bluuebunny/crossref_metadata_2025_split huggingface dataset:
A method for antenna gain measurements in nonanechoic sites
Authors: Tamas Razvan D. , Deacu Daniela , Vasile Gabriel , Ioana Cornel 
Published: April 2014

ABSTRACTA measuring technique for antenna gain is presented, based on averaging a normalized transfer function over a distance range. Criteria for setting the distance range are drawn by investigating the effects of reflection and diffraction. Our method is compared to the time‐gating method by measuring two low‐gain, quasi nondirectional antennas. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1553–1557, 2014
MIMO application UWB antenna doublet incorporating a sinusoidal decoupling structure
Authors: Bilal Muhammad , Saleem Rashid , Shafique Muhammad F. , Khan Hassan A. 
Published: April 2014

ABSTRACTIn this article, a miniaturized multiple input and multiple output antenna doublet is proposed for the ultrawideband communication. Two semielliptical antenna elements having semicircular parasitic patches/defected ground planes, sine‐curve based meander‐line parasitic structures, and smoothly tapered feed lines are proposed in this article. Moreover, a sine‐curve based nested T‐shaped decoupling structure is used to achieve a decoupling/isolation of at least 20 dB over most of the frequency band. More importantly, the proposed design has a compact size of 30 × 50.5 mm2. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1547–1553, 2014
Design of a planar wideband patch antenna for UHF RFID tag
Authors: Bashri Mohd Saiful Riza , Ibrahimy Muhammad Ibn , Motakabber S. M. A. 
Published: April 2014

ABSTRACTIn this article, a planar wideband microstrip patch antenna for ultrahigh frequency (UHF) radio identification (RFID) tag is presented. By incorporating two resonating C‐shape patches, two resonances are excited close to each other to create wide impedance bandwidth to cover the entire operating frequency of UHF RFID system between 860 and 960 MHz for universal metal mountable tag. For complex impedance matching between the antenna input terminal and the referenced microchip whose impedance is Zchip = (31 − j212) Ω, a small rectangular loop feed structure was utilized where both of the resonating patches are magnetically coupled. The antenna design and simulation were carried out using finite element method based software, Ansoft HFSS v13. The simulated and measured radiation patterns at operating frequency of 915 MHz are in good agreement. The simulated and measured impedance bandwidth (Return Loss ≥ 3 dB) of 159 and 155 MHz were obtained that are well above the required 100 MHz bandwidth. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1579–1584, 2014
Compact balanced UWB bandpass filter with one narrow notched band
Authors: Wei Feng , Jay Guo Y. , Shi Xiao Wei 
Published: April 2014

ABSTRACTA compact balanced ultra‐wideband bandpass filter (BPF) with one sharply notched band is presented in this article. The proposed BPF based on microstrip‐to‐slotline transition obtains favorable uniform differential‐mode response and good common‐mode suppression. Moreover, one narrow notched band with a 3 dB bandwidth of 6.8% is realized by introducing one coupled half‐wavelength resonator. The fabricated filter has a more than 25% size reduction compared to the designs reported in open literature. The predicted results are compared with measured ones and good agreement is achieved. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1626–1629, 2014
Frequency tuning and miniaturizations of a bandwidth enhanced rectangular microstrip antenna
Authors: Chakraborty Ujjal , Chowdhury Santosh K. , Bhattacharjee Anup K. 
Published: April 2014

ABSTRACTThe effect of a rectangular ground slot (RGS) is investigated in a small‐sized microstrip antenna embedded with two rectangular and one half‐U open ended slots. It is observed that the resonance frequency of the proposed antenna can be tuned from 6.096 GHz down to 3.51 GHz by changing the length parameter of the RGS. The maximum impedance bandwidth is obtained about 16.02% for the size reduction of 42.44% and maximum size reduction is 81.48% for the impedance bandwidth of 5.24%. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1600–1603, 2014
Compact quad‐band BPF based on stub loaded double‐ring resonator
Authors: Wei Feng , Wei Shi Xiao 
Published: April 2014

ABSTRACTA compact quad‐band band‐pass filter (BPF) based on a single stub loaded double‐ring resonator (SL‐DRR) is presented in this article. The proposed SL‐DRR, which can introduce four narrow passbands simultaneously, is investigated using even/odd mode analysis. As an example, a BPF centered at 1.57, 2.8, 5.2, and 5.9 GHz is designed and it achieves a more than 45% size reduction compared to the designs reported in open literature. Theoretical and simulated results are presented, which are in good agreement with the measured ones. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1633–1635, 2014
A new compact quad‐band bandpass filter using quad‐mode stub loaded resonator
Authors: Weng Min‐Hang , Ye Chang‐Sin , Su Yan‐Kuin , Lan Siang‐Wen 
Published: April 2014

