bluuebunny/crossref_metadata_2025_split huggingface dataset:
A log‐periodic toothed trapezoidal antenna for RF energy harvesting
Authors: Simón Jorge , Flores‐Gonzalez Juan R. , González‐Salas Javier S. , Ordaz‐Salazar Francisco C. , Flores‐Troncoso Jorge 
Published: September 2015

ABSTRACTIn this work, the performance of a broadband log‐periodic toothed trapezoidal antenna is evaluated to know its potential for RF energy harvesting. The energy harvested by the antenna from the different wireless standards in urban areas can be converted into Direct Current and used to feed low power electronics. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:2765–2768, 2015
A multiband uniplanar antenna for LTE/GSM/UMTS, GPS, and WLAN/WiMAX handsets
Authors: Yang Li , Cui Yue‐Hui , Li Rong‐Lin 
Published: September 2015

ABSTRACTA multiband uniplanar antenna is proposed for mobile handsets. The multiband antenna covers three frequency bands: 687–976 MHz for LTE700/GSM850/900, 1195–1246 MHz for GPS (L2), and 1423–7665 MHz for GPS (LI), GSM1800/1900, UMTS2100, LTE2300/2600, WLAN2.4/5.5 GHz, and WiMAX3.5 GHz. The uniplanar antenna consists of a meander ring, an inverted‐S monopole, and a subring, and is printed on a thin substrate, suitable for ultraslim smartphone applications. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:2761–2765, 2015
Fabrication and small signal modeling of 0.5 μm InGaAs/InP DHBT demonstrating FT/Fmax of 350/532 GHz
Authors: Niu Bin , Wang Yuan , Cheng Wei , Xie Zi‐Li , Lu Hai‐Yan , Sun Yan , Xie Jun‐Ling , Chen Tang‐Sheng 
Published: September 2015

ABSTRACTAn InGaAs/InP three mesa double heterojunction bipolar transistor demonstrating ft/fmax of 350/532 GHz was fabricated on 3 inch wafer with a 0.5 μm emitter and a composite collector. Base resistance Rbb of around 19 Ω was achieved to sustain a relative high fmax in 0.5 μm linewidth device. Small signal equivalent circuit model was established, and good agreement between measured and simulated values was achieved. Effects of some key parameters were analyzed based on simulated small signal equivalent circuit model. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:2774–2778, 2015
Experimental study of silicon‐based microwave switches optically driven by LEDs
Authors: Zhao Deshuang , Han Yifei , Zhang Qiaoli , Wang Bing‐Zhong 
Published: September 2015

ABSTRACTThe feasibility of utilizing small‐size low‐cost commercial light‐emitting diodes (LEDs) to drive the optically controlled microwave switches (OCMS) is experimentally investigated. A series of experiments are performed within 0.5–5 GHz bandwidth by utilizing six kinds of LEDs and a 980 nm‐laser to drive the OCMS. The results show that white, red, and violet LEDs are three competitive candidates to replace high‐cost lasers as the controller of OCMS if their power density impinging on the silicon dice of the OCMS could be increased up to 100
. Additionally, the reason leading to high insertion loss of the OCMS driven by the LEDs is revealed. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:2768–2774, 2015
Microstrip patch antenna project with split ring resonator periodically arrayed on the substrate
Authors: da Silva José L. , de Andrade Humberto D. , Fernandes Humberto C. C. , da Silva Isaac B. T. , Júnior Idalmir de S. Q. , Pereira Jonathan P. P. , Neto Almir S. S. 
Published: September 2015

ABSTRACTThis article presents an investigation about the parameters of rectangular microstrip patch antennas with resonators on the antenna's substrate, through a experimental collection, it has been observed a simulation analysis and its verification by measured data. This investigation refers to two arrayed sets on the substrate, the first one with 16 resonators and the second one with 36. The substrate composition of the antenna have been based on the use of split ring resonators, periodically organized on arrays and confined on the substrate. By applying this proposal, it has been made an evaluation of return loss behavior related to the operation frequency, bandwidth, gain, and feature impedance, in which intended to compare the obtained values to each spacial disposition of the resonator elements. The result analysis demonstrated acceptable agreement between simulated and measured values. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:2715–2720, 2015
A loosely coupled distributed antenna array for lateral misalignment‐improved near‐field wireless power transfer system
Authors: Lee Wang‐Sang , Park Sungsoo , Lee Jaeho 
Published: September 2015

