bluuebunny/crossref_metadata_2025_split huggingface dataset:
Elliptic high‐pass filters with stepped impedance resonators in coplanar waveguide technology
Authors: Durán‐Sindreu Miguel , Bonache Jordi , Martín Ferran 
Published: February 2012

AbstractUltra compact elliptic‐function high‐pass filters (HPFs) in coplanar waveguide (CPW) technology are presented.The required shunt‐connected series resonators of the elliptic‐function response are implemented by means of stepped impedance resonators (SIRs), etched in the back substrate side. The accurate circuit model of the filter, including parasitic effects, is presented and used for design purposes. An order‐3 prototype HPF with 0.1‐dB ripple and 3‐GHz cutoff frequency is designed and fabricated as proof‐of‐concept demonstrator. The measured filter response is in good agreement with the ideal elliptic‐function in the region of interest. Filter dimensions are as small as 0.092λg × 0.185λg, λg being the guided wavelength at the cutoff frequency. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1094–1097, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26692
An improved FDTD scheme with polarization piece‐linearity technique for biological tissue modeling
Authors: Wang Shenyun , Liu Shaobin 
Published: February 2012

AbstractThe finite difference time domain (FDTD) has been popular to characterize wave propagation in biological tissue, which permittivity is generally described by Cole‐Cole dispersive model.The FDTD scheme by using fractional derivative to time‐domain polarization equation results in a fast and computational efficient algorithm. The accuracy obtained is, however, not generally as good as thoes of z‐transform and auxiliary differential equation methods. In this article, polarization piece‐linearity and nonlinear optimization techniques are proposed and utilized on the polarization fractional derivative appoach, which improved the accuracy while retains the high speed and efficiency advantage. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:888–891, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26698
Printed dual ring loop antenna for wireless applications
Authors: Lee Hyeonjin , Jung Jinwoo , Lim Yeongseog 
Published: February 2012

AbstractA wideband printed dual ring loop antenna is presented for the 5.2/5.4/5.8 GHz wide local area network (WLAN) and intelligent transfer system (ITS) band applications. The proposed antenna consists of dual ring loops, which are radiating ring loop and modified ring loop by ground plane. This antenna is fed by a coplanar waveguide. This provides wideband performance and relatively good matching. Considering a return loss criterion of less than 10 dB, the antenna operates in frequency bands of 4.83–6.25 GHz. A parametric study has also been conducted by varying the spacing between the dual rings to analyze its effect on the resonant frequency. The operating frequency bands of the antenna are able to support WLAN (5.15–5.825 GHz) and ITS (5.75–6.25 GHz) bands. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1093–1097, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26701
A novel fast and effective methodology for CMOS monolithic microwave integrated circuit syntheses
Authors: Chen Chih‐Chiang , Sun Hai‐Tao , Cin Jhen‐Jie 
Published: February 2012

AbstractThis research has proposed a simple, fast, and effective methodology entitled equivalent‐circuit‐cascade model for complex and complicated monolithic microwave integrated circuits (MMICs) consisting of the periodical guiding structure.After compared with the actual measurements, this method has been well verified to feasibly and rapidly work out, analyze, simulate, and design for MMIC electric performance. The CMOS broadband Wilkinson power divider being taken for study instance, it can much more obviously reduce the time and memory capacity of MMIC circuit design and analysis for three‐dimensional EM full‐wave simulation. This effective methodology gets one thirty‐first of CPU time and one fifth of memory capacity reduction improvements relatively under one failure condition. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1053–1056, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26704
Analysis and design of compact wide tunable‐band antenna based on reactively loaded patch
Authors: Mahmoud Samir F. , Sheta A. F. , Alkanhal Majeed A. , Alhekail Z. 
Published: February 2012

AbstractA square patch antenna with a single varactor loading is introduced as a tunable antenna over a wideband. Simulations as well as measurements demonstrate that the resonant frequency of the dominant mode can be tuned to cover more than one octave. Probe‐strip feed is used to enhance antenna matching over the entire tunable band. Cavity mode analysis is applied to a simple model of antenna to predict the lowest resonant frequency for an arbitrary location of the varactor loading. Excellent agreement between computed, simulated, and experimental results is reported. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:884–888, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26713
A novel compact antenna enhanced with variable notches
Authors: Rezaeieh Sasan Ahdi , Abbak Mehmet 
Published: February 2012

AbstractA novel, compact, variable‐notch omnidirectional antenna is presented.The antenna has a compact size of 22.5 mm (0.3λ) × 22.5 mm (0.3λ) × 1 mm and made on cheap FR4 with relative permittivity of 4.4 and dielectric loss tangent of 0.02. It has a stable omnidirectional pattern all over its operating frequencies and a satisfactory gain. Antenna geometry consists of a T‐shape cut in the patch plane and an inverse T‐shape parasitic element. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:946–949, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26716
OPTOS communications: A high‐performance solution
Authors: Aragón V. , García Á. , Amaro R. , Martínez C. , Sarmiento F. , Cabo J. , Sempere M. 
Published: February 2012

