bluuebunny/crossref_metadata_2025_split huggingface dataset:
Multiwavelength tunable ring fiber laser operating at 1.9 μm
Authors: Aihui Gong , Wanzhuo Ma , Tianshu Wang , Qingsong Jia , Peng Zhang , Chunming Wan 
Published: December 2014

ABSTRACTA multiwavelength tunable fiber laser operating at 1.9 µm is demonstrated. A 4 m long Tm‐doped single‐mode fiber is pumped by a 1.57 µm fiber laser. A Sagnac fiber loop is used in the fiber laser cavity as a tunable filter, and the fiber loop consists of a 3‐dB coupler, a polarization controller (PC), and a segment of polarization‐maintaining fiber. Adjusting the PC state and pump power, multiwavelength laser with wavelength spacing of 2.5 nm 1895–1915 nm is observed. The number of output wavelength can be tuned precisely from one to four by adjusting the PC state. The 3‐dB linewidth and side‐mode suppression ratio are 0.045 nm and 45 dB, respectively. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:401–403, 2015
Uniform magnetic field by changing the current distribution on the planar coil for displacement‐insensitive wireless power transfer/near field communication
Authors: Shen Laiwei , Tang Wanchun , Xiang Huiling , Zhuang Wei 
Published: December 2014

ABSTRACTIn either inductive or strongly coupled magnetic resonance type wireless power transfer, the uniformity of magnetic field distribution near the transmitting coil is urgent needed as it would affect the stability of transfer efficiency when the receiving coil is moving. In this article, we proposed a new coil structure to achieve uniform magnetic field based on the relationship between the magnetic field distribution and current distribution of a coil structure. The coil is constructed of three or more spiral coils in series, where each spiral coil has a different current through a novel winding structure. The design procedure is presented, and the improved performance is verified by experiment. Compared with previous literatures, this proposed coil can generate a better uniform magnetic field distribution. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:424–427, 2015
A reconfigurable mobile antenna for multiband operation using PIN‐diode
Authors: Hwang Sun‐Gook , Yoon Cheol , Yoon In Seop , Chares Ludovic , Park Chan Seop , Kim Woo‐Su , Lee Hwa‐Choon , Park Hyo‐Dal 
Published: December 2014

ABSTRACTThis article proposes a mobile embedded antenna having tunable capacitance, and the validity of the proposed solution has been proven through its design, fabrication, and measurement. The antenna can be applied to long‐term evolution (LTE) and DCS/PCS/wideband code division multiple access bands that are currently being used. The 4G mobile service requires antennas to expand its bandwidth so that it can include the LTE band and other service bands. However, it is difficult to obtain the low‐band frequency due to the limited space for antennas in terminals. The proposed antenna with a PIN‐diode was added to a basic planar inverted‐F antenna structure to satisfy the intended bandwidth through the ON/OFF characteristics of the PIN‐diode. To meet this requirement, a PIN‐diode (MA4P274–1279T) manufactured by MACOM, was used to make the operation frequency of the low‐band tunable. The antenna was fabricated and then measured using the optimized parameters, and the results have been compared with the simulated results. The antenna satisfied the requirements for operation frequency and performance for both low‐band and high‐band frequencies. The measured performance of the antenna fabricated with the optimized parameters was analyzed and compared with the simulation results. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:406–409, 2015
A W‐band power detector RFIC design in 0.13 μm SiGe BiCMOS process
Authors: Jonsson Rolf , Reyaz Shakila Bint , Malmqvist Robert , Kaynak Mehmet 
Published: December 2014

ABSTRACTThis article presents the results of a wideband power detector radio frequency integrated circuit design intended for W‐band passive imaging sensors. The power detector was fabricated in a 0.13 µm SiGe BiCMOS process technology with 300 GHz/500 GHz fT/fmax. The experimental results show broadband RF properties such as a responsivity of 40–60 kV/W and a noise equivalent power (NEP) of 0.3–0.4 pW/Hz1/2 at 70–95 GHz, respectively (the DC power consumption is 225 µW). To the authors' best knowledge, the SiGe detector design reports the widest s11 −10 dB bandwidth (s11 ≤ −10 dB at 79–102 GHz) among silicon based W‐band power detectors and is competitive with InP‐based W‐band detectors in terms of a higher responsivity and similar NEP. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:414–417, 2015
Beam steering patch antenna using reactive loading and Yagi‐antenna concept
Authors: Nguyen Duy‐Thong , Siragusa Romain , Tedjini Smail 
Published: December 2014