ABSTRACTA loosely coupled distributed antenna array for lateral misalignment‐improved near‐field power transfer system is presented. The characteristics of the proposed resonant coil are verified by the comparisons among the theoretical analysis, simulated results, and experimental measurements. Using the distributed loop structure, the uniform overall transfer range can be extended up to approximately 67% compared with the conventional square antenna according to the lateral misalignment of the receiving antenna at transfer distance. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:2829–2833, 2015
A compact low‐pass filter with ultrabroad stopband characteristics
Authors: Lan Siang‐Wen , Weng Min‐Hang , Chang Shoou‐Jinn , Hung Cheng‐Yuan 
Published: September 2015

ABSTRACTA compact low‐pass filter (LPF) with ultrabroad stopband characteristic is presented in this article. This filter mainly consists of a rectangular stub resonator and cumulative open‐circuited stubs, providing multiple transmission zeros to form a wide stopband region. Further, two open stub loads are simply adopted to improve the band selectivity. This fabricated LPF exhibits a 3 dB cutoff frequency (fc) at 1.74 GHz with an average low insertion loss of 0.25 dB and a broad stopband region from 2.6 to 22.8 GHz (10.8ƒc) under a high rejection level of 20 dB. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:2800–2803, 2015
An X‐band RLC matched power amplifier using quasi‐MMIC technology
Authors: An Sung Jin , Kim Dongsu , Yook Jong Min , Kim Sung Ryul , Lee Won Chul , Kim Jun Chul , Yook Jong‐Gwan 
Published: September 2015

ABSTRACTThis article presents an RLC matched power amplifier using quasi‐MMIC technology in the X‐band. The power amplifier consists of a GaN HEMT power device and several passive components including inductors, capacitors, resistors, and transmission lines using a silicon integrated passive device (IPD) process. The standard silicon process can drive the solution to cost down compared with conventional microwave monolithic integrated circuit (MMIC) technology. This technology using silicon IPDs provides small size matching networks close to MMIC dimensions. The input matching network using the RLC matched circuit is designed to obtain broadband characteristic and gain flatness. The dimensions of input and output silicon IPD are 1.5 mm × 1.2 mm and 1.9 mm × 2.2 mm, respectively, with a thickness of only 0.15 mm. The measured results show that the quasi‐MMIC power amplifier has a P3dB of more than 38.3 dBm with a drain efficiency of more than 51.2% in the frequency range from 8.2 to 10 GHz. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:2803–2807, 2015
A compact reconfigurable microstrip antenna with frequency and radiation pattern selectivity
Authors: Li Na , Leng Wen , Wang An‐Guo , Guo Tong‐Feng , Zhang Zhen‐Yu 
Published: September 2015

ABSTRACTA reconfigurable microstrip antenna with frequency and radiation pattern selectivity is presented. The proposed planar antenna consists of six symmetrical main radiating elements and 12 parasitic elements. By controlling the states of PIN diodes, the proposed antenna is capable of operating within 2.29–2.50 GHz, 2.48–2.69 GHz, and 2.77–2.91 GHz, respectively, and steering radiation patterns in the whole azimuth plane to six different directions. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:2848–2854, 2015
Gigabit passive optical networks and catv over hybrid bidirectional free space optics +20 km single mode fiber
Authors: Sousa Artur , Shahpari Ali , Ribeiro Vitor , Lima Mario , Teixeira António 
Published: September 2015

ABSTRACTThis article experimentally shows a gigabit passive optical network (GPON)+ community access television system (CATV) link, transmitting in 20 km of single mode optical fiber section or/and in free space. Bidirectional transmission of GPON traffic and CATV and further experimental apparatus is demonstrated and performed, based on signal transparency through the optical path, without optical‐electrical‐optical signal conversion between different media. The viability of such links is here analyzed by measuring the loss of data packets and the carrier‐to‐noise‐ratio value for the video signal overlay. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:2867–2871, 2015
Compact dual band‐notched UWB mimo antenna with shared radiator
Authors: Srivastava Garima , Kanuijia Binod K. 
Published: September 2015