AbstractNational Institute for Aerospace Technology is developing a new nanosatellite, OPTOS, based on standard CubeSat. The key objective of this project is to build up a reliable platform for future applications: R&D, telecommunications, space qualification of components, and so on. The communication subsystem plays a key role in system reliability. OPTOS incorporates a customized subsystem that is being thoroughly tested and will try to ensure the quality of the radio link. This subsystem operates in the frequency of 402 MHz and consists of a transceiver and four monopoles onboard the satellite, and a directional antenna together with diverse and reliable ground equipment. The detailed description of telemetry, tracking and command (TTC), ground station (GS) equipment and antennas is in Section 2, as the main part of this article. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:943–946, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26717
Thin‐film barium strontium titanate varactor tunable dual‐band quadrature hybrid coupler
Authors: Djoumessi Erick E. , Oh Jaeho , Delprat Sebastien , Mohammed Chaker , Wu Ke 
Published: February 2012

AbstractA thin‐film barium‐strontium‐titanate (BST) and a conventional silicon varactor tunable dual‐band quadrature hybrid couplers are characterized and compared in this article. Both structures are composed of four quarter‐wavelength sections at a frequency located between the two operating frequencies, and with two pairs of open‐ended stubs. Frequencies tuning make used of BST interdigital and silicon varactor diode capacitors connected at the open‐ended stubs. The characterized BST interdigital capacitor presents a capacitive‐tunability of 52% through an applied voltage of 0 to 25 V, while 82.5% is for the selected commercial silicon varactor diode. The silicon varactor‐tuned dual‐band coupler exhibits 45.9 and 5.2% center operation tuning frequency for the first and the second band, respectively, while 29.2 and 4.3% are achieved by the BST tunable coupler. With two‐tone nonlinear characterization test, the BST tunable coupler biased at 0 and 25 V presents a better IP3 of +25.45 and +35 dBm, respectively, while +11.5 and +34 dBm are obtained for the silicon varactor tunable coupler. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:858–867, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26719
Pareto‐optimal synthesis of microwave amplifier to design the noise‐constrained gain value
Authors: Cengiz Yavuz , Konar Eray 
Published: February 2012

AbstractIn this work, synthesis of microwave amplifier is put forward as a constrained vector optimization problem whose components are to meet the specific gain value constrained by the minimum noise over the available bandwidth. Nondominated solutions are acquired using the nondominated Sorting Genetic Algorithm‐II as a fast nondominated genetic sorting algorithm wherefore these synthesis objectives generally conflict with each other. Then, the Pareto frontiers are obtained using these trade‐off solution sets between the performance characterization of the device results in the triplet of gain GT, noise F, and input VSWR Vi and its source (ZS) and load (ZL). It can be concluded that the Pareto‐optimal synthesis procedure provides microwave amplifier with optimum performance. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1079–1084, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26724
Printed triple‐band rectangular ring monopole antenna with symmetrical L‐strips for WLAN/WiMAX applications
Authors: Li Xin , Hu Wei , Wang Ya Fang , Shi Xiao Wei , Gu Xin Tao 
Published: February 2012

AbstractA novel printed triple‐band rectangular ring monopole antenna with symmetrical L‐strips for wireless local area network (WLAN) and worldwide interoperability for microwave access (WiMAX) applications is presented. The antenna is simply composed of a rectangular ring monopole, a pair of symmetrical L‐strips, and a modified T‐shaped stub. By adjusting the positions and the lengths of these structures, three different current paths can be produced at different frequency bands, respectively. On the basis of this concept, a prototype of the triple‐band antenna has been designed, fabricated, and measured. The experimental results show that the antenna obtains the frequency bands of 2.36–2.93, 3.34–3.77, and 4.75–7.28 GHz with 10‐dB return loss, which can cover both the WLAN in 2.4/5.2/5.8‐GHz bands and the WiMAX in 2.5/3.5/5.5‐GHz bands. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1049–1052, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26733
Monopole slot antenna design for WLAN MIMO application
Authors: Chen Wen‐Shan , Lin Chi‐Huang , Lee Bau‐Yi , Hsu Wen‐Hsiu , Chang Fa‐Shian 
Published: February 2012

