bluuebunny/crossref_metadata_2025_split huggingface dataset:
Small‐size antenna for seven‐band WWAN/LTE mobile handset
Authors: Huang Hui‐Fen , Wu Jun‐Feng 
Published: March 2015

ABSTRACTIn this article, a small‐size seven‐band antenna covering GSM850/900/1800/1900/UMTS2100/LTE2300/2500 bands for wireless wide area network/long term evolution mobile handset is presented. The developed antenna only occupies a planar size of 15 × 25 mm2. The capacitive coupling feed is used to generate fundamental resonant λ/8 mode and high‐order λ/4 mode to reduce the size. Electromagnetic (EM) coupling between the radiation strips is used to widen the operation band. The antenna consists of a feed strip and two radiation strips (RS1, RS2). RS2 is in the same side of the ground. RS1 is in the other side of substrate. Two λ/8 modes (at 850 and 925 MHz) and two λ/4 modes (at 1850 and 2200 MHz) are generated by the capacitive feed. Strip RS1 contributes to 850 and 1850 MHz modes, and strip RS2 contributes to 925 and 2200 MHz modes. In the mean time, there exists EM coupling between the two radiation strips (RS1, RS2), then dual‐resonance mode at 845 and 925 MHz form a wide lower band covering GSM850/900, two high order resonant modes at 1850 and 2200 MHz form a wide upper band covering GSM1800/1900/UMTS2100/LTE2300/2500. Design mechanics is analyzed and main parameters are studied. The proposed antenna is fabricated, and the simulated and measured results agree well. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1029–1033, 2015
Metamaterials microstrip patch antenna for wireless communication RFID technology
Authors: Naoui Seif , Latrach Lassaad , Gharsallah Ali 
Published: March 2015

ABSTRACTThis article is specialized to highlight the method of miniaturization and improvement the patch antenna using the complementary metamaterial. This method is presented by two different techniques. The first technique is composed a structure of patch antenna integrated in its surface a cell of complementary split ring resonator. This resonator is placed at the middle of the radiating patch in parallel with the transmission line and with a variable angle of orientation. The objective is to find the ultimate angle where the best results are obtained on improving the characteristics of the considered antenna. This motif widespread at the traceability applications by wireless communication for RFID technology at the operation frequency 2.45 GHz. In the second technique, were integrated at the surface of antenna a homogeneous and periodic array of complementary split ring resonators using the same position and the supreme orientation found in early studies. The advantage of the latter technique is to indicate the effect of increasing the number of resonators on the performance patch antenna and show the specifications and characterization of each technique proportionally at the two interesting factors miniaturization and improvement. Our contribution is based on studies and empirical and theoretical tests often presented in this article. All simulation results were made by the CST Microwave Studio. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1060–1066, 2015
Compact CPW‐fed half‐ring‐shaped slot antenna for harmonic suppression applications
Authors: Yeo Junho , Lee Jong‐Ig 
Published: March 2015

ABSTRACTA compact half‐ring‐shaped (HRS) slot antenna fed by a coplanar waveguide (CPW) transmission line for harmonic suppression applications is presented. The antenna consists of an HRS slot and stepped impedance resonators (SIRs) symmetrically appended to the slot at both ends. Two SIRs are used to suppress the harmonics of the fundamental resonance frequency with an additional effect of size reduction. The optimized HRS slot antenna with SIRs operating at 2.45 GHz is fabricated on an FR4 substrate with dimensions of 30 mm by 30 mm, and its performance is compared to that of a conventional rectangular slot antenna. The slot length of the proposed harmonic‐suppressed slot antenna is reduced by 45% compared to a conventional rectangular slot antenna owing to the HRS slot and appended SIRs. Experiment results show that the proposed antenna has the desired impedance characteristic with a frequency band of 2.39–2.49 GHz for a voltage standing wave (VSWR) < 2, and a measured gain of 1.5 dBi at 2.45 GHz. In addition, the suppression of the second, third, and fourth harmonics are successfully demonstrated. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1102–1104, 2015
A frequency reconfigurable mimo antennas using RF tuning element for mobile handset
Authors: Lee Won‐Woo , Cho Yong‐Sang 
Published: March 2015