ABSTRACTThis letter reports a technique to create beam‐steering antennas using reactive loading and passive patches. In this antenna configuration, the center patch is fed by a microstrip line and the two neighbor patches are excited through the mutual coupling from the active antenna. These two patches are loaded with a varactor diode and present a phase shift that depends on varactor capacitance. The impact of the mutual coupling on the impedance matching is investigated through a numerical calculation that combines 3D full‐wave simulation and network analysis formulas. The steering capability is enhanced by adding “director” passive patches as in the Yagi antenna principle. A prototype is designed, fabricated, and measured at UHF frequency (865–868 MHz) and shows a good agreement with the simulation. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:417–421, 2015
A compact ultra‐wideband quadrature hybrid based on coupled‐line phase shifter and power divider
Authors: Liu Qiang , Liu Yuanan 
Published: December 2014

ABSTRACTA compact ultra‐wideband three‐port quadrature hybrid based on a coupled‐line 90° phase shifter and a Wilkinson power divider is proposed. The circuit configuration and theoretical calculation are presented. Using a short‐circuited stub and coupled lines, the design not only exhibits considerably large bandwidths but also provides compact structure. A microstrip prototype at 1.68 GHz is simulated, implemented, and measured for verification. The measured performance is consistent with the simulated result. The prototype achieves measured bandwidths of 118% for output power imbalance less than ±0.5 dB, and the return loss of input port and isolation between output ports are better than 11 dB in the band. What is more, the bandwidth for output ports phase deviation of 90° ± 4.5° is large than 137%. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:432–434, 2015
Self‐phasing of quadrifilar helix antenna by relative axial displacement of bifilars
Authors: Masoud Qureshi Adil , Amin Muhammad , Ali Shah Waqar 
Published: December 2014

ABSTRACTSelf‐phasing can be achieved in a quadrifilar helix antenna (QHA) by displacing one of the bifilars along the axis of the helix, yielding a circularly polarized cardioid shaped pattern. Impedance bandwidth of 10% (2105–2345 MHz) has been achieved with Front to back ratio greater than 10 dB. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:430–432, 2015
Analysis and design of implantable Z‐monopole antennas at 2.45 Ghz ISM band for biomedical applications
Authors: Ashok Kumar Srinivasan , Shanmuganantham T. 
Published: December 2014

ABSTRACTA novel coplanar waveguide fed z‐monopole implantable antenna has proposed for ISM band biomedical applications. The antenna operates at the resonant frequency of 2450 MHz, wideband communication for high‐data rate implantable biomedical application. The size of the antenna is 38.675 mm3 (7, 8.5, and 0.65 mm). To make the designed antenna suitable for implantation, it is printed on biocompatible Al2O3 ceramic substrate. The proposed antenna was simulated and measured by a phantom liquid and imitating the electrical properties of the human muscle tissue. A study of the understanding of the antenna performance as a function of its dielectric parameters of the environment in which it is immersed was performed. Simulations in various slot widths state demonstrate that the antenna covers the complete ISM band. The specific absorption rate distribution induced by the implantable antenna inside a tissue‐mimicking solution is evaluated. The proposed antenna shows the lower return loss, good impedance matching, and high gain compared to other implantable antennas. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:468–473, 2015
A low profile tri‐band diversity antenna for WLAN/WiMAX/HIPERLAN applications with high isolation
Authors: Singh Hari S. , Pandey Gaurav K. , Bharti Pradutt K. , Meshram Manoj K. 
Published: December 2014