AbstractA monopole slot antenna with compact size designed at WLAN band (2.4–2.484 GHz) is proposed for multiple‐input multiple‐output application. By the concept of electromagnetic shield, the antenna module is formed by an open‐ended monopole slot surrounded by another open‐ended monopole slot on the ground plane. The two identical folded antenna modules located on the both side of the ground plane are separated by an isolated element for increasing isolation more than 17.8 dB within the operating band. To increase antenna's bandwidth, the two open‐ended monopole slot antennas with different lengths are printed to obtain two resonant modes, which are close at around 2.4 GHz. In addition, the proposed antenna occupies a small area of 10.5 × 20 mm2 and can be easily fabricated on an FR4 substrate that is a commonly used circuit board. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1103–1107, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26740
Generation of high power pulse of Bi‐EDF and octave spanning supercontinuum using highly nonlinear fiber
Authors: Ahmad H. , Awang N.A. , Latif A. A. , Harun S. W. 
Published: February 2012

AbstractA compact and stable system for the generation of a super‐continuum (SC) at the 1550 nm region is proposed and demonstrated. Mode‐locked pulses at a pulse‐width of 200 fs and a peak power of 2.2 kW are generated using the nonlinear polarization rotation technique in a short length of Bi‐EDF of about 48.2 cm. The generated pulses at a repetition rate of 41.6 MHz are then launched directly into a 100 m long highly non‐linear fiber, without requiring any amplification stages. The generated SC spectrum covers a range of 1200–1950 nm. The wavelength bandwidth of the SC is over 413.5 nm at the 3‐dB power level and the SC pulse width is about 90 fs. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:983–987, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26744
Ultra‐wideband (UWB) power divider based on signal interference techniques
Authors: Zhuge Chunlin , Song Kaijun , Fan Yong 
Published: February 2012

AbstractA novel ultra‐wideband (UWB) power divider based on signal interference techniques is presented. The short‐ended symmetrical coupled‐line and transversal transmission line are introduced at both output ports of the power divider. The proposed power divider is analysed with the even and odd mode approach. Simple design procedure and several equations can be applied to find the parameters of the device. A prototype power divider is designed and fabricated to demonstrate the performance of the UWB power divider structure. Experimental results show good performance in UWB passband. In addition, a stopband with over 20 dB attenuation is from 12.2 to 17.2 GHz. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1028–1030, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26745
The complex material properties of chalcopyrite and kesterite thin‐film solar cell absorbers tackled by synchrotron‐based analytics
Authors: Schorr Susan , Mainz Roland , Mönig Harry , Lauermann Iver , Bär Marcus 
Published: February 2012

ABSTRACTIn view of the complexity of compound semiconductor based thin‐film solar cells, which are comprised of a multitude of layers, interfaces, surfaces, elements, impurities, etc., it is crucial to characterize and understand the structural, chemical, and electronic properties of these components. Hence, this paper gives a review of our recent progress in the characterization of compound semiconductor thin films using synchrotron‐based characterization methods. It is demonstrated how different analytical techniques are extraordinarily powerful to reveal the material characteristics from many different perspectives, ultimately resulting in a comprehensive picture of these properties. Light will be shed on structural phase transitions, reactive thin‐film formation mechanisms, surface off‐stoichiometries, and the electronic structure of chalcopyrite and kesterite compound semiconductors. Copyright © 2012 John Wiley & Sons, Ltd.
Exciton confinement in narrow non‐polar InGaN/GaN quantum wells grown on r‐plane sapphire
Authors: Badcock T. J. , Kappers M. J. , Moram M. A. , Hao R. , Dawson P. , Humphreys C. J. 
Published: February 2012

AbstractWe have investigated the optical properties of a series of non‐polar InGaN/GaN single quantum wells (QWs) grown on r‐plane sapphire with QW widths ranging from 7 to 45 Å. The emission is attributed to recombination in regions of the QW intersected by basal plane stacking faults. For QW widths < 30 Å, the linewidth of both the photoluminescence (PL) spectrum and the QW exciton measured in PL excitation reduces with decreasing QW width, effects which are attributed to the increasing penetration of the exciton wavefunction into the GaN barriers. Furthermore, the associated increase in confinement energy is proposed to induce a delocalisation of the exciton within the plane of the QW/basal plane stacking fault (BSF), which results in an increased temperature sensitivity of the integrated emission intensity for QWs narrower than 22 Å.
Ultrafast coherent spectroscopy of a single self‐assembled quantum dot
Authors: Wolpert Christian , Dicken Christian , Wang Lijuan , Atkinson Paola , Rastelli Armando , Schmidt Oliver G. , Giessen Harald , Lippitz Markus 
Published: February 2012