ABSTRACTIn this letter, we develop a frequency tunable multiple‐input multiple‐output antenna for handhelds to achieve both the wideband tunability at the frequency ranges of 704–960 MHz and low correlation properties over the tuning frequencies. The proposed antenna covers various long‐term evolution (LTE) service bands: Band 17 (704–746 MHz), Band 13 (746–787 MHz), Band 5 (824–894 MHz), and Band 8 (880–960 MHz). The proposed LTE antennas are based on a switch‐loaded antenna structure, with a resonance frequency that can be controlled by a logic circuit. The tuning technique for the LTE antenna uses a SP4T RF switch to match the impedances to realize the bands of interest. The proposed main antenna consists of an inverted‐F antenna (IFA), the LTE subantenna is loop antenna structure. The use of two different antenna types of IFA and loop antenna achieves high isolation. We show that the proposed antenna has envelop correlation coefficient value as low as 0.5 over the designed frequency tuning ranges. The proposed antenna was fabricated and tested for experimental verification. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1092–1096, 2015
Multimode wideband diplexer using open‐ and short‐ended stub‐loaded hairpin resonator
Authors: Wu Bian , Qiu Feng 
Published: March 2015

ABSTRACTA fourth‐order multimode wideband diplexer with high selectivity and compact size is presented in this article. The open‐ or short‐ended stub‐loaded hairpin resonator (SLHR) is utilized to split one resonant mode to even‐mode and odd‐mode. A pair of SLHRs splits the two modes to four modes and also introduces two transmission zeros for each channel due to the mixed coupling. Using two kinds of SLHRs at the two filtering channel, a compact multimode wideband diplexer with center frequencies at 2.1 GHz/2.5 GHz and fractional bandwidths of 10.5%/8.5% are designed and fabricated. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1096–1099, 2015
An asymmetric split ring resonator for refractive‐based‐sensor applications at terahertz frequencies
Authors: Wu Dong‐Wei , Chen Hang 
Published: March 2015

ABSTRACTWe have proposed a terahertz metamaterials resonator that consists of a pair of split ring resonators (SRRs) and can be utilized as a refractive‐based‐sensor. Supporting simulations indicate the resonant Q value is up to 90 and a refractive sensitivity of 61.7 GHz/RIU, figure of merit value of 10.74, correspondingly. Resonator sample of the “connected SRR” has been fabricated and measured using a terahertz time‐domain spectroscopy system, the transmission characteristics of which are consistent basically with the finite difference time domain simulations. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1132–1135, 2015
Study on pattern synthesis of conformal array using enhanced adaptive genetic algorithm
Authors: Seong Cheol‐Min , Park Dong‐Chul 
Published: March 2015

ABSTRACTInvestigations on an enhanced adaptive genetic algorithm (EAGA) for pattern synthesis of a conformal array are presented. The proposed algorithm uses the advantages of the adaptive genetic algorithm (AGA) and the invasive weed optimization so that it improves the searching ability and the convergence speed. Convergence characteristics of the EAGA are compared with those of the AGA. Also, the pattern synthesis performance of the EAGA is compared with that of the AGA. A 4 × 16 conformal array operating as a 1 × 16 array in the azimuth direction is fabricated and measured to demonstrate the proposed algorithm. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1173–1176, 2015
A fundamental OOK modulator for 340 GHz communication using 0.13 μm CMOS technology
Authors: Deng Xiao‐Dong , Li Yihu , Wu Wen , Xiong Yong‐Zhong 
Published: March 2015

