bluuebunny/crossref_metadata_2025 huggingface dataset:
A tool for assessing management capacity at the decentralized level in a fragile state
Authors: Newbrander William , Peercy Chavanne , Shepherd‐Banigan Megan , Vergeer Petra
Published: October 2011

Fragile states need assessment of decentralized management capabilities, not just of the central level, to design capacity‐building efforts focused on improving management. Improving the management capacity of health departments at the provincial or district level is just as critical as strengthening the central ministry in fragile states if a health system that effectively addresses the real health needs of the population is to be formed. This paper describes a management capacity assessment tool developed for use in fragile states. It uses a framework that describes six critical management areas: oversight and coordination; human resources; resource management; health financing; community involvement; and health information management. These core areas of health system management are assessed with regard to capacity in three core management functions: the capacity to plan, to implement, and to monitor and evaluate. The tool was applied to assess the management capacity of six counties in Liberia. The results helped differentiate the level of capacity of the different counties and clarify the actions required to strengthen the health system in the periphery. The assessment also allowed the prioritizing of county health offices with regard to the level of capacity building required to improve management. The tool also identified successes that can inform the design of future health programs in other county health offices. The tool can be applied to other challenging country situations to assess management capacity, which will help focus technical assistance to the health sector in fragile states. Copyright © 2011 John Wiley & Sons, Ltd.
Estimating surface sublimation losses from snowpacks in a mountain catchment using eddy covariance and turbulent transfer calculations
Authors: Reba Michele L. , Pomeroy John , Marks Danny , Link Timothy E.
Published: October 2011

Sublimation is a critical component of the snow cover mass balance. Although sublimation can be directly measured using eddy covariance (EC), such measurements are relatively uncommon in complex mountainous environments. The EC measurements of surface snowpack sublimation from three consecutive winter seasons (2004, 2005 and 2006) at a wind‐exposed and wind‐sheltered site were analysed to characterise sublimation in mountainous terrain. During the 2006 snow season, snow surface and near‐surface air temperature, humidity and wind were also measured, permitting the calculation of sublimation rates and a comparison with EC measurements. This comparison showed that measured and simulated sublimation was very similar at the exposed site but less so at the sheltered site. Wind speeds at the exposed site were nearly four times than that at the sheltered site, and the exposed site yielded measured sublimation that was two times the magnitude of that at the sheltered site. The time variation of measured sublimation showed diurnal increases in the early afternoon and increased rates overall as the snow season progressed. Measured mean daily sublimation rates were 0.39 and 0.15 mm day−1 at the exposed and sheltered sites, respectively. At the exposed site, measured sublimation accounted for 16% and 41% of the maximum snow accumulation in 2006 and 2005, respectively. At the sheltered site, measured seasonal sublimation was approximately 4% in 2004 and 2006 and 8% in 2005 of the maximum snow water equivalent. Simulated sublimation was only available for 2006 and suggested smaller but comparable percentages to the sublimation estimated from observations. At the exposed site, a total of 42 mm sublimated for the snow season, which constituted 12% of the maximum accumulation. At the sheltered site, 17 mm (2.2% of maximum accumulation) was sublimated over the snow season. Copyright © 2011 John Wiley & Sons, Ltd.
Landscape transformation of an Alpine floodplain influenced by humans: historical analyses from aerial images
Authors: Doering M. , Blaurock M. , Robinson C.T.
Published: October 2011

Natural floodplains are spatially heterogeneous and dynamic ecosystems but at the same time, a highly endangered landscape feature due to climate change and human impacts such as water storage, flood control and hydropower production. Flow is considered a master variable that shapes channel morphology and the heterogeneity, distribution, and turnover of floodplain habitats. Despite their highly dynamic nature, the relative abundance of different habitat elements (islands, gravel bars) in natural floodplains seems to remain relatively constant over ecological periods and is referred to as the shifting mosaic steady state concept. In this conceptual context, we analysed spatiotemporal changes in relative habitat abundance and channel complexity of an alpine floodplain from its near natural state in 1940 before water abstraction and levee construction until 2007 using historical aerial images. Within the first decades of impairment, the relative abundance of floodplain habitats that depend on flood and flow pulses such as parafluvial channels and islands shifted toward a greater abundance of terrestrial forest and grassland habitats. After 1986, the duration and frequencies of high‐precipitation events (>60 mm 24 h–1) triggering major, channel‐reworking floods increased substantially and caused a restructuring of the floodplain and decrease in the abundance of more terrestrial habitat types. These results are contrary to expectations of the shifting mosaic steady state concept yet suggest its potential application as an indicator of landscape transformation and human impacts on floodplain ecosystems. Last, the results raise the applied question as to whether an increased frequency of high flow events induced by climate change can contribute to floodplain restoration. Copyright © 2011 John Wiley & Sons, Ltd.
Melted snow volume control in the snowmelt runoff model using a snow water equivalent statistically based model
Authors: Bavera D. , De Michele C. , Pepe M. , Rampini A.
Published: October 2011