ABSTRACTA low profile tri‐band compact multiple input multiple output (MIMO) antenna operating at 2.4 GHz band (2.4−2.485 GHz), 3.4 GHz band (3.25−3.5 GHz), and 5.5 GHz band (5.15−5.85 GHz) for WLAN, WiMAX, and HIPERLAN band is presented, respectively. The proposed MIMO antenna consists of two planar inverted‐F antenna elements located at the top two corners of PCB. Each element dimension is reduced substantially by using a meandered line and folded patch structure with two vertical parasitic strips so that it takes a small volume of 9 × 8.8 × 5.4 mm3. Two nonradiating folded shorting strips are connected between each antenna element and ground plane of PCB to enhance the port isolation. The S‐parameters, mean effective gain, envelope correlation coefficient, effective diversity gain, total efficiency, and peak realized gain are studied. The optimized structure is fabricated and measured. Good agreement is obtained between the simulated and measured results. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:452–457, 2015
A semicircular shaped super wideband patch antenna with high bandwidth dimension ratio
Authors: Samsuzzaman M. , Islam M. T. 
Published: December 2014

ABSTRACTIn this article, a novel semicircular shaped mono pole antenna has been investigated for super wideband (SWB) applications with high bandwidth dimension ratio (BDR). The proposed antenna consists of semicircular shape patches and partial trapezoid ground plane. A tapered feed line is precisely connected to semicircle shaped patch, which provides extremely wide impedance bandwidth greater than ultra‐wideband (UWB). The gap between the trapezoid ground plane and semicircular patch also plays a vital role to achieve wide impedance bandwidth. Studies of the antenna are performed using computer simulation tool HFSS. Prototype of the antenna is used for validation and verification for simulation results. Measurements to determine that the proposed printed antenna has an extremely wide impedance bandwidth (VSWR 2:1) from 1.30 to 20 GHz (175.58%) with a ratio bandwidth of 15.38:1 and BDR of 4261. 007 which is the highest among literature review. Furthermore, the proposed antenna also demonstrated a wide 14‐dB bandwidth from 4.90 to 10.95 GHz, which is suitable for UWB outdoor propagation. The simple construction, much impedance bandwidth, average peak gain (4.18 dBi), and stable omnidirectional radiation pattern are a good deal sounder than the recently reported SWB antennas which make it appropriate for many wireless communication systems such as L band, WCDMA, ISM, Wi‐Fi, LTE 2600, Bluetooth, WLAN, WiMAX, UWB, and MVDDS. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:445–452, 2015
The impact of different light sources on the optical correlator based on fiber dispersion
Authors: Zhongwei Tan , Ka Li , Fengjie Qin 
Published: December 2014

ABSTRACTWe investigate the impact of different light sources on the optical correlator based on fiber dispersion that can implement a time‐spectrum convolution. Simulation and experiment show that the performance of optical correlator degenerates with the increase of optical source's bandwidth. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:441–445, 2015
Three‐dimensional RF SoP technologies: LTCC versus LCP
Authors: Arabi Eyad , Shamim Atif 
Published: December 2014

ABSTRACTThe system on package (SoP) is an emerging platform, introduced to provide enhanced functionality, and immense miniaturization through vertically integrated passive components in a multilayer process. This way the package is not a mere holder or cover but is a functional part of the system. The leading multilayer packaging technologies for SoP designs: low temperature co‐fired ceramic (LTCC) and liquid crystal polymer (LCP) are compared in this work for the first time. Passive components and filters have been implemented in both technologies to show the advantages of the three‐dimensional nature of these technologies. The comparison results show that parallel plate capacitors implemented in the ultra‐thin LCP provides the highest capacitance density. For spiral inductors, conversely, LTCC inductors have the highest inductances while LCP inductors offer the highest self‐resonant frequencies and the highest quality factors (Q). In a circuit level, simulated and measured results of a bandpass filter at 1.5 GHz show that both LCP and LTCC can provide similar performances with an incredible size reduction for the case of ultra‐thin LCP. Also, the thin LCP filter exhibits a large degree of mechanical flexibility which makes this technology suitable for future flexible modules. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:434–441, 2015
Small‐size two‐branch monopole antenna with integrated wideband matching network for LTE tablet computer
Authors: Wong Kin‐Lu , Hsu Shan‐Ni 
Published: December 2014