ABSTRACTThis letter presents a 340 GHz fundamental on–off keying modulator using 0.13 μm CMOS technology. The proposed modulator topology is composed of a 90° hybrid coupler and two series loads formed by a series inductor and a MOSFET for 340 GHz on‐/off‐state switching. The measured results indicate that the insertion loss is ∼4.9 dB on average and the isolation is better than 13 dB from 330 to 347 GHz. A measured data rate of 2.5 Gb/s is demonstrated at the carrier frequency of 340 GHz. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1166–1168, 2015
A compact meta‐atom for dual band negative permittivity metamaterial
Authors: Sarkhel Abhishek , Mitra Debasis , Paul Sandip , Chaudhuri Sekhar Ranjan Bhadra 
Published: March 2015

ABSTRACTIn this letter, a compact design of electric meta‐atom has been proposed as a dual band negative permittivity metamaterial. Compared with the earlier work, the proposed dual band meta‐atom has a better coupling strength at both the resonances and it is also more compact. This dual band design utilizes the mechanism of the resonance coupling between a meander line loaded delta loop meta‐atom and a rectangular close ring meta‐atom. The proposed meta‐atom is designed and investigated by both simulation and experiment with good agreement. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1152–1156, 2015
Broadband slotted patch antennas with circular polarization
Authors: Chen Jhih‐Ming , Row Jeen‐Sheen 
Published: March 2015

ABSTRACTA design for circularly polarized (CP) patch antennas with broadband operation is described and studied. The design is based on a traditional cross slot antenna excited with a microstrip line through coupling. It is found that when the ground plane of the cross slot antenna, namely the slotted patch has a specific aspect ratio, the CP radiation with a 3‐dB‐axial‐ratio bandwidth of more than 30% can be generated. For such a slotted patch antenna, parametric analyses are performed to demonstrate how to achieve the broadband CP operation in a limited area. Simulated and measured results for the performances of the constructed prototype are also shown. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1140–1143, 2015
A miniaturized quad‐band bandstop filter with high selectivity based on shunt‐connected, T‐shaped stub‐loaded, stepped‐impedance resonators
Authors: Adhikari Kishor Kumar , Kim Nam Young 
Published: March 2015

ABSTRACTThis letter presents a microstrip quad‐band bandstop filter (QBBSF) with a miniaturized size and high selectivity. The structure of the proposed QBBSF consists of two‐folded, shunt‐connected trisection stepped‐impedance resonators (TSSIRs). One of these TSSIRs, which operates on the second and fourth central frequencies, has been embedded inside another TSSIR operating at the first and third central frequencies of the proposed QBBSF. Characterized by equivalent circuit analysis and full‐wave EM simulations, each TSSIR has been miniaturized by a T‐shaped stub load. The main advantage of the proposed QBBSF lies in its central frequencies, which can be adjusted conveniently within a wide range by varying parameters of TSSIRs, the positions, and dimensions of the stub loads. A protocol QBBSF with a compact size of 0.0115 λg2 operating at central frequencies of 1.90, 3.32, 5.77, and 6.75 GHz was designed, simulated, and fabricated to verify the proposed method. The measured minimum stop band return loss of 21.4 dB and maximum pass band insertion loss of 0.66 dB indicated the excellent in‐band and out of band selectivity of the proposed QBBSF. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1129–1132, 2015
Wideband fiber‐optic delay line with dynamic delay drift compensation
Authors: Qi Xiaoqiong , Xie Liang , Wang Hui 
Published: March 2015

ABSTRACTA wideband and high resolution fiber delay line system based on a self‐fabricated distributed‐feedback (DFB) laser is demonstrated in this article, where the delay time drift due to temperature variance is compensated using the extensibility of the standard single‐mode fiber (SMF). The DFB laser with the amplitude bandwidth of 18 GHz and the in‐band phase variance within 60° is applied as the optical source to provide wideband microwave signal delay. The temperature‐dependence delay variance is measured up to 42.8 ps/km/°C in SMF delay line. A compensation capability of 600 ps is reached with a fiber stretcher acted on a motor‐driven 300 m SMF. The proposed system not only provides delay drift compensation for the environmental‐sensitive systems, but also a feasible solution to realize continuously tuning of delay for stable systems. The tunable range of the microwave delay could be further extended using longer stretched fiber. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1219–1222, 2015
Design of differential wideband bandpass filters with miniaturized size based on dual‐mode defected ground structure
Authors: Li Lin , Yang J.‐X. , Bao Jia , Du J.‐J. 
Published: March 2015