Snowmelt is an important component of the river discharge in mountain environments. In the past 40 years, the snowmelt dynamics has been mostly evaluated using degree‐day‐based models like the snowmelt runoff model (SRM). This model has no control on the volume of the melting snow, even if SRM includes as data input the snow‐covered area. This lack explains why the application of SRM may lead to inaccurate snowmelt volume estimations, even if the discharge volumes are accurately reproduced. Here we introduce in SRM the control on the melted snow volume and consider it in the determination of SRM parameters. The total snow volume, accumulated at the end of winter season, is evaluated by a snow water equivalent statistically based model, SWE‐SEM, and used as an estimate of the melting snow during the summer season. The benefit derived from the introduction of the control on the melting snow volume was investigated in the Mallero basin (northern Italy) for the 2003 and 2004 snow melting seasons. The analysis compares the model's results adopting different parameter sets, both considering and ignoring the control on the melting snow volume. Copyright © 2011 John Wiley & Sons, Ltd.
A Topological method for global optimization of clusters: Application to (TiO2)n (n = 1–6)
Authors: Tang Lingli , Sai Linwei , Zhao Jijun , Qiu Ruifeng
Published: October 2011

A new topological method is presented to generate the isomer structures of compound clusters with well defined covalent bonds. This method, combined with density functional theory, has been used to perform global optimization of (TiO2)n (n = 1–6) clusters. Our comprehensive search not only reproduces all of the known lowest‐energy structures reported in previous works but also reveals some new low‐energy structures. Some energetically unfavorable motifs that induce energy penalties are obtained and discussed. Based on the ground state structures of the anionic (TiO2)n. clusters, the electron affinities and photoelectron spectra are simulated and compared with available experimental data. © 2011 Wiley Periodicals, Inc. J Comput Chem, 2011
Histology, histochemistry and stereology of the adipose fin of Prochilodus lineatus
Authors: Alves Rebeca Mamede da Silva , Pereira Bruno Fiorelini , Pitol Dimítrius Leonardo , Senhorini José Algusto , Rocha Rita de Cássia Gimenes de Alcântara , Caetano Flavio Henrique
Published: October 2011

The adipose fin is small, nonpared, and usually located medially between the dorsal and caudal fin. Its taxonomic occurrence is very restrict; thus, it represents an important trace for taxon distinction. As it does not play a known vital physiological roll and it is easily removed, it is commonly used in marking and recapture studies. The present study characterizes the adipose fin of Prochilodus lineatus, as it is poorly explored by the literature. The adipose fin consists basically of a loose connective core, covered by a stratified epithelium supported by collagen fibers. At the epithelium, pigmented cells and alarm substance cells are found. Despite the name, adipocytes or lipid droplets are not observed on the structure of the fin. Microsc. Res. Tech., 2012. © 2011 Wiley Periodicals, Inc.
Expression of high‐molecular‐mass neurofilament protein in horse (Equus caballus) spinal ganglion neurons
Authors: Russo Domenico , Castellani Gastone , Chiocchetti Roberto
Published: October 2011

Spinal ganglion (SG) neurons are subdivided, on the basis of their cytoplasmic aspect at light and electron microscopy, into dark (D) and light (L) neurons. Numerous efforts have been made to find specific markers able to identify D and L neuronal cytotypes. The isolectin B4 (IB4), utilized to identify nonpeptidergic D neurons in mice, unfortunately, has not proved as effective in other species. The 200‐kDa neurofilament protein (NF200) is considered as a typical marker of L neurons in the rat, cat, and chick. The aim of this study was to analyze the histological, morphometric, and neurochemical characteristic of NF200‐immunoreactive (IR) horse SG neurons, to better characterize them morphologically and functionally. NF200‐IR neurons showed two levels (strong and weak) of staining intensity. Most (84%) strongly stained NF200‐IR neurons corresponded to L neurons, and showed similar bimodality as in the size distribution study, which seems to indicate a third population of neurons, in addition to the two populations (small and large) previously identified.

In triple‐staining experiments where NF200 was colocalized with IB4, substance P (SP), and neuronal nitric oxide synthase (nNOS) neuronal markers, most NF200‐IR neurons were single stained. On the contrary, most IB4‐, SP‐, and nNOS‐stained neurons were triple labeled and almost equally subdivided between strong and weak NF200‐IR with the latter being always smaller in size than strong NF200‐IR neurons. In conclusion, horse SG neurons display significant morphometric and neurochemical differences compared with those of rodents. Microsc. Res. Tech., 2012. © 2011 Wiley Periodicals, Inc.
Developmental Plasticity and the Origin of Novel Forms: Unveiling Cryptic Genetic Variation Via“Use and Disuse”
Authors: Palmer A. Richard
Published: October 2011

