bluuebunny/crossref_metadata_2025_split huggingface dataset:
An ultrathin penta‐band polarization‐insensitive compact metamaterial absorber for airborne radar applications
Authors: Bhattacharya Anamiya , Bhattacharyya Somak , Ghosh Saptarshi , Chaurasiya Devkinandan , Vaibhav Srivastava Kumar 
Published: August 2015

ABSTRACTIn this article, an ultrathin penta‐band polarization‐insensitive metamaterial absorber has been presented, which consists of an array of a closed ring embedded in a tetra‐arrow resonator. The proposed ultrathin (∼λ0/18 corresponding to the highest absorption frequency) structure exhibits five distinct absorption peaks at 3.4, 8.34, 9.46, 14.44, and 16.62 GHz with peak absorptivities of 98.6%, 96.6%, 90.1%, 97.8%, and 93.1%, respectively. Due to fourfold symmetry the structure provides nearly unity absorption for all polarization angles under normal incidence. The structure also exhibits high absorption peaks (∼80%) up to 45° incident angles for both TE and TM polarizations. Surface current and electric field distributions for different absorption frequencies have been analyzed to visualize the absorption mechanism of the structure. Finally, the structure has been fabricated and experimentally measured responses are in good agreement with the simulated ones. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2519–2524, 2015
Temperature dependance of elctromagnetic radiation from terahertz photoconductive antennas
Authors: Zangeneh‐Nejad Farzad , Barani Navid , Safian Reza 
Published: August 2015

ABSTRACTIn this article, a modified equivalent circuit model for analysis of terahertz (THz) photoconductive antennas has been introduced to investigate the effect of temperature on the performance of this device. Based on this modified equivalent circuit model, the effect of temperature on various parameters of a THz photoconductive antenna such as excited THz photocurrent, radiated electromagnetic field and optical‐to‐THz power conversion efficiency has been studied. The model predicts that an increase in the operational temperature of photoconductive antennas results in lower induced THz photocurrent, lower radiated electromagnetic field and also lower optical‐to‐THz power conversion efficiency which is in accordance with experimental results. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2475–2479, 2015
Analysis and design of a dielectric insular image guide
Authors: Jin Lukui , Lee Razak , Robertson Ian 
Published: August 2015

ABSTRACTIn this article, a detailed theoretical analysis of the dielectric insular image guide (DIIG) is presented to provide a solution for low‐loss millimeter‐wave (mm‐wave) transmission lines. The effective dielectric constant method is utilized to design a DIIG prototype in the Ka‐band, which is then fabricated using a standard low temperature cofired ceramic technique. Results from measurements agree well with theoretical calculations and simulations. A loss of 0.012 dB/mm at 35 GHz is achieved, which indicates great potential for further development to realize highly integrated low‐loss mm‐wave components and systems. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2465–2467, 2015
Compact substrate integrated waveguide six‐port directional coupler for X‐band applications
Authors: Venanzoni Giuseppe , Mencarelli Davide , Morini Antonio , Farina Marco , Losito Onofrio , Prudenzano Francesco 
Published: August 2015

ABSTRACTA substrate integrated waveguide six‐port directional coupler is designed and characterized. The circuit exploits a very compact size and good reflection and transmission characteristics, as it exhibits both return loss and isolation higher than 15 dB over a 13% bandwidth. The device is made by connecting all ports to a single junction which mixes all signals. Some prototypes have been built and experimental results show a very good agreement with simulations. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2589–2592, 2015
Research on the half complementary split‐ring resonator and its application for designing miniaturized patch antenna
Authors: Cai Yang , Qian Zuping , Cao Wenquan , Zhang Yingsong 
Published: August 2015

ABSTRACTIn this letter, a novel half complementary split‐ring resonator (HCSRR) is investigated, and the employment for designing miniaturized patch antenna is researched. Through parameter‐study, the proposed HCSRR shows almost the same resonant characteristic as the original CSRR structure. When the half‐miniaturized CSRR is sandwiched in the middle of half patch antenna, which sharing the same virtual magnetic wall with HCSRR, the resonant frequency of the patch antenna can be lowered in a much degree. To validate the proposed concept, the miniaturized antenna operating at 2.21 GHz is fabricated and measured. The measured results show good accordance with the simulated ones and stable radiation pattern of patch mode can be maintained, which validate the characteristic of the proposed HCSRR structure. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2601–2604, 2015
Novel quad‐band circularly polarized capacitive‐fed microstrip antenna for C‐band applications
Authors: Singh Dinesh Kumar , Kanaujia Binod Kumar , Dwari Santanu , Pandey Ganga Prasad , Kumar Sandeep 
Published: August 2015