ABSTRACTAn ultrawideband (UWB) multiple input and multiple output (MIMO) antenna having shared radiator with dual band rejection characteristics is presented in this article. The proposed antenna is based on the concept of dual polarization. The antenna consists of two tapered CPW feeds printed on one side of the substrate and a circular shared radiator on the other side. The radiator is shared between two antenna elements. High isolation between the antenna elements is achieved by introducing a rectangular slot in the circular radiator and an inverted Y‐shaped stub on the ground plane at an angle of 45°. The proposed antenna rejects the WiMAX and wireless LAN band of frequencies using elliptical split ring slots in the shared radiator. The diversity performance of UWB MIMO antenna is also studied. The antenna is fabricated on FR4 substrate and has a small size of 41 mm × 41 mm. The simulated and measured results are in good agreement which demonstrate its potential use in UWB portable devices. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:2886–2891, 2015
Circularly polarized frequency reconfigurable Koch antenna for GSM/Wi‐Fi applications
Authors: Reddy Venkateshwar V. , Sarma N. V. S. N. 
Published: September 2015

ABSTRACTA novel circularly polarized frequency reconfigurable Koch fractal boundary antenna is proposed. Initially, a Koch slot is etched on the Koch fractal boundary patch of larger dimension (48 × 48 mm2). Within the etched slot, an asymmetrical Koch fractal patch of smaller dimension (36 × 36 mm2) is embedded and switches are introduced along x and y‐directions to connect these inner and outer patch structures. By making ON/OFF switching of the diodes frequency reconfiguration is achieved. Measured results are in close agreement with the simulation results which demonstrates that the proposed antenna is well suited for GSM/Wi‐Fi wireless applications. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:2895–2898, 2015
Broadband unidirectional printed antenna with quad‐folded dipoles for circular polarization
Authors: Ding Xiaoxiang , Zhao Zhiqin , Yang Yaohui , Zhou Lin , Ouyang Jun , Liu Qing‐Huo 
Published: September 2015

ABSTRACTIn this article, a broadband unidirectional printed antenna with quad‐folded dipoles for circularly polarized radiation is proposed. The antenna consists of a trapezoidal feed structure, an annular transmission line and quad‐folded dipoles. An 80 × 80 mm2 reflector is used to achieve unidirectional radiation. Measured results indicate that the proposed design achieves an impedance bandwidth of 37.1% (1.82–2.65 GHz) for the voltage standing wave ratio <2.0 and a 3 dB axial ratio bandwidth of 35% (1.84–2.62 GHz), covering the third‐generation (3G, 1880–2125 MHz)/long‐term evaluation (1880–2400 MHz)/wireless local area network (2400–2480 MHz) bands. An average gain of 6.3 dBic is obtained in the operating band. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:2871–2876, 2015
Observation violet emission of microfiber knot resonator
Authors: Sulaiman Azlan , Harun Sulaiman Wadi 
Published: September 2015

ABSTRACTFlorescence violet upconversion emission was observed for the first time from erbium‐doped microfiber knot resonator (MKR), fabricated from flame brush technique. Sixty‐milliwatt pump power is in conjunction with 2‐m erbium‐doped fiber (EDF) as a gain medium. The 4‐cm microfiber was produced and used in constructing a MKR as a wave resonator and selector. The violet emission operated at 435 nm together with common EDF green upconversion operated at 545 nm with absorbance unit of 1725 AU and 5811 AU, respectively. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:2929–2931, 2015
A new focused antenna array with circular polarization
Authors: Jiang Yuhai , Geyi Wen , Sun Hucheng 
Published: September 2015

ABSTRACTThis article presents a new circularly polarized (CP) focused microstrip antenna array working at 2.45 GHz. To focus the energy of the antenna array to a target point, a CP testing antenna is introduced and placed at the target point. The distribution of excitations for the antenna array can be obtained by maximizing the power transmission efficiency between the antenna array and the testing antenna, which can then be realized by a feeding network. Both simulated and measured results are presented to demonstrate the focusing and CP performance of the antenna array. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:2936–2939, 2015
Enhanced performance using STBC aided coding for led‐based multiple input single output visible light communication network
Authors: Shi Jianyang , Wang Yiguang , Huang Xingxing , Tao Li , Chi Nan 
Published: September 2015