Natural selection eliminates phenotypic variation from populations, generation after generation—an observation that haunted Darwin. So, how does new phenotypic variation arise, and is it always random with respect to fitness? Repeated behavioral responses to a novel environment—particularly those that are learned—are typically advantageous. If those behaviors yield more extreme or novel morphological variants via developmental plasticity, then previously cryptic genetic variation may be exposed to natural selection. Significantly, because the mean phenotypic effect of “use and disuse” is also typically favorable, previously cryptic genetic variation can be transformed into phenotypic variation that is both visible to selection and biased in an adaptive direction. Therefore, use‐induced developmental plasticity in a very real sense “creates” new phenotypic variation that is nonrandom with respect to fitness, in contrast to the random phenotypic effects of mutation, recombination, and “direct effects” of environment (stress, nutrition). I offer here (a) a brief review of the immense literature on the effects of “use and disuse” on morphology, (b) a simple yet general model illustrating how cryptic genetic variation may be exposed to selection by developmentally plastic responses that alter trait performance in response to “use and disuse,” and (c) a more detailed model of a positive feedback loop between learning (handed behavior) and morphological plasticity (use‐induced morphological asymmetry) that may rapidly generate novel phenotypic variation and facilitate the evolution of conspicuous morphological asymmetries. Evidence from several sources suggests that handed behaviors played an important role both in the origin of novel forms (asymmetries) and in their subsequent evolution. J. Exp. Zool. (Mol. Dev. Evol.) 318B:466–479, 2012. © 2011 Wiley Periodicals, Inc.
Parapodial glandular organs in Spiophanes (Polychaeta: Spionidae)—studies on their functional anatomy and ultrastructure
Authors: Meiβner Karin , Bick Andreas , Müller Carsten H.G.
Published: October 2011

Parapodial glandular organs (PGOs) of Spiophanes (Polychaeta: Spionidae) were studied using light and electron microscopy. These organs are found in parapodia of the mid body region, starting on chaetiger 5 and terminating with the appearance of neuropodial hooks (chaetiger 14 or 15 in adult individuals). Large PGOs in anterior chaetigers display different species‐specific types of openings whereas small PGOs in posterior parapodia of the mid body region always open in a simple vertical slit. Each PGO is composed of three main complexes: (1) the glandular sac with several distinct epithelia of secretory cells and secretory cell complexes and the reservoir filled with fibrous material, (2) the gland‐associated chaetal complex (including the region of chaetoblasts and follicle cells, follicular canals, two chaetal collector canals, the combined conducting canal, the chaetal spreader including the opening of the glandular organ with associated type‐1 secretory cells, and the gland‐associated chaetae), and (3) a bilayered musculature surrounding the gland. A considerable number of different cell types are involved in the secretory activity, in the guidance of the gland‐associated chaetae, and in the final expulsion of the fibrous secretion at the opening slit. Among these different cell types the type‐5 secretory cells of the proximal glandular complex with their cup‐shaped microvilli emanating thick microfibrils into the lumen of the glandular sac are most conspicuous. Secretory cells with cup‐shaped microvilli being involved in the production of β‐chitin microfibrils have so far only been reported from some representatives of the deep‐sea inhabiting Siboglinidae (Polychaeta). We suggest that the gland‐associated chaetae emerging from inside the PGOs of Spiophanes are typical annelid chaetae formed by chaetoblasts and follicle cells. Functional morphology implies the crucial role of PGOs in tube construction. Furthermore, the PGOs are discussed in consideration of phylogenetic aspects. J. Morphol., 2012. © 2011 Wiley Periodicals, Inc.
Brain biochemistry in autopsied patients with essential tremor
Authors: Shill Holly A. , Adler Charles H. , Beach Thomas G. , Lue Lih‐Fen , Caviness John N. , Sabbagh Marwan N. , Sue Lucia I. , Walker Douglas G.
Published: October 2011

The pathology of essential tremor is increasingly being studied; however, there are limited studies of biochemical changes in this condition. We studied several candidate biochemical/anatomical systems in the brain stem, striatum, and cerebellum of 23 essential tremor subjects who came to autopsy, comparing them with a control population. Striatal tyrosine hydroxylase, a marker of dopaminergic neurons, was 91.7 ± 113.2 versus 96.4 ± 102.7 ng/mg (not significant) in cases and controls, respectively. Locus coeruleus dopamine beta‐hydroxylase, a marker of noradrenergic neurons, was not significantly different between the essential tremor and control groups. Parvalbumin, a marker of GABAergic neurons, was 199.3 ± 42.0 versus 251.4 ± 74.8 ng/mg (P = .025) in the pons in the region of the locus coeruleus of essential tremor subjects versus controls, whereas there was no difference in cerebellar parvalbumin. These results are supportive of a possible role for reduced GABAergic function in the locus coeruleus in essential tremor. The hypothesis that essential tremor represents early Parkinson's disease was not supported, as striatal dopaminergic markers were not reduced compared with control subjects. © 2011 Movement Disorder Society
Auraptene regulates gene expression involved in lipid metabolism through PPARα activation in diabetic obese mice
Authors: Takahashi Nobuyuki , Senda Mari , Lin Shan , Goto Tsuyoshi , Yano Masamichi , Sasaki Takao , Murakami Shigeru , Kawada Teruo
Published: October 2011

Scope: Peroxisome proliferator‐activated receptor‐α (PPARα) is a key regulator of circulating lipid level. Thus, various food‐derived compounds that activate PPARα as agonists have been screened and characterized.

Methods and results: We investigated the effects of auraptene, a citrus‐derived compound serving as a PPARα agonist in vitro, on abnormalities in lipid and glucose metabolisms. In high‐fat‐diet (HFD)‐fed KK‐Ay diabetic obese mice, auraptene treatment suppressed hyperlipidemia and triglyceride accumulation in the liver and skeletal muscle, and increased the mRNA expression levels of the PPARα target genes involved in fatty acid oxidation in the liver and skeletal muscle. Moreover, the adipocyte size in the auraptene‐treated mice was significantly smaller than that in the control HFD‐fed mice resulting in the improvement of HFD‐induced hyperglycemia and abnormalities in glucose tolerance.