ABSTRACTA novel quad‐band circularly polarized capacitive coupled stacked patch antenna with wideband characteristics is presented for C‐band applications (4–8GHz). In the proposed design, only two truncated patches with horizontal slits and inclined slot are stacked together to generate quad‐band circular polarization operation and broadband behavior. The proposed antenna has achieved a bandwidth of 55.46% in the frequency band of 4.97–8.49 GHz and the 3‐dB axial ratio bandwidths of 0.98%, 4.275%, 0.8869%, and 1.35% in four distinct bands of 5.1223–5.1729 GHz, 5.4710–5.7100 GHz, 6.2747–6.3306 GHz, and 7.6775–7.7822 GHz, respectively. The measured results show the good agreement with simulated results of the presented antenna and confirm the validity of design. The proposed antenna is useful for various C‐band applications. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2622–2628, 2015
Design of compact planar rat‐race and branch‐line hybrid couplers using polar curves
Authors: Joubert Johan , Odendaal Johann W. 
Published: August 2015

ABSTRACTAn approach where polar curves are used to miniaturize hybrid couplers is presented. The design of such couplers can be done with the optimization of a few parameters using full‐wave analysis software. The results show similar or better electrical performance for a rat‐race and branch‐line coupler with, respectively, a 75 and 50% size reduction. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2637–2640, 2015
A compact CPW‐fed wideband metamaterial antenna using Ω‐shaped interdigital capacitor for mobile applications
Authors: Mishra Naveen , Gupta Ashish , Chaudhary Raghvendra Kumar 
Published: August 2015

ABSTRACTIn this article, a compact bandwidth enhanced CPW‐fed metamaterial antenna is presented. The band broadening is accomplished by combining the resonant modes (n = 0, 1, 2). The antenna is operated in series resonant mode, and therefore, resonant characteristics can be controlled effectively by varying series parameters. Coupling among patches are responsible for originating number of modes which is made nearer to the original mode (n = 0 mode) to enhance the bandwidth. Proposed antenna offers measured fractional bandwidth of 54.3% at 3. 41 GHz (center frequency). Ω (Ohm)‐shaped IDC is used to provide the series gap which improves impedance matching significantly. It is illustrated that the zeroth‐order resonating frequency depends on the series parameters by demonstrating the equivalent circuit model. The antenna has an average peak gain of 2.36 dB and average radiation efficiency of 92.81%, throughout the operating band (S11 < −10 dB). The proposed antenna has the advantages of simple fabrication, compactness, and omnidirectional radiation pattern makes it suitable for modern wireless communication such as WLAN/Wi‐Fi (2.4–2.49 GHz), WiMAX (2.5–2.69 GHz, 3.4–3.6 GHz), Bluetooth (2.4–2.48 GHz). Furthermore, prototype of the antenna is fabricated and measured and is in good agreement with the simulated one. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2558–2562, 2015
A Miniaturized 3‐dB hybrid coupler using the comb line
Authors: Pei Guo‐Hua , Choi Hak‐Keun 
Published: August 2015

ABSTRACTIn this article, a comb‐line architecture is proposed for miniaturization of a 3‐dB hybrid transmission coupler. The comb‐line coupler uses a periodic structure of distributed capacitance and inductance, thereby reducing the physical length of the coupler compared with conventional structures. Using the above principle, a miniaturized 3‐dB comb‐line hybrid coupler (operational range 1.71–2.17 GHz) was designed and manufactured, and its performance was compared with that of a conventional 3‐dB hybrid coupler. The size of the 3‐dB comb‐line hybrid coupler was reduced by 22.6% while maintaining the same performance as a conventional general hybrid coupler. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2641–2645, 2015
CPW‐fed monopole antenna with reduced radiation hazards toward human head using metallic thin‐wire mesh for 802.11ac applications
Authors: Gunavathi N. , Sriramkumar D. 
Published: August 2015