AbstractThe controlled interaction of several quantum dots (QDs) mediated by plasmonic or photonic nanostructures promises interesting new functionality in the fields of quantum computing and telecommunication. Ultrafast laser pulses can be used to write and read out the state of the QD. We review ultrafast coherent spectroscopy of single QDs. The focus of this article is on the technique of transient reflection spectroscopy which can be applied to a broad range of samples and devices. It only requires optical access to a single quantum system next to a reflecting surface. We demonstrate the versatility of our approach by presenting several quantum optical studies such as Rabi oscillations, perturbed free induction decay, and quantum beats from an entangled excitonic state in weakly absorbing GaAs QDs. We expect this experimental method to make coherent experiments possible in elaborate devices where quantum emitters are interacting with a complex environment such as plasmonic waveguides or antennas.
Field trial results of planetary rover visual motion estimation in Mars analogue terrain
Authors: Bakambu Joseph Nsasi , Langley Chris , Pushpanathan Giri , MacLean W. James , Mukherji Raja , Dupuis Erick 
Published: February 2012

AbstractThis paper presents the Mojave Desert field test results of planetary rover visual motion estimation (VME) developed under the “Autonomous, Intelligent, and Robust Guidance, Navigation, and Control for Planetary Rovers (AIR‐GNC)” project. Three VME schemes are compared in realistic conditions. The main innovations of this project include the use of different features from stereo‐pair images as visual landmarks and the use of vision‐based feedback to close the path‐tracking loop. The multiweek field campaign, conducted on relevant Mars analogue terrains, under dramatically changing lighting and weather conditions, shows good localization accuracy on the average. Moreover, the MDA‐developed inertial measurement unit (IMU)‐corrected odometry was reliable and had good accuracy at all test locations, including loose sand dunes. These results are based on data collected during 7.3 km of traverse, including both fully autonomous and joystick‐driven runs. © 2012 Wiley Periodicals, Inc.
Views of the frontiers in climate change adaptation economics
Authors: Downing Thomas E. 
Published: February 2012

AbstractThe shift from framing climate change adaptation as vulnerability–impacts to adaptation pathways is also a shift from a predict‐and‐provide approaches to understanding dynamic processes. Studies of the economics of adaptation relying only on the comparative statics of reference and climate impacts scenarios ignore the more challenging frontier of representing decision processes and uncertainty. The logic of the shift to dynamic‐pathway approaches is widely accepted in principal. Effective analytical tools are only beginning to appear. Further case studies are required to explore the matrix of uncertainty in future climate conditions against the range of metrics for valuing impacts in decision processes. WIREs Clim Change 2012, 3:161–170. doi: 10.1002/wcc.157This article is categorized under:

Climate Economics > Aggregation Techniques for Impacts and Mitigation Costs
Estimating sika deer abundance using camera surveys
Authors: Dougherty Sean Q. , Bowman Jacob L. 
Published: February 2012

AbstractCameras have been used throughout the world to estimate wildlife abundance and occupancy. Abundance estimates generated by camera surveys tend to be less invasive, less costly, and more accurate than other means in certain situations. We sought to expand and test the effectiveness of camera surveys on sika deer in Maryland. In 2008, we setup surveys with a 7‐day pre‐bait period followed by a 7‐day active camera survey with 15 cameras. In 2009, we ran the cameras for the entire 14‐day survey and moved cameras after each survey to determine if biases occur when using the same camera sites. During both years and all surveys, camera density was approximately 1‐camera/65‐ha. The abundance estimates were similar between years and estimators. In 2009, increasing photo intervals from 1‐min to 5‐ and 10‐min intervals reduced the number of pictures by 66 and 81%, respectively, while providing similar abundance estimates. We calculated the daily detection probabilities for all identifiable deer and we used radio‐collared males that occurred within 2 km of the survey grid to assist in determining the optimum survey length. Detection probability did not vary between surveys in the same year, but varied between 2008 and 2009, most likely due to unlimited bait being available during 2008 surveys. Camera surveys have proven to be an accurate and cost effective means of estimating wildlife abundance and can be used successfully to determine sika deer abundance.
Challenges in studies on flowering time: interfaces between phenological research and the molecular network of flowering genes
Authors: Kobayashi Masaki J. , Shimizu Kentaro K. 
Published: February 2012

AbstractFlowering time is a well‐studied subject in ecology, evolution and molecular biology. Long‐term phenological studies have shown relationships between flowering time and environmental and endogenous factors in many species. In contrast, molecular studies using model plants have revealed a complex regulatory network of flowering. We propose that flowering would be a model trait for the integrated study of ecology, evolution and molecular biology. We introduce briefly the flowering regulatory pathways of Arabidopsis thaliana, followed by molecular techniques such as transgenic manipulation, quantitative real‐time PCR and detection of differentially expressed genes that could facilitate the study of ‘nonmodel’ species of ecological interest but with little available genome information. Application of the flowering gene network to wild species will be illustrated by two examples: modeling and prediction of the expression of flowering genes in Arabidopsis halleri, and the latitudinal cline of bud set and cessation in Populus. Finally, we discuss the challenges in integrating knowledge of the regulatory network on flowering into ecologically unique flowering phenomena such as synchronous intermittent mass flowering—the topic of this special issue.