ABSTRACTDual‐mode defected ground structure (DGS) is presented to construct differential wideband bandpass filter (WBPF) with very compact size. This proposed DGS is composed of an etched rectangular loop with a central zigzag tapered structure on the bottom surface. Based on this DGS, the filter exhibits adjustable dual‐mode resonant characteristics under differential mode (DM) operation and widebandstop filtering characteristics under common‐mode (CM) operation. To verify the design concept, one filter to cover the UWB lower‐band has been designed, fabricated, and measured. The fabricated differential WBPF demonstrates a DM 3 dB fractional bandwidth of 59% with lower passband insertion loss of 0.52 dB, wider CM suppression better than 10 dB from DC to 11.5 GHz, and very compact size of 0.08
, where λg is the guided wavelength at the center frequency of the DM passband. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1210–1213, 2015
Compact triple‐band bandpass filter using spilt ring resonator
Authors: Rathore Vaishali , Awasthi Seema , Biswas Animesh 
Published: March 2015

ABSTRACTFrequency transformation technique has been used for designing a six‐pole (3 × 2 pole) symmetrical triple‐band bandpass filter. Coupling matrix is obtained for filter specifications with 20‐dB return loss in the passbands, 500 MHz overall 3‐dB bandwidth, and 3‐GHz center frequency. Square split ring resonator (SRR) has been used for implementing the coupling matrix which provides miniaturization. Filter has been optimized using ADS circuit and ADS Momentum simulation for better results. Symmetrical triple‐band bandpass filter is fabricated and measured results show good agreement with ADS Momentum simulated response. Filter design using coupling matrix is less time consuming alternative when implemented using SRR as the range of coupling coefficients for particular bandwidth and center frequency can be calculated a prior and SRR aids in compact design and accurate tuning of the filter. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1222–1225, 2015
Reduced field of view imaging using a static second‐order gradient for functional MRI applications
Authors: Islam Haisam , Glover Gary H. 
Published: March 2015

PurposeImaging using reduced FOV excitation allows higher resolution or signal‐to‐noise ratio (SNR) per scan time but often requires long radiofrequency pulses. The goal of this study was to improve a recent reduced field of view (FOV) method that uses a second‐order shim gradient to decrease pulse length and evaluate its use in functional MRI (fMRI) applications.Theory and MethodsThe method, which was initially limited to excite thin disc‐shaped regions at the isocenter, was extended to excite thicker regions off the isocenter and produced accurate excitation profiles on a grid phantom. Visual stimulation fMRI scans were performed with full and reduced FOV. The resolution of the time series images and functional activation maps were assessed using the full‐width half‐maxima of the autocorrelation functions (FACFs) of the noise images and the activation map values, respectively.ResultsThe resolution was higher in the reduced FOV time series images (4.1% ± 3.7% FACF reduction, P < 0.02) and functional activation maps (3.1% ± 3.4% FACF reduction, P < 0.01), but the SNR was lower (by 26.5% ± 16.9%). However, for a few subjects, the targeted region could not be localized to the reduced FOV due to the low Z2 gradient strength.ConclusionThe results of this study suggest that the proposed method is feasible, though it would benefit from a stronger gradient coil. Magn Reson Med 75:817–822, 2016. © 2015 Wiley Periodicals, Inc.
Chinese Indentured Mine Labour and the Dangers Associated with Early 20th Century Deep‐level Mining on the Witwatersrand Gold Mines, South Africa
Authors: Meyer A. , Steyn M. 
Published: March 2015