ABSTRACTA simple two‐branch monopole antenna with an integrated wideband matching network to achieve the LTE dual‐wideband operation (698–960/1710–2690 MHz) with a small occupied volume (10 × 30 × 3 mm3) in the tablet computer is presented. The two‐branch monopole contributes to one resonant mode in the LTE low band and one resonant mode in the LTE high band. With the aid of the wideband matching network, the bandwidths of the two resonant modes can both be widened to cover the LTE dual‐wideband operation. In addition, the matching network requires no additional board space on the system circuit board of the tablet computer and is disposed inside the ground clearance region occupied by the antenna. This makes it attractive for practical applications. Working principle of the wideband matching network on achieving the antenna's dual‐wideband operation is described in this study. The antenna is also fabricated and tested. Experimental results are presented and discussed. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:507–513, 2015
Large printed loop antenna dimension reduction through layered substrates
Authors: Souza Jorge A. M. , Mosso Marbey M. , Magri Vanessa P. R. 
Published: December 2014

ABSTRACTThis article presents a new way to use multilayered substrates configurations aiming to, instead to optimize the gain of a printed loop antenna, to obtain a significant reduction of the antenna dimension. A circular loop antenna transformed in an octagonal shaped loop antenna is conceived, simulated, realized, and measured. A new antenna inside a multilayer configuration presenting a dimension reduction of 61% is obtained. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:504–507, 2015
A dual‐band branch line coupler based on Pi‐shaped coupled lines
Authors: Katakam Sri , Ren Han , Shao Jin , Zhou Mi , Arigong Bayaner , Ding Jun , Zhang Hualiang 
Published: December 2014

ABSTRACTThis article presents a coupler using Pi‐shaped coupled lines for dual‐band operations. In this design, two open circuited stubs are tapped at both ends of a coupled line structure to realize the 90° phase changes at two frequencies. The designed structure is used in place of a conventional quarter wavelength transmission line for dual‐band application. For verification, a 3‐dB branch line coupler with operating frequencies of 0.95 and 1.52 GHz is designed. The simulated and measured results are in good agreement with each other. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:501–504, 2015
Reconfigurable notched wideband antenna using EBG structure
Authors: Majid Huda A. , Kamal Mohamad , Rahim A. , Hamid Mohamad R. , Murad Norasniza A. , Asmawati Samsuri Nor , Fairus Mohd Yusof Mohd , Ayop Osman 
Published: December 2014

ABSTRACTIn this article, a wideband monopole antenna with band notched reconfigurability is proposed. The antenna consists of a wideband monopole antenna, incorporated with reconfigurable electromagnetic bandgap (EBG) structures. Six EBG structures with different band notched frequency are used to achieve six band notched reconfigurations. The EBG structures are placed underneath the feed line of the antenna. A switch is placed at each EBG structure, and by controlling the state of the switch, the band notched operation of the EBG can be activated or deactivated. The proposed antenna is capable to provide useful features for the notched band UWB communication system. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:497–501, 2015
Broadband high‐efficiency power amplifier with harmonic suppression based on load‐pull technique
Authors: Wang Zhenyang , Liu Falin , Wang Haoyu 
Published: December 2014

ABSTRACTIn this letter, a novel design method for broadband and efficient power amplifier (PA) is proposed and a broadband PA with a compact matching topology is designed and fabricated to verify the validity of the method. In the method, specific attention has been paid to harmonic suppression to enhance efficiency and an appropriate design space of the fundamental and harmonic impedances, based on load‐pull technique which actually takes into account of the influences of the parasitics, is found to alleviate the difficulty of designing broadband matching network. Then a compact matching network topology is proposed to lead the fundamental and second harmonic impedances to the design space on the Smith chart over a wide bandwidth, simultaneously. The fabricated PA exhibits greater than 63% power added efficiency from 1.5 to 2.5 GHz (50% relative bandwidth), and 40.5–42 dBm saturated output powers. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:481–485, 2015
Wide‐field circular SAR imaging: An empirical assessment of layover effects
Authors: Demirci Sevket , Yigit Enes , Ozdemir Caner 
Published: December 2014