ABSTRACTLight‐emitting diode‐based (LED) visible light communication (VLC) has become a candidate in next generation ultrahigh‐speed indoor wireless local area network. Within this scenario, it is most likely for a receiver to obtain the signals from multiple LED sources, which in general brings about interference among the transmitters and may result in failure detection. In this article, space‐time block coding (STBC), as a representative multiple antenna techniques, is adopted to enhance the VLC network performance for its effective suppression on the intertransmitter interference. We experimentally demonstrate a multiple input single output VLC network consisting of two RGB‐LEDs. Using STBC‐OFDM Coding, a total throughput of 500 Mb/s is achieved and the free space transmission reach can be extended as long as 5 m. As far as we know, it is the fastest speed and longest distance in multiple antenna VLC network using STBC coding. Both theoretical simulation and experimental investigation reveal great improvements in the robustness, flexibility, and compatibility of a LED‐VLC network due to the appropriate coding scheme. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:2943–2946, 2015
Compact wideband bandpass filter with controllable bandwidth and suppression of the second passband using a trimode resonator
Authors: Ma Xing‐Bing , Jiang Ting 
Published: September 2015

ABSTRACTThis article presents a wideband bandpass filter with controllable bandwidth and suppression of adjoining second passband, in which four same open loop resonators are adopted, hereinto two resonators located at the middle are integrated into a single trimode resonator using two microstrip lines. One line is applied to adjust desirable passband bandwidth, and the other is used to achieve the suppression of the second passband and obtain a wider stopband. Good return loss and inserted loss are obtained using an optimization routine. This technique has high flexibility on setting bandwidth and suppressing the adjoining second passband. Two prototype filters are designed and fabricated. Good agreements between simulation and measurement are demonstrated. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:2939–2943, 2015
Incorporation of nonzero echo times in the SPGR and bSSFP signal models used in mcDESPOT
Authors: Bouhrara Mustapha , Spencer Richard G. 
Published: September 2015

PurposeTo analyze the effect of neglecting nonzero echo times (TEs) in the conventional model of multicomponent driven equilibrium single pulse observation of T1 and T2 (mcDESPOT).Theory and MethodsFormulations of the two‐component spoiled gradient recalled echo (SPGR) and balanced steady state free precession (bSSFP) models that incorporate nonzero TE effects are presented in the context of mcDESPOT and compared with the conventionally used SPGR and bSSFP models which ignore nonzero TEs. Relative errors in derived parameter estimates from conventional mcDESPOT, omitting TE effects, are assessed using simulations over a wide range of experimental and sample parameters.ResultsThe neglect of nonzero TE leads to an overestimate of the SPGR signal and an underestimate of the bSSFP signal. These effects can introduce large errors in parameter estimates derived from conventional mcDESPOT under realistic imaging conditions.ConclusionSPGR and bSSFP signal models accounting for nonzero TE effects should be incorporated into quantitative mcDESPOT analyses. Magn Reson Med 74:1227–1235, 2015. Published 2015. This article is a U.S. Government work and is in the public domain in the USA
Iron complexes as potential photocatalysts for controlled radical photopolymerizations: A tool for modifications and patterning of surfaces
Authors: Telitel Sofia , Dumur Frederic , Campolo Damien , Poly Julien , Gigmes Didier , Pierre Fouassier Jean , Lalevée Jacques 
Published: September 2015

ABSTRACTThis article reports on the presumably first use of iron complexes (FeC) as potential photocatalysts for controlled radical photopolymerization reactions (CRP2). Three compounds were designed and investigated. Good linear evolutions of the molecular weight (Mn) with the conversion were observed. A comparison was provided with a reference iridium (III) complex [Ir(ppy)3 where ppy stands for 2‐phenylpyridine]. The on/off photopolymerization experiments highlight the presence of dormant species and a re‐initiation on demand upon irradiation. This unique re‐initiation property was used for the modification of surfaces (hydrophilic/hydrophobic properties) and surface patterning as well as the synthesis of a block co‐polymer (PMMA‐b‐PBA). A comparative analysis of the behavior of these iron complexes in thermally and photochemically activated polymerization was provided. The chemical mechanisms were studied by steady state photolysis, laser flash photolysis, cyclic voltammetry, luminescence quenching, and electron spin resonance experiments. A catalytic cycle was proposed with two steps: (i) the oxidation of the FeC excited state by an alkyl halide and (ii) the reduction by the oxidized form (FeC°+) by an amine or the macroradicals leading to the regeneration of the catalyst. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 702–713
Highly active polymeric organocatalyst: Chiral ionic polymers prepared from 10,11‐didehydrogenated cinchonidinium salt
Authors: Hassan Md. Mehadi , Haraguchi Naoki , Itsuno Shinichi 
Published: September 2015