ABSTRACTThis article presents a planar monopole antenna with reduced radiation hazard toward human head using thin‐wire mesh which is needed in smart phone (mobile) for less crowded 801.11ac (5 GHz Wi‐Fi) applications. The antenna consists of a rectangular radiating element with a particular rectangular part being removed from it to increase the electrical length of the antenna for miniaturization. CPW—feed and radiating element are printed on the topside of the double sided PCB. Radiation hazards toward human head has been reduced using a metallic thin‐wire mesh in the backside of the PCB. Orientation of metallic thin wire mesh play a vital role. It has been placed in such a way to disturb the fringing field coupled toward head direction (positive X direction). The proposed antenna offers an impedance bandwidth of 1.47 GHz from 4.35 GHz to 5.82 GHz with resonant frequency 5.18 GHz when it printed on an FR4‐epoxy substrate with dielectric constant (εr) of 4.4. It is over all in dimension of 21.7 × 25.5 × 1.6 mm3. It has been designed and optimized using parametric study on the geometrical dimensions are investigated using electromagnetic simulation software HFSS 13.0 (High Frequency Structure Simulator). © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2684–2687, 2015
Advantages of utilizing through‐silicon‐vias in SiGe HBT RF low‐noise amplifier design
Authors: Song Ickhyun , Cho Moon‐Kyu , Jung Seungwoo , Ju Inchan , Cressler John D. 
Published: August 2015

ABSTRACTThe benefits of using through‐silicon‐vias (TSVs) in silicon‐germanium (SiGe) heterojunction bipolar transistor (HBT) low‐noise amplifiers (LNAs) over the conventional wire bonding have been investigated for the first time. The parasitics associated with wire bonding can be significantly minimized with TSVs, thereby reducing the LNA performance degradation at the packaging level. To verify simulations and theoretical analysis, a prototype K‐band TSV‐integrated LNA was implemented in a SiGe HBT platform. The parasitic inductance of TSVs was effectively utilized as an adjustable matching element for the optimum LNA performance. The proposed LNA exhibits minimal degradation compared to the (unpackaged) LNA with probe‐supplied ground. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2703–2706, 2015
A novel broadband reflectarray antenna with lattice stubs on square element for Ku‐band application
Authors: Qotolo Sajjad Faraji , Hassani Hamid Reza , Naser‐Moghadasi Mohammad 
Published: August 2015

ABSTRACTIn this article, a single layer unit cell reflectarray antenna comprising a fixed square patch to which is attached a lattice of symmetric open ended stubs is proposed. The phase response of the proposed unit cell element is governed by the length of the lattice, providing more than 600° of reflection phase variation. The unit cell element of 0.54λ0 × 0.54λ0, has a thin dielectric substrate thickness of 0.036λ0 and is placed above an air layer making the overall unit cell thickness of 0.126λ0. A 15 × 15 elements Ku‐band reflectarray antenna is designed with an area of 18 × 18 cm2. The reflectarray is center fed by a linearly polarized pyramidal horn antenna. The planar reflectarray antenna is fabricated and has wide −1 dB gain bandwidth, about 20% covering 12.1–14.8 GHz. The measured antenna gain at 13.5 GHz is 25 dB which is equivalent to 39% efficiency. The proposed unit cell and the reflectarray antenna are simulated through CST and HFSS software packages. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2699–2702, 2015
Dual‐wideband U‐shape open‐slot antenna for the lte metal‐framed tablet computer
Authors: Wong Kin‐Lu , Tsai Chih‐Yu 
Published: August 2015

ABSTRACTThe open‐slot antenna is very suitable for applications in the metal‐framed tablet device, such as the tablet computer, to achieve a low profile with wideband or multiband operation. This article presents a U‐shape open‐slot (U‐slot) antenna with a low profile of 7 mm to the top edge of the metal‐framed tablet computer for the LTE operation. The U‐slot has a simple structure of length 70 mm and the two slot openings thereof are disposed at the metal frame. The U‐slot antenna is fed using an end‐shorted 50‐Ω microstrip feedline, with a wideband matching network embedded therein. The antenna can support a 0.5‐wavelength slot resonant mode supported by the U‐slot itself and a 0.25‐wavelength slot resonant mode created by the open‐slot radiator (denoted as Slot 1 in this study) formed between one slot opening and the microstrip feedline as a virtual shorting. By further using an inverted‐U strip connecting across the U‐slot, the antenna can create an additional open‐slot radiator (denoted as Slot 2 in this study) to generate a 0.25‐wavelength slot resonant mode at lower frequencies. The resonant modes supported by the U‐slot, Slot 1, and Slot 2 can form two wideband operating bands to cover the LTE operation in the 698–960 and 1710–2690 MHz bands. Details of the proposed U‐slot antenna and the effects of the inverted‐U strip connecting across the U‐slot and the matching network are addressed. Experimental results of the fabricated U‐slot antenna are also presented. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2677–2683, 2015
Are different measures of depressive symptoms in old age comparable? An analysis of the CES‐D and Euro‐D scales in 13 countries
Authors: Courtin Emilie , Knapp Martin , Grundy Emily , Avendano‐Pabon Mauricio 
Published: August 2015