AbstractTrauma analysis in archaeological human remains can aid our understanding of cultural practices, socio‐economic status, environmental and social conditions, and even aspects of a person's occupation. For this reason, fracture patterns and frequencies can be useful in making inferences about the environment people lived and worked in. This is especially true for the 20th century mining industry where unskilled migrant labourers were often subjected to harsh working and living conditions. In this study, the skeletal remains of 36 Chinese indentured mine labourers, who worked and died on the Witwatersrand mines, South Africa, during the period ad 1904–1910, were assessed for evidence of trauma. Historical information suggests that these indentured Chinese labourers were unfamiliar with the workings of deep‐level mines and as a result sustained many work‐related injuries. Analyses suggest low frequencies of ante‐mortem trauma. In the few instances where they occurred, these healed fractures most probably reflect injuries already sustained in China, some time before Chinese indentured employment on the Witwatersrand mines. A high frequency of traumatic lesions, specifically peri‐mortem fractures, however, suggests a drastic shift in their working environment attesting to the hazardous working conditions associated with deep‐level mining in the early 20th century. Copyright © 2015 John Wiley & Sons, Ltd.
Transforming Relations of Gender, Person, and Agency in Oceania
Authors: Morgain Rachel , Taylor John P. 
Published: March 2015

AbstractThis introduction contextualises the nine papers that make up the special issueGender and Person in Oceania. Gender and personhood represent core orienting concepts within Pacific anthropology, from the pioneering work ofMarilynStrathern'sGender of the Giftto more recent scholarly attention to the impact ofChristianity and modernity. The papers in this volume offer a comparative and critical perspective on long‐standing ideas of ‘relational’ and ‘individual’ personhood across multiple sites inOceania, highlighting several key insights, including the importance of situated and relational understandings of agency and the centrality of those ‘things’ typically seen as non‐agentive to the formation of personhood. Most importantly, while re‐establishing the inseparable articulation of personhood with gendered dynamics, the contributors to this volume also highlight the differential, transforming, and shifting nature of engendered personhood, revealed through close attention to local knowledge, conditions, and practices.
Braed Praes in Vanuatu: Both Gifts and Commodities?
Authors: Jolly Margaret 
Published: March 2015

AbstractThe debate about braed praes as either gift or commodity has a long and complex genealogy in foreign writings on Oceania, engaging anthropologists, Christian missionaries, policy‐makers, and feminists. Debates between ni‐Vanuatu have been equally protracted, passionate, and complicated, creating an echo chamber of resounding conversations. Such debates and political contests about bride price address deep questions about the value of a woman – as a person, a worker, sexual partner, and mother – and engage profound philosophical questions about the local traction of imported distinctions between subjects and objects, persons and things, and how indigenous categories have been transformed by the longue durée of Christian conversions and simultaneous processes of commoditisation, complicit and conflictual. How have these transformed the ‘value’ of woman as bride and the character and significance of braed praes? Can the entrenched binaries in such debates be eclipsed by seeing braed praes as both gift and commodity?
‘Starting with a Prayer’: Women, Faith, and Security inFiji
Authors: George Nicole 
Published: March 2015

AbstractScholars of global security have recently been captured by the idea that there is a link between ‘sex and world peace’. They argue that the security of states and the international system should be understood as conditional upon the social, economic, and political standing of women. Accordingly, they contend that societies and states that display chauvinistic and discriminatory sociocultural influences are more tolerant of high levels of gender disadvantage and violence towards women, and more likely to be marked by general levels of belligerence, violence, and insecurity. Ideologies of faith are identified as helping to fuel this scenario. Hence, proponents of the ‘sex and world peace’ thesis construct a strongly oppositional relationship between gender and faith on the one hand, and gender and security on the other. In this paper, I challenge the idea that efforts to build security, gendered or otherwise, are only effective if they are secularised. I draw on examples from thePacific Islands to defend my case. While I concede that faith can be a source of insecurity in many parts of the Pacific Islands region, and is often invoked in ways that legitimise violence, I also discuss important examples that illustrate where and how faith is a resource for the region's women peacebuilders who have resisted violence in interpersonal, intercommunal, and interregional contexts.