ABSTRACTSince few examples of 10,11‐didehydrogenated (3‐ethynyl) cinchona alkaloids have been utilized as organocatalysts in asymmetric reaction, we synthesized 10,11‐didehydrogenated cinchonidine. The 3‐vinyl group of cinchonidine was transformed into a 3‐ethynyl functionality. Based on the resulting 10,11‐didehydrogenated cinchonidine, the corresponding quaternary ammonium salt and its dimers were prepared. The ion‐exchange reaction between the quaternary ammonium salt and sodium sulfonate produced the quaternary ammonium sulfonate as a stable ionic compound. Chiral ionic polymers were then synthesized by the ion‐exchange polymerization of the 10,11‐didehydrogenated cinchonidinium salt dimer and a disulfonate. The chiral ionic polymers were found to be capable of efficiently catalyzing the asymmetric alkylation of N‐(diphenylmethylene)glycine tert‐butyl ester. The enantioselectivities obtained with the polymeric catalysts were higher than those obtained with the corresponding monomeric catalyst. Dimers of 10,11‐didehydrogenated cinchonidinium salts were prepared. Treatment of the dimer with disodium disulfonate gave the chiral ionic polymers, which showed high catalytic activity in asymmetric benzylation of N‐(diphenylmethylen)glycine tert‐butyl ester. The polymeric catalysts were reused several times without the loss of catalytic activity. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 621–627
Visible light‐induced thiol‐ene reaction: A new strategy to prepare Α,ω‐dithiol and Α,ω‐divinyl telechelic polythiolether oligomers
Authors: Ma Wenchao , Chen Dong , Liu Lianying , Ma Yuhong , Wang Li , Zhao Changwen , Yang Wantai 
Published: September 2015

ABSTRACTA new strategy is developed to prepare both α,ω‐dithiol and α,ω‐divinyl linear telechelic polythiolether oligomers by visible light induced thiol‐ene chemistry in the presence of a fac‐Ir(ppy)3 photoredox catalyst. Polythiolether oligomers of well‐defined end groups and controlled molecular weights have been successfully synthesized at varying monomer molar ratios of 1,4‐benzenedimethanethiol (BDMT) to diethylene glycol divinyl ether (DEGVE). 1H NMR and MALDI‐TOF MS analyses demonstrate that as‐prepared polythiolethers possess high end‐group fidelity, which is further supported by the successful polyaddition of polythiolethers bearing α,ω‐dithiol and α,ω‐divinyl groups. For example, with the α,ω‐dithiol‐ (Mn = 1900 g mol−1, PDI = 1.25) and α,ω‐divinyl‐terminated (Mn = 2000 g mol−1, PDI = 1.29) polythiolethers as macromonomers, the molecular weight of resulting polythiolether is up to 7700 g mol−1 with PDI as 1.67. The reactivity of the terminal thiol group is further confirmed by the addition reaction with N‐(1‐pyrenyl)maleimide. UV‐vis spectra and fluorescene measurements suggest that fac‐Ir(ppy)3 undergo a redox quenching process reacted with BDMT to generate thiyl free radicals. With these results, the mechanism of the thiol‐ene reaction catalyzed by photoredox catalyst is proposed. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 740–749
Effect of aluminum thickness and etching time of aluminum induced texturing process on soda lime glass substrates for thin solar cell applications
Authors: Ünal Mustafa , Nasser Hisham , Günöven Mete , Sökmen İlkay , Tankut Aydın , Turan Raşit 
Published: September 2015

AbstractIn this study, aluminum induced texturing (AIT) technique is used to increase light absorption in thin film by way of increasing the portion of the diffuse transmitted light (haze). For this purpose, various AIT process parameters such as starting aluminum thicknesses, annealing temperature and time, etching time, etchant's concentrations, and temperature of etching are known to affect the final texture. We have investigated the effect of aluminum thickness and etching time on AIT process while keeping the other parameters fixed. Our results show that by changing initial aluminum thickness and etching time, it is possible to control surface morphology of glass substrate and the resulting optical diffuse transmittance. In addition, diffuse transmittance is increased over the visible range of solar spectra and total absorption by a‐Si:H is increased. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)