreactivity in the lumbar spinal cord after sciatic nerve crush
Authors: Bonetti Leandro Viçosa , Ilha Jocemar , Schneider Ana Paula Krauthein , Barbosa Silvia , Faccioni‐Heuser Maria Cristina 
Published: August 2015

ABSTRACTIntroduction: Numerous rehabilitation treatments have been shown to be useful for peripheral and central restoration after (PNI). Methods: After sciatic nerve crush, we investigated 4 weeks of endurance training (ET) and balance and coordination training (BCT) with sciatic function index, hind‐paw stride length, and spinal cord dorsal horn synaptophysin and neurotrophin‐3 immunoreactivity. Results: Our results demonstrated no significant differences between the non‐trained (NT), ET, and BCT groups in sciatic functional index, and in stride‐length analysis, but the ET showed higher values compared with the NT group. Synaptophysin immunoreactivity was higher in the BCT group compared with the NT group, and neurotrophin‐3 immunoreactivity in the BCT group was greater compared with the other groups. Conclusion: BCT can positively affect spinal cord plasticity after a (PNI), and these modifications are important in the rehabilitation process. Muscle Nerve 53: 617–625, 2016
Reservoir characterization in an underground gas storage field using joint inversion of flow and geodetic data
Authors: Jha B. , Bottazzi F. , Wojcik R. , Coccia M. , Bechor N. , McLaughlin D. , Herring T. , Hager B. H. , Mantica S. , Juanes R. 
Published: August 2015

SummaryCharacterization of reservoir properties like porosity and permeability in reservoir models typically relies on history matching of production data, well pressure data, and possibly other fluid‐dynamical data. Calibrated (history‐matched) reservoir models are then used for forecasting production and designing effective strategies for improved oil and gas recovery. Here, we perform assimilation of both flow and deformation data for joint inversion of reservoir properties. Given the coupled nature of subsurface flow and deformation processes, joint inversion requires efficient simulation tools of coupled reservoir flow and mechanical deformation. We apply our coupled simulation tool to a real underground gas storage field in Italy. We simulate the initial gas production period and several decades of seasonal natural gas storage and production. We perform a probabilistic estimation of rock properties by joint inversion of ground deformation data from geodetic measurements and fluid flow data from wells. Using an efficient implementation of the ensemble smoother as the estimator and our coupled multiphase flow and geomechanics simulator as the forward model, we show that incorporating deformation data leads to a significant reduction of uncertainty in the prior distributions of rock properties such as porosity, permeability, and pore compressibility. Copyright © 2015 John Wiley & Sons, Ltd.
Parallel implementation of spectral element method for Lamb wave propagation modeling
Authors: Kudela Pawel 
Published: August 2015

SummaryThe proposed spectral element method implementation is based on sparse matrix storage of local shape function derivatives calculated at Gauss–Lobatto–Legendre points. The algorithm utilizes two basic operations: multiplication of sparse matrix by vector and element‐by‐element vectors multiplication. Compute‐intensive operations are performed for a part of equation of motion derived at the degree of freedom level of 3D isoparametric spectral elements. The assembly is performed at the force vector in such a way that atomic operations are minimized. This is achieved by a new mesh coloring technique The proposed parallel implementation of spectral element method on GPU is applied for the first time for Lamb wave simulations. It has been found that computation on multicore GPU is up to 14 times faster than on single CPU. Copyright © 2015 John Wiley & Sons, Ltd.
Effect of Cognitive Load on Seating Posture in Children
Authors: Igarashi Go , Karashima Chieko , Hoshiyama Minoru 
Published: August 2015

AbstractAlthough children are frequently required to sit upright, it is often difficult to maintain this posture when performing cognitive tasks. Information about the relationship between a cognitive tasks and postural seating control is important for children to complete tasks more effectively. To determine the muscle activity and body sway of children in a seated posture while performing a cognitive task, changes in muscle activity and center of pressure (COP) were recorded while 4th grade children performed arithmetic tasks. Electromyography was recorded from the internal oblique and lumbar multifidus muscles, and the COP was recorded using a baropodometer placed on the stool. These variables were measured during easy (EA) and difficult (DA) arithmetic tasks. EMG activity decreased during the EA and DA tasks, while the COP was displaced in the DA task. The results of the arithmetic tasks were not related to the EMG or COP changes. Attention to maintain a seated posture may be reduced when children perform cognitive tasks. Therefore, it may be better to allow children to alter their posture especially when they are performing difficult tasks. In this research, we only used arithmetic tasks as the cognitive exercise, and therefore, other types of tasks should be examined. Copyright © 2015 John Wiley & Sons, Ltd.
A candidate gastric stem/progenitor cell marker revealed by genome‐wide analysis
Authors: Zhu Helen He , Zhuang Guanglei , Gao Wei‐Qiang 
Published: August 2015

AbstractDespite the important role of the gastric stem cell in tissue homeostasis and gastric carcinogenesis, its residence and identity remain poorly understood. In a recent paper in The Journal of Pathology, Vange et al suggest ASPM as a candidate stem/progenitor cell marker for oxyntic glands. Identification of ASPM was achieved by genome‐wide gene expression analysis of the micro‐dissected isthmus zone, where the majority of stem/progenitor cells are believed to reside. ASPM‐positive cells, scattered in the proliferative isthmus region, do not express most differentiated cell markers and are largely quiescent. Together with ASPM, 11 other genes that are uniquely expressed in the isthmus zone constitute a regulatory network downstream of the core transcription factor E2F1. The authors further demonstrated that up‐regulation of E2F1 and ASPM is associated with gastric cancers. This study provides novel candidates for future lineage‐tracing experiments that will lead to the ultimate discovery of bona fide gastric stem cell markers. Additionally, the E2F1–ASPM axis may represent a new mechanism for gastric carcinogenesis. Copyright © 2015 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.