ABSTRACTIn circular synthetic aperture radar (CSAR), targets are usually scanned over the complete azimuthal aperture of 360°. A major challenge inhibiting successful CSAR image production is encountered in two‐dimensional imaging of relatively large scenes (i.e. wide‐field scenarios). For such cases, the spatially variant radar signature gives rises to image degradations known as layover effects. In this paper, the imaging results for hypothetical and real complex targets using their CSAR data at C band are demonstrated to characterize these effects. In real experiments, a ground‐based, outdoor CSAR system is exploited thanks to the circular balcony of a building that provides 270° view of targets. A spherical back‐projection algorithm is used to focus near‐field data and the reconstructed images are also cleaned out from clutter to more easily visualize the layover artifacts. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:489–497, 2015
Compact and high‐selectivity microstrip bandpass filter using quad‐mode resonator
Authors: Chen Jianzhong , Sheng Jie , Gao Ni , Zhang Anxue 
Published: December 2014

ABSTRACTIn this letter, a compact high‐selectivity microstrip bandpass filter utilizing a novel quad‐mode resonator is presented. The proposed quad‐mode resonator can be treated as the combination of a short‐circuited stub loaded open‐ended resonator and a short‐circuited stub loaded short‐ended resonator. It results to generate four resonatant modes closely to each other, while each modal resonant frequency can be freely and easily controlled in a wide range as well. Due to the inherent transmission zero produced by the feed lines, the passband selectivity gets improved, which results good out‐of‐band rejection. Finally, a quad‐mode filter example with miniaturized size, wide fractional bandwidth, and high selectivity is designed and fabricated. Good agreement between experiment and simulation is observed. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:478–481, 2015
Erratum for: Raman amplified access networks with pump signal recycling for electrical power conversion
Authors: Andre P.S. , Lima M. J. N. , Rocha A. M. , Fernandes N. , Granada M. , Almeida T. , Cang Jin , Lan Rao , Xiang‐Jun Xin 
Published: December 2014

ABSTRACTNowadays, the structure of the passive optical networks is evolving, to keep the network survivability, the powering of some elements in this kind of networks is a key issue. In this work we propose the recycling of the Raman pump remaining optical power at the receiver to be converted to electrical power. With a 24 dBm optical pump signal a 8 dB on/off gain over 25 km of single mode optical fiber was achieved. Also, the recycling of the pump signal generated 18.1 mW of electrical power at the receiver. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:116–119, 2012
BUILDING ENFORCEMENT CAPACITY: EVIDENCE FROM THE MEXICAN CIVIL SERVICE REFORM
Authors: Nieto Morales Fernando , Heyse Liesbet , del Carmen Pardo María , Wittek Rafael 
Published: December 2014

SUMMARYBuilding enforcement capacity, that is, attaining and sustaining control in order to implement changes, is crucial for the success of public management reforms. However, this aspect of public management reform does not receive much theoretical or empirical attention. This paper analyzes the process of building enforcement capacity for the case of the Mexican Professional Civil Service reform. Although this reform experienced several complications (e.g., limited support, resources, and credibility), important goals were attained and some control was achieved. We study how officials attained control over implementation through the adaptive management of combinations of different types of control strategies (regulatory, normative, and procedural). The case study, focused on the analysis of in‐depth interviews with the highest officials involved in the implementation of this reform, finds evidence for three combinations of strategies next to a general pattern characterized by a trade‐off between compliance and coordination. This trade‐off shows that the process of building enforcement capacity may affect the goals of the reform, deviating from lawmakers' original intentions Copyright © 2014 John Wiley & Sons, Ltd.
Mapping parameters across system boundaries: parameterized model reduction with low rank variability in dynamics
Authors: Baur Ulrike , Beattie Christopher , Benner Peter 
Published: December 2014

AbstractLinear dynamical systems with an affine parameter dependence producing low‐rank variation in the state matrix can be recast as a nonparameterized system operating in parallel with a parameterized feed forward term operating under output constraints. This mapping permits the application of standard (nonparametric) model reduction strategies to solve parameterized problems. We demonstrate the approach on a parameterized vibration problem using
${\cal H}_2$
optimal tangential interpolation. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)