ABSTRACTA new compact quad‐band microstrip bandpass filter designed using a quad‐mode stub‐loaded resonator (SLR) is proposed. The equivalent circuit of the SLR consists of one even mode and two odd resonant modes, used to create passbands operated at 1.8, 2.4, 3.5, and 5.2 GHz, corresponding to global system for mobile communications, wireless local area networks, and worldwide interoperability for microwave access applications. The filter is compact in size because only two sets of resonator are used by means of the quad‐mode behaviors. Furthermore, 0° feed structures is used to set at least one transmission zero on each side of each passband, resulting in high skirt selectivity. Experimental results show good agreement with the simulated results. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1630–1632, 2014
Optimum design of Wpt relay system by controlling capacitance
Authors: Kim Ju‐Hui , Park Byung‐Chul , Lee Jeong‐Hae 
Published: April 2014

ABSTRACTThis article presents an optimum design method of a wireless power transfer (WPT) relay system. Magnetic couplings between nonadjacent resonators cause a frequency shifting of maximum efficiency in a WPT relay system. Thus, the efficiency at the system frequency of f0 is relatively lower than that at a shifted frequency of f′. To use the system at f0 effectively, the values of capacitors of resonators are optimized. The appropriate values of capacitors are found from the genetic algorithm by analytic calculation. This optimum design method is verified by both simulation and measurement. Additionally, the currents and dissipated powers on the resonators are investigated to explain the mechanism of optimization. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1658–1661, 2014
RHCP pattern‐reconfigurable spiral antenna biased with two DC signals
Authors: Gong Liang , Yang Yi , Chan King Y. , Ramer Rodica 
Published: April 2014

ABSTRACTA right‐hand circularly polarized beam steering spiral antenna is presented in this article. It is designed using the standard p‐i‐n technology, enhanced with arm switches and biasing lines. The ensuing design is easily manufactured and is functionally competitive with the more complex ones, based on RF‐MEMS. Three beams, tilted 40° with respect to the spiral central axis, are generated at 3.3 GHz, suitable for WiMax systems at this frequency. These beams are directed at approximately 90°, 180°, and 270° in the azimuth space. Beam directions depend on various configurations of the seven p‐i‐n diodes added to the spiral structure. The states of the diodes are subjected to the two DC bias voltages connected to the spiral arm. The radiation performance over the 200‐MHz bandwidth (3.2–3.4 GHz) is relatively stable. Measurements in this band show the reflection coefficient below −10 dB and the axial ratio below or close to 3 dB at the peak beam directions. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1636–1640, 2014
A dual‐band balanced amplifier using three‐layer technology
Authors: Hou Zhangju , Chiu Leung 
Published: April 2014

ABSTRACTA multilayer technology is applied to design a dual‐band branch‐line coupler for the dual‐band balanced amplifier. The proposed coupler is designed based on a three‐layer printed circuit board. The dual‐band operation is achieved by four additional shunt stubs at the middle layer, while the upper layer is the core and active circuits layer and the bottom is ground layer. The proposed coupler with equal power division is designed at two frequencies of 1.1 and 1.9 GHz. Besides, a balanced amplifier is also designed which achieves gain of 11.6 and 10.1 dB at 1.1 and 1.9 GHz, respectively. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1680–1683, 2014
Coupled‐sectorial‐loop antenna with circular sectors for super wideband applications
Authors: Yeo Junho , Lee Jong‐Ig 
Published: April 2014

ABSTRACTA coupled‐sectorial‐loop antenna (CSLA) with circular sectors is presented for super wideband (SWB) applications. Conventional CSLA consists of two parallel sectorial loop antennas connected along an axis of symmetry and triangular sectors are used. The average input impedance of the conventional CSLA is over 100 Ω, and a half of the CSLA above a ground plane is used to match with a 50‐Ω feed line. In the proposed antenna, circular sectors are used instead of triangular sectors to directly match with the 50‐Ω feed line, and the full structure of the CSLA is used. A prototype of the proposed antenna is fabricated on an FR4 substrate, and its performance is compared to the conventional CSLA. The experimental results show that the frequency band for a voltage standing wave ratio < 2.15 is 1.0–19.4 GHz (180.4%), which satisfies the requirement of the SWB antenna. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1683–1689, 2014
Design and characterization of a novel diamond resonator
Authors: Maricar Mohamed Ismaeel , Glover James , Evans Gwynne , Ata‐ul‐Khalid  , Cumming David , Oxley Chris 
Published: April 2014