AbstractThe Centre for Epidemiologic Studies of Depression (CES‐D) and the Euro‐D are commonly used depressive symptom scales but their comparability has not been assessed to date. This article aims to contribute to the literature comparing the drivers of depression in old age across countries by examining whether CES‐D (in its eight‐item short version) and Euro‐D are comparable. Data from the Survey of Health, Ageing and Retirement in Europe (SHARE, N = 15,487) covering 13 countries was used to examine the scales’ distributional properties, systematic differences between population subgroups, sensitivity and specificity, and associations with established risk factors for depression in old age. CES‐D and Euro‐D were strongly correlated (r = 0.6819, p < 0.000). However, agreement between the two scales was moderate. There were systematic discrepancies in scores by demographic characteristics. CES‐D captures a more extreme pool of depressed individuals than Euro‐D. Although associations with risk factors are always in the same direction, they are often stronger for CES‐D than Euro‐D. Findings highlight the need to be cautious when comparing depression levels and associations with risk factors between surveys using different measures of depressive symptoms. Copyright © 2015 John Wiley & Sons, Ltd.
Hematopoietic cyclooxygenase‐2 deficiency increases adipose tissue inflammation and adiposity in obesity
Authors: Adi Nikhil , Perriotte‐Olson Curtis , V. Desouza Cyrus , Ramalingam Ramesh , Saraswathi Viswanathan 
Published: August 2015

ObjectiveAdipose tissue (AT) macrophages mediate AT inflammation in obesity, and cyclooxygenase‐2 (COX‐2) is a major inflammatory gene. It was hypothesized that deletion of hematopoietic COX‐2 will inhibit AT inflammation in obesity.MethodsLethally irradiated wild‐type (WT) mice were injected with bone marrow (BM) cells collected from WT or COX‐2 knock‐out (COX‐2−/−) donor mice and fed a high‐fat diet for 16 weeks.ResultsThe mice that received BM cells from COX‐2−/− mice (BM‐COX‐2−/−) gained increased body weight, fat mass, and visceral AT (VAT) mass. These mice exhibited reduced inflammatory markers in the VAT stromal vascular cells (SVC). However, the inflammatory markers were increased in adipocyte fraction and/or whole VAT. The activation of ERK1/2 MAPK, a pro‐inflammatory signaling pathway, was increased in BM‐COX‐2−/− mice. The molecular markers of adipogenesis were increased in the VAT or adipocyte fraction. Wnt signaling markers which inhibit adipogenesis, including Wnt3A and DVL3, were reduced, and Wnt5a/b which promotes inflammation was increased in the VAT and/or adipocytes. Finally, an increase in hepatic triglyceride levels in BM‐COX‐2−/− mice was noted.ConclusionsThe data suggest that COX‐2 deletion in hematopoietic cells reduces SVC inflammation but increases VAT inflammation and promotes adiposity likely via altered Wnt signaling.
Deciphering the biochemistry and identifying biomarkers to multiple sclerosis
Authors: Martins‐de‐Souza Daniel , Farias Alessandro S. 
Published: August 2015

Multiple sclerosis is an idiopathic demyelinating disease of the CNS. Despite being extensively studied during the last decades, many molecular aspects of the disease are still to be elucidated. Moreover, biomarkers for treatment and early diagnosis are major issues to be tackled. In this edition of Kroksveen et al. (Proteomics 2015, 15, 3361–3369) present biomarker candidates for the early detection of multiple sclerosis. Despite the need for validation in larger sets of samples, this dataset contributes to resolve open questions associated to multiple sclerosis.
Pleistocene Ventifacts and Ice‐Marginal Conditions, New Jersey, USA
Authors: Demitroff Mark 
Published: August 2015