Conclusions: These findings indicate that auraptene activates PPARα also in vivo and its treatment may improve abnormalities in lipid and glucose metabolisms, suggesting that auraptene is a valuable food‐derived compound for managing metabolic disorders.
A 60‐GHz CMOS receiver front‐end with integrated 180° out‐of‐phase Wilkinson power divider
Authors: Lee Jen‐How , Chen Chi‐Chen , Lin Yo‐Sheng
Published: October 2011

A 60‐GHz receiver front‐end with an integrated 180° out‐of‐phase Wilkinson power divider using standard 0.13 μm CMOS technology is reported.The receiver front‐end comprises a wideband low‐noise amplifier (LNA) with 12.4‐dB gain, a current‐reused bleeding mixer, a baseband amplifier, and a 180° out‐of‐phase Wilkinson power divider. The receiver front‐end consumed 50.2 mW and achieved input return loss at RF port better than −10 dB for frequencies from 52.3 to 62.3 GHz. At IF of 20 MHz, the receiver front‐end achieved maximum conversion gain of 18.7 dB at RF of 56 GHz. The corresponding 3‐dB bandwidth (ω3 dB) of RF is 9.8 GHz (50.8–60.6 GHz). The measured minimum noise figure (NF) was 9 dB at 58 GHz, an excellent result for a 60‐GHz‐band CMOS receiver front‐end. In addition, the measured input 1‐dB compression point (P1 dB) and input third‐order inter‐modulation point (IIP3) are −20.8 dBm and −12 dBm, respectively, at 60 GHz. These results demonstrate the adopted receiver front‐end architecture is very promising for high‐performance 60‐GHz‐band RFIC applications. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2688–2694, 2010; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25559
Compact, printed mobile‐unit antenna for 2.4 and 5 GHz WLAN applications
Authors: Su Saou‐Wen , Chang Fa‐Shian
Published: October 2011

A simple yet effective, printed mobile‐unit antenna aimed at providing dual‐WLAN‐band operation in the 2.4 and 5 GHz bands and with a small form factor is presented.The antenna comprises a folded monopole and a small antenna ground, all printed in a single‐layered, FR4 substrate with the overall dimensions 8 mm × 25 mm. The frequency ratio of the dual‐resonant (the upper over the lower) modes can easily be manipulated by adjusting the antenna tuning portion. In addition, the antenna can be fed by utilizing a common mini‐coaxial cable, allowing it to be flexibly deployed inside versatile wireless electronic devices as an internal antenna. Details of a design prototype are described and discussed in the article. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2648–2653, 2010; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25561
Dual‐band circular slot antenna design for circularly and linearly polarized operations
Authors: Chiang Meng‐Ju , Hung Tian‐Fu , Bor Sheau‐Shong
Published: October 2011

The dual‐band circular slot antenna utilizing the embedded arc‐shaped metallic strip for the circularly polarized (CP) and linearly polarized (LP) operations is presented in this letter. The experimental results show that the resonant frequency of low‐band for CP mode is utilized the protruded arc‐shaped metallic strip, which extends current route to make the fundamental resonant mode shifted to the lower frequency band. The high‐band for LP mode, which has the similar current distribution to that of the fundamental mode of the conventional circular slot, is employed the first‐higher order resonant mode of the circular slot. Two measured input impedance bandwidths of the proposed design are 23.2% and 18.8%, respectively, and the measured bandwidth of low‐band with an axial ratio (AR) of less than 3.0 dB is 14.5%. The operating bands show the broadside radiation patterns with 1.7–2.7 dBic CP gain and the peak antenna gain of 3.6–4.3 dBi, respectively. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2717–2721, 2010; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25562
A low‐phase‐noise CMOS quadrature VCO with PMOS back‐gate coupling
Authors: Yeh Mei‐Ling , Lin Yao‐Chian , Liou Wan‐Rone , Kuo Sheng‐Hing , Roblin Patrick , Chang Chung Cheng
Published: October 2011

A new PMOS backgate quadrature voltage controlled oscillator (QVCO) is designed and implemented using TSMC 0.18 μm 1P6M CMOS technology.The phase noise of the PMOS back‐gate coupled QVCO operating at 1.5 V is measured to be −100 dBc/Hz and −125.08 dBc/Hz at 100 KHz and 1 MHz offset, respectively, for a low power consumption of 15 mW. The backgate QVCO demonstrates a wide frequency tuning range, a low phase noise, and a low power consumption. The corresponding figure‐of‐merit of the QVCO is −186 dBc/Hz. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2682–2685, 2010; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25564
All‐optical pulse repetition frequency divider utilizing an injection‐unlocked Fabry‐Perot laser diode
Authors: Zhang Mingjiang , Liu Tiegen , Wang Anbang , Wang Yuncai
Published: October 2011