ABSTRACTIn this article, the resonant frequency and quality factor of a novel coplanar waveguide (cpw) diamond‐shaped resonator were analyzed using advanced design system‐2009 momentum model software. The diamond resonator was compared with the cpw radial stub resonator on gallium arsenide (GaAs); the work indicated that the diamond resonator had a smaller physical size and higher quality factor (Q) at millimetric wave frequencies. Experimentally measured diamond cpw resonators fabricated on GaAs were in good agreement with the simulated results. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1691–1693, 2014
Development of passive millimeter wave imaging for concealed weapon detection indoors
Authors: Shi Xiang , Yang M.H. 
Published: April 2014

ABSTRACTThe passive millimeter wave (PMMW) imaging is often successful for outdoors as radiation of natural sky (cold source) provides the required contrast for imaging. When this method is used indoors, to detect weapons hidden inside the human body they fail detection due to the contrast between the target and subject being not obvious from lack of sky radiation. An active illumination although provides the desired contrast for the image recognition, but cause the image “blind” and “flicker” resulting in poor quality of imaging and target identification. This article describes a PMMW imaging security systems suitable for indoor usage. This system includes a large‐diameter parabolic antenna for convergence of target radiation, a front end array consisting of 9 94 GHz imaging radiometer, eight Ka‐band source with discrete frequency and discrete radiation direction to radiating harmonic illumination, and provide affordable energy “like noise” radiation, avoiding image's glint under coherent radiation. The results obtained from experiments on indoor detection of concealed weapon in human body validate the theory of proposed imaging systems, its feasibility, and practical utility. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1701–1706, 2014
A novel three vector sum active phase shifter design for W‐band automotive radar applications
Authors: Öztürk Efe , Tekin İbrahim 
Published: April 2014

ABSTRACTThis article presents a novel active W‐band phase shifter implemented using IHP SiGe Heterojunction Bipolar Transistor (HBT) 0.25‐µm SG25H1 technology with three vector (0°‐120°‐240°) sum technique. The integrated chip consists of a 3‐way Wilkinson power divider/combiner with 0°‐120°‐240° phase shifting lines and three low‐noise amplifiers (LNA) working at 77 GHz, which comprises a total of 1.5 × 1.1 mm2 die area. The phase shifting is based on the weighted sum of three vectors which have 120°‐angle separation so that all 360° could be scanned with simple amplitude control only. The LNAs are fabricated using IHP technology and can be used successfully in the active phase shifter design. LNA measurement results show that a variable gain of 0–14 dB at 77 GHz can be obtained by sweeping the base voltage between 1.8 and 2.3 V. The simulation results of complete system, including power dividers, phase shifting lines, LNAs, power combiners show that phase can be adjusted by 360° with a maximum gain of 1.8 dB. Input/output return loss for all the possible phase states are below 15 dB. The proposed phase shifter can be used in W‐band applications for full scan of 360°. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1715–1720, 2014
Spectral line suppression capabilities of spectral line free convolutional codes in UWB over fiber systems
Authors: Perez‐Ramos Aldo E. , Villarreal‐Reyes Salvador , Arvizu‐Mondragon Arturo , Lepers Catherine , Santos‐Aguilar Joel 
Published: April 2014

ABSTRACTThe topic of spectral line suppression is of major importance when designing impulse radio ultrawideband (IR‐UWB) systems. The presence of spectral lines in the power spectral density (PSD) may limit the maximum transmission power to comply with UWB regulations, thus, affecting the system performance. Although previous works have shown the advantages of IR‐UWB over fiber (UWBoF) implementations, the topic of spectral line suppression in PSD in such systems has not been entirely addressed. This letter proposes a simple IR‐UWBoF system using spectral line free (SLF) convolutional codes to address this topic. Experimental results show that the proposed system offers improved PSD characteristics compared to conventional IR‐UWBoF implementations. Furthermore, it is demonstrated that the proposed system is able to deliver SLF IR‐UWB signals over single‐mode fibers up to 30 km. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1712–1715, 2014
Erratum: New compact E‐plane microstrip‐to‐waveguide transition with slotted ground plane coupling
Authors: Gholami Mehrad , Yagoub M. C. E. 
Published: April 2014

ABSTRACTIn this article, a new compact microstrip‐to‐waveguide transition is presented. With 10% bandwidth for 20‐