AbstractThe Pleistocene environment of the New Jersey Pine Barrens has been interpreted as either cool and moist, with boreal forest, or cold and dry, with semi‐desert conditions. The presence of ventifacts is often cited as perfunctory evidence for strong Pleistocene wind action and sparse vegetation. This study examines sites where ventifacts had been reported and identifies abundant pebble‐ to boulder‐sized samples with a wide suite of erosional forms. Faceting occurred when the land was sparsely vegetated, allowing abundant wind‐entrained abradants to etch gravel and rocks as a consequence of katabatic winds blowing off the nearby Laurentide Ice Sheet. Most ventifacts occur on upland surfaces and attest to geomorphic stability in this part of the region's otherwise low‐relief landscape. Ventifacts were reworked and incorporated within deposits attributed to periglacial mass movement, particularly during climatic amelioration. Aeolian features such as pavement einkante, scallops and weathering pits can evolve only where sustained wind velocities are very high, sand sources are abundant and vegetation is absent. The Pine Barrens' ventifacts provide evidence of cold, dry and windy conditions and aid in the interpretation of landscape evolution. Copyright © 2015 John Wiley & Sons, Ltd.
Doping efficiency and limits in (Mg,Zn)O:Al,Ga thin films with two‐dimensional lateral composition spread
Authors: Mavlonov Abdurashid , Richter Steffen , von Wenckstern Holger , Schmidt‐Grund Rüdiger , Lenzner Jörg , Lorenz Michael , Grundmann Marius 
Published: August 2015

AbstractWe have investigated structural, optical, and electrical properties of MgZnO:(Al/Ga) thin films in dependence on Mg and Al/Ga concentrations. For this purpose, thin films with two perpendicular, lateral composition gradients, i.e., the Mg composition is varied in one direction whereas the Al/Ga concentration is varied in a perpendicular direction were grown at by pulsed‐laser deposition (PLD) using a threefold segmented PLD target and 2‐inch in diameter c‐plane sapphire substrates. It has been found that compensation by intrinsic acceptors limits efficient doping to dopant concentrations of about . Further, the electrical data suggests, that the compensating defect is doubly chargeable hinting to the zinc vacancy as microscopic origin. Increasing the dopant concentration above leads to a degradation of electrical and structural properties.
Enhancement of surface electrical current on silicon via nanodiamond particles deposited by pulsed spray technique
Authors: Cicala Grazia , Massaro Alessandro , Velardi Luciano , Senesi Giorgio Saverio , Perna Giuseppe , Marzulli Domenico , Melisi Domenico , De Pascali Giuseppe , Valentini Antonio , Capozzi Vito 
Published: August 2015

The deposition of as‐received nanodiamond (ND) particles on silicon substrate was performed by the pulsed spray technique, using a dispersion of 250 nm ND in 1,2‐dichloroethane. A set of samples was sprayed by varying the number of pulses from 1 to 500. The morphology of the samples was characterized and monitored by means of optical, atomic force, and confocal microscopies. At a low number of pulses, sparse diamond particles were observed, whereas at a high number of pulses dense/quasi‐continuous ND layers were formed. The electrical conductivity measurements of surface silicon substrate evidenced a remarkable change for the presence of ND particles. This behavior is also found by theoretical simulations (finite element method). Finally, a comparison between the electrical resistances measured on these samples versus the pulse number and the inverse current density calculated as a function of the number of ND particles, showed a good agreement. The experimental results highlighted an increase of the electrical current by using a number of pulses <100, whereas the simulation results proved the enhancement of current density and its surface rectification by employing a specific number of particles. The current increased by increasing the temperature and during the heating–cooling cycles hysteresis was observed.(a) Scheme of the sprayed ND particles on silicon substrate, (b) 3D AFM image 5 × 5 μm2 of 10 pulses sample, (c) trends of measured R and calculated 1/J.
Positive stabilization for switched linear systems under asynchronous switching
Authors: Liu Jiao , Wang Dong , Wang Wei , Zhuang Yan 
Published: August 2015

SummaryThis paper is concerned with the positive stabilization for a class of switched systems under asynchronous switching signals. Because it inevitably takes some time to identify the active subsystem in the real systems and activate the corresponding controller, the switching of controllers lags behind that of subsystems, which arises the problem of the asynchronous switching. By analyzing the solution of dynamic systems, the mode‐dependent controllers are designed to guarantee the positivity and exponential stability for the resultant closed‐loop switched linear systems under asynchronous switching signals in continuous‐time and discrete‐time cases, respectively. Sufficient conditions for the existence of admissible state‐feedback controllers are developed, and the corresponding switching signals are designed. Furthermore, a synchronous switching phenomenon is discussed as a special case. Finally, numerical examples are given to illustrate the effectiveness of the results. Copyright © 2015 John Wiley & Sons, Ltd.