We propose and demonstrate an all‐optical pulse repetition frequency divider based on the nonlinear period‐one oscillation of a Fabry‐Perot laser diode (FP‐LD).By adjusting the injection power of input optical pulses and detuning the wavelength of the FP‐LD, frequency‐divided optical pulses including divide‐by‐two and divide‐by‐three output can be readily achieved with suppressed phase noise over wide frequency range. For an 18‐GHz pulse train, we experimentally obtain 9‐GHz optical pulses train with phase noise of −105.6 dBc/Hz and 6‐GHz optical pulses train with phase noise of −105.5 dBc/Hz, separately. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2641–2643, 2010; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25565
Improved NURBS MOM‐PO method for analyzing antenna around electrically large platform
Authors: Huang Kai , He Zhi‐Li , Liang Chang‐Hong
Published: October 2011

The hybrid method of moments and physical optics (MOM‐PO) based on nonuniform rational B‐spline (NURBS) modeling represented a suitable approach for dealing with electromagnetic (EM) radiation problems because of its higher efficiency and more accurate modeling than Triangle MOM‐PO method.However, the invalidation in existing NURBS MOM‐PO method occurs when the distance between antenna and scatterer is less than one wavelength. The reason is analyzed in detail in this article. This article introduces an improved NURBS MOM‐PO method to overcome this problem. Ludwig integral combining with stationary phase method is utilized to calculate the integral of PO currents. Thus, both the efficiency and validity are ensured. Numerical results demonstrate that accurate results can be achieved efficiently in electrically large EM radiation problems by using the present method. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2675–2679, 2010; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25569
EpsiMu, A toolkit for permittivity and permeability measurement in microwave domain at real time of all materials: Applications to solid and semisolid materials
Authors: Ba Doudou , Sabouroux Pierre
Published: October 2011

In this article, we present a very simple toolkit for permittivity and permeability measurement in the microwave region in real time. This kit contains a coaxial cell and a dedicated software compatible with any Vector Network Analyzer (VNA) for the reconstruction of permittivity and permeability data. The customizing design of the coaxial cell depends on the applications and material forms. The dedicated software for overall cells reconstructs directly in real time the permittivity and the permeability from the S‐parameters measured. The Nicolson & Ross‐Weir algorithm is using after a de‐embedding process done by modeling our cell with an identity card (IC). The novelty of our method is that, after calibration process of the VNA to remove the cable effect, the measurement of the permittivity and permeability were done directly after only one measurement in real time. To validate the accuracy of this new measurement process for new applications, we reconstruct the permittivity of two material forms (dielectric or/and magnetic solids, semisolid). This new toolkit is called EpsiMu (www.epsimu.fr). © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2643–2648, 2010; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25570
An optimum superconducting ultra‐wideband bandpass filter at VHF band
Authors: Chen Wei , Guo Xubo , Cao Bisong , Zhang Xiaoping , Wei Bin , Zhang Ying , Lu Xinxiang
Published: October 2011

A highly selective superconducting ultra‐wideband filter with a passband from 125 to 260 MHz is designed and demonstrated using a microstrip structure. The filter is designed according to a circuit model for an optimum short‐circuited stub transmission‐line filter and consists of 10 shunt short‐circuited stubs separated by connecting lines. The short‐circuited stubs are quarter‐wavelength long, and the connecting lines are half‐wavelength long. The filter is realized on two 3‐inch YBCO/LaAlO3 substrates, which are connected by two bonding wires. The short‐circuited stubs are grounded via two grounding pads that are attached to the box wall by a number of SiAl bonding wires. The measured results exhibit a selective filtering characteristic equivalent to a 19‐pole Chebyshev filter and a low insertion loss of less than 0.1 dB at center frequency without tuning. Furthermore, the experimental results of the filter are in good agreement with the simulated ones. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2639–2641, 2010; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25571
A flexible RF transmitter module based on flexible printed circuit board by using micro‐machining fabrication process
Authors: Myoung Seong‐Sik , Kim Seon‐Il , Jung Joo‐Yong , Lim Dae‐Ho , Jang Jeensang , Kim Yong‐Jun , Yoo Jong‐Gwan
Published: October 2011

This article presents a flexible RF transmitter module based on flexible printed circuit board (FPCB).The polyimide with micro‐machining fabrication technique is employed for realization of FPCB to achieve the high flexibility as well as low loss at microwave frequency band. The active devices in the proposed flexible RF transmitter are design with InGaP/GaAs hetero‐junction bipolar transistor monolithic microwave integrated circuit process, and the passive devices such as the filter and interconnection lines are fully integrated on the FPCB board to avoid use of external off‐chip components for maximized flexibility. The FPCB transmitter module is designed for a short‐distance sensor network based on OFDM communication system, and the measured conversion gain and error vector magnitude of the fabricated flexible transmitter are 27 dB and −32 dB, respectively. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2636–2639, 2010; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25572
A novel dual‐layer high‐directivity directional coupler using printed metamaterial MS/NRI coupled‐line
Authors: Zhao Shiwei , Tang Zongxi , Dai Wei , Zhang Biao
Published: October 2011

A dual‐layer, multi‐aperture and multi‐section asymmetric printed metamaterial MS/NRI coupled‐line coupler is presented. The configuration consists of two‐layer back‐to‐back substrates with five small coupling apertures on the center ground plane. In addition, asymmetric coupled‐line sections connected in cascade with the coupling decreasing gradually from one end to the other. This novel dual‐layer coupler with high directivity can operate in wider bandwidth. Furthermore, it has smaller size and lower insertion loss. The circuit area of the proposed coupler is only 70% of that of the conventional dual‐layer coupler. Simulated and experimental results of the coupler exhibited a coupling of about −15 dB, isolation of about −50 dB, and directivity of about 35 dB at the design frequency from 3.25 to 5 GHz (with better than 45 dB directivity over 500 MHz). © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2706–2708, 2010; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25573
Modeling of radio‐over‐fiber links for 802.11g wireless local area networks
Authors: Sittakul V. , Cryan M. J.
Published: October 2011

This article proposes the use of cosimulation between Matlab/Simulink and Rsoft Optsim to model a radio‐over‐fiber (RoF) link for 802.11g wireless local area network (WLAN) applications. First, a RoF link is modeled based on the experimental results of binary phase shift keying data transmission. Then, orthogonal frequency division multiplexing (OFDM) data in frame format will be created using Matlab/Simulink to be transmitted over the same modeled RoF link. Results show that it is possible to model an 802.11g WLAN data over the RoF system using cosimulation software and the OFDM data transmission was successfully simulated and the constellation diagram and bit error rate are shown. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2672–2675, 2010; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25575
Drawing an ultra‐low loss all‐solid photonic bangap fiber for ytterbium ASE suppression
Authors: Yan Pei‐Guang , Zhao Jian , Ruan Shuang‐Chen , Yu Yong‐Qin , Shu Jie , Wu Xu , Ding Jin Fei , Wei Hui‐Feng , Luo Jie
Published: October 2011

A passive all‐solid photonic bandgap fiber (PBGF) was fabricated for ytterbium ASE controllable filtering.By direct adjustment of the fiber out‐diameter in drawing process, we can tune the stop‐band of ytterbium ASE to the desirable wavelength region. Our simulation results show a good agreement with measured bandgaps. The fiber is single mode and has a steep “cutting edge” in favor of ASE suppression. The measured transmission loss is 0.41 dB/km at wavelength of 1.55 μm within the longer wavelength bandgap, which is believed the lowest loss level of all‐solid PBGF reported to the best of our knowledge. Its “stop‐band” lies just in the range of 1.03–1.14 μm and shows a perfect ASE suppression by using only 0.2 m length of fiber. It provides a costless and feasible way to build the gain‐controllable laser with the nowadays mature conventional ytterbium‐doped fiber and such passive PBGF fiber. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2629–2632, 2010; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25578
A design of low‐profile triband antenna for emergency call system application
Authors: Kim Jeong‐Hoo , Kim Dong‐Zo , Lee Moon‐Que , Min Sang‐Bo , Lee Han‐Lim , Yu Jong‐Won
Published: October 2011

This article presents a design of a low profile triband antenna operating at three frequency bands (900, 1575, and 1800 MHz). The proposed antenna consists of two curved folded dipoles, a ceramic patch antenna, and a diplexer. Having the proposed antennas uniquely shaped, the total dimension of the structure requires very small space. The antenna shape is designed to improve the overall performance and the spatial efficiency. A diplexer following two folded dipole antennas can transfer the signal by using only one cable and thus, a great portion of the cost required for real application can be reduced. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2798–2801, 2010; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25580
Cavity backed dual slot antenna for gain improvement
Authors: Li Jin Xin , Luo Guo Qing , Liang Yaping , Li Wen Jun , Dong Lin Xi , Sun Ling Ling
Published: October 2011

A simple method of gain improvement for the cavity backed slot antenna based on the substrate integrated waveguide technique has been presented in this article. By using dual slot at the cavity edges to substitute a single slot at the cavity center as the radiating element, gain of the cavity backed slot antenna has been improved about 1.7 dB whereas its total size is little reduced. The proposed antenna has high radiation performance and keeps the advantages low profile, easy integration, and low cost fabrication. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2767–2769, 2010; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25582
Implementation and investigation of a dual‐frequency antenna
Authors: Hong Tao , Gong Shu‐Xi , Liu Ying , Xu Yun‐Xue
Published: October 2011

The planar rectangular split‐ring resonator is applied to design the printed dipole antenna with a requirement of dual frequency in this letter.A dual‐frequency antenna example is given, which works at 1.7 and 4.0 GHz. Any pair of working frequencies can be obtained by the presented technique. The antenna is simulated and fabricated. Its radiation characteristics including impedance bandwidth, radiation patterns, and gain are simulated, measured, and compared. The presented antenna has attractively good performances that the radiation patterns at dual frequencies are both dipolar. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2765–2767, 2010; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25583
Multiple carrier ultra‐wideband systems using an optical pulse modulation scheme
Authors: Lin Wen‐Piao , Hsu Yu‐Fang
Published: October 2011

This study proposes a new optical pulse modulation scheme for multiple carrier ultra‐wideband (MC‐UWB) wireless systems to achieve a reliable high‐bit‐rate transmission. The scheme can decrease the system complexity and lowering cost. Moreover, the UWB receiver is adapted with a modified single‐user correlation detector to recover original data signal by a narrow carrier spacing. Finally, we set up a practical experimental system to prove our proposed scheme. Experiment results demonstrate that the scheme can provide high spectral efficiency and reduce interference noise for MC‐UWB wireless communications. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2735–2738, 2010; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25584
A dual‐band divide‐by‐2 injection locked frequency divider in 0.35‐μm SiGe BiCMOS
Authors: Jang Sheng‐Lyang , Shih Chih‐Chieh , Chang Chia‐Wei , Liu Cheng‐Chen , Huang Jhin‐Fang
Published: October 2011

A fourth order resonator has been implemented to design an injection locked frequency divider (ILFD) implemented in a 0.35‐μm SiGe 3P3M BiCMOS process. The ILFD is realized with a cross‐coupled HBT LC‐tank oscillator with switched varactor bias for frequency band selection. The LC tank is a 4th order resonator and it can operate with two tunable frequency bands. Measurement results show that at the supply voltage of 1.25 V, the free‐running frequency can be from 3.22 (6.76) to 3.41 (7.53) GHz for the low‐(high‐) frequency band. The divide‐by‐2 operational locking range can be from 6.3 (12.8) to 6.95 (15.3) GHz for the low‐(high‐) frequency band. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2762–2765, 2010; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25586
High‐gain, short‐circuited six‐monopole‐antenna system for concurrent, dual‐band WLAN access points
Authors: Su Saou‐Wen
Published: October 2011

A high‐gain, short‐circuited multimonopole antenna system for wireless access points in the concurrent 2.4 and 5 GHz WLAN bands is presented. The antenna system mainly comprises a circular antenna ground and six short‐circuited, single‐band monopole antennas, among which the three antennas are designated for 2.4 and 5 GHz operation respectively. The monopole antennas are set in a sequential, rotating arrangement on the antenna ground, and the 2.4 and 5 GHz antennas are facing each other one by one. Experimental results show that well port isolation can be obtained between the antenna ports with high‐gain properties over the 2.4 and 5 GHz bands. A design prototype is elaborated and discussed in the article. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2728–2732, 2010; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25588
Wideband and low‐profile antenna for mobile terminals
Authors: Zhao Anping
Published: October 2011

In this article, a low‐profile and wideband antenna for mobile terminal is proposed by using a unique direct feed approach.In particular, the approach consists of a cut, a patch, and two vertical slots. It is found that both the patch and slot play an important rule in improving the impedance bandwidth of the antenna. Antenna prototypes were made and good agreement between the simulation and measurement results were obtained. The measured impedance bandwidth of the antenna at −6 dB level is from 0.78 to 3.95 GHz, which is sufficient to cover most of the current radio systems. In addition, a frequency‐notched operation can be easily achieved by opening an extra slot on the ground plane. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2724–2728, 2010; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25589
Compact wideband circularly polarized rectangular dielectric resonator antenna with dual underlaid hybrid couplers
Authors: Pan Yongmei , Leung Kwok Wa , Lim Eng Hock
Published: October 2011

A compact wideband circularly polarized rectangular dielectric resonator antenna (DRA) with dual underlaid hybrid couplers is investigated for the first time.As no extra footprint is needed for the couplers, the proposed antenna is very compact. The dual hybrid couplers are connected to generate four quadrature signals that are fed to four sequentially rotated excitation strips stuck on the four side walls of the DRA. It is found that the 3‐dB axial‐ratio bandwidth of the proposed antenna can be as wide as 27.7%. The reflection coefficient, radiation pattern, and antenna gain of the proposed antenna are studied, and reasonable agreement between the measured and simulated results is observed. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2789–2791, 2010; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25591
Band‐notched design of the planar monopole antenna for WLAN/WiMAX applications
Authors: Chen Kang‐Kang , Zhao Ji‐Xiang
Published: October 2011

A simple printed monopole antenna with tunable slots is proposed for wireless local area network (WLAN) and worldwide interoperability for microwave access (WiMAX) applications.The antenna structure consists of a semicircular ground and a rectangular patch with four round corners. By etching a couple of slots in the patch, the notched band from 3.7 to 4.8 GHz can be obtained. Furthermore, by adjusting the length and position of the slot, we make the notched band tunable both the center frequency and bandwidth. The proposed antenna is successfully designed and measured. The measured 10 dB bandwidth for return loss covers both the 2.4/5.2/5.8 GHz WLAN bands and 2.5/3.5/5.5 GHz WiMAX bands. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2782–2786, 2010; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25593
A novel miniature monopole tag antenna for passive UHF RFID applications
Authors: Liu Hsien‐Wen , Ku Chia‐Hao , Yang Chang‐Fa , Wang Te‐Shun
Published: October 2011

A novel miniature monopole tag antenna for passive Ultra‐High Frequency (UHF) radio frequency identification (RFID) operation is presented.The antenna possesses a two‐sided structure that is printed on an FR4 substrate and fed by a 50‐Ω microstrip line. By properly using helical strips and vias, the antenna size can be reduced to a small volume of 10 (L) × 9.5 (W) × 0.8 (H) mm3 to be easily integrated within various portable devices. A miniaturized quasi‐lumped circuit is also designed to attain a good impedance matching between the antenna and the chip. Experimental results demonstrate that the antenna has a suitable operating band about 914–939 MHz and also quite omnidirectional radiation pattern with appreciable gain. Moreover, the proposed compact tag antenna, capable of achieving a maximum readable range of about 5.6 m with an EIRP equal to 4 W, is well suited for RFID applications. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2770–2772, 2010; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25596
Compact dual‐band bandpass filter based on stepped impedance resonators and T‐shaped line
Authors: Feng Wenjie , Xue Quan , Che Wenquan
Published: October 2011

A compact dual‐band bandpass filter (BPF) realized with stepped impedance resonators (SIR) and T‐shaped line is proposed in this article. By appropriately selecting the impedance ratio of the SIR, a passband around at 5.4 GHz can be achieved by the second harmonic frequency of the SIR. In addition, a T‐shaped line is used to replace the quarter‐wavelength line between the two SIRs, and another passband at 2.45 GHz is realized between the transmission zeros created by the central open stub of the T‐shaped line and the fundamental frequency of the SIR. Moreover, the transmission zeros created by the central open stub and SIR could also be used to improve the skirt selectivity of the proposed BPF. Good agreement can be observed between the measured and simulated results, demonstrating the validity of the design strategies. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2721–2724, 2010; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25599
An intrusion detection sensor based on coherent optical time domain reflector
Authors: Hong Xiaobin , Guo Hongxiang , Wu Jian , Xu Kun , Zuo Yong , Li Yan , Lin Jintong
Published: October 2011

A distributed fiber optic intrusion detection sensor is proposed, in which a nonbalanced Mach‐Zehnder interferometer is used as phase demodulator, and an optical time domain reflectometer is used as a position detector. The experimental results concluded that the positioning error of ±25m can be achieved along an 8.8‐km single mode fiber. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2746–2748, 2010; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25602
A novel multipassband filter using asymmetric radial stubs
Authors: Sun Xiaofeng , Tan Eng Leong
Published: October 2011

This article presents a novel multipassband filter using asymmetric radial stubs.Asymmetric radial stubs are formed from two single‐radial stubs in different dimensions. The transmission zeros of such asymmetric structure can be controlled by the respective radial stub. By using these asymmetric radial stubs, the transmission zeros of the filter are realized. The multipassband of this filter includes a low‐pass band up to 2.66 GHz and another passband from 5.6 to 6.4 GHz. This filter has the attractive advantage of sharp rejection in the stopband. A demonstration filter is designed, fabricated, and tested. The simulated and measured results are presented. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2819–2821, 2010; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25609
Ultra‐wideband monocycle generation by using electroabsorption modulator and polarization differentiation method
Authors: Cheng Wen , Ye Chenhui , Zhu Kun , Fu Hongyan , Chen Biao
Published: October 2011

A novel scheme of ultra‐wideband pulse generation is proposed and experimentally demonstrated. The scheme is based on polarization differentiation control in an electroabsorption modulator. The optical structure is simple. Ultra‐wideband monocycle pulses with a 10‐dB bandwidth of 8.0 GHz have been generated. This generation system has the potential for large bandwidth, low‐voltage operation. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2817–2819, 2010; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25610
Designing a very wide stopband microstrip bandpass filter with patterned ground plane
Authors: Tang Ching‐Wen , Hsu Yen‐Kuo
Published: October 2011

In this article, a microstrip bandpass filter with a very wide stopband is provided.Based on our previous published ultra‐wide stopband bandpass filter, this proposed filter can extend the stopband range by adopting the patterned ground plane. The full‐wave electromagnetic simulator IE3D is used, and the prototype of the bandpass filter is fabricated and measured. Comparisons of simulated results and experimental data are shown; moreover, good match validates the proposed filter. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2845–2847, 2010; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25611
Wide bandwidth, high‐gain slot‐loaded rectangular microstrip antennas
Authors: Maddani G. P. , Sameena N. M. , Mulgi S. N.
Published: October 2011

The effect of slot on patch and on ground plane of rectangular microstrip antenna for effective size reduction, wide bandwidth, and high gain has been presented. A 60.57% of virtual size reduction is achieved by taking ground plane same as that of patch on another similar substrate and by keeping 1‐mm air gap between them. Furthermore, 51% of bandwidth and 8.73 dB of gain are achieved by embedding group of slots on the patch, wide slot on the ground plane and by doubling the thickness of substrate. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2841–2845, 2010; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25612
Efficient high gain with low sidelobe level antenna structures using circular array of square parasitic patches on a superstrate layer
Authors: Gupta R. K. , Mukherjee J.
Published: October 2011

This article proposes efficient high gain with low sidelobe level (SLL) antenna structures using circular array of square parasitic patches (CASPPs) for wireless applications. The antenna structure consists of a microstrip antenna that feeds a CASPP fabricated on a low cost FR4 superstrate. The patches on superstrate are suspended in air at about λo/2. The structure with 19‐element CASPPs is designed, fabricated, and tested. The measured VSWR is <2 over 5.725–5.875 GHz frequency band. The antenna with a single square patch provides a gain of 12.6 dB; whereas, the antenna with 19‐element CASPPs provides a gain of 18.3 dB with 93.4% efficiency, SLL of −26.1 dB, and front to back lobe ratio of >20 dB. Antenna with CASPPs on finite ground requires 25% less ground plane size as compared to planar array. The proposed structure can be packaged inside an application platform. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2812–2817, 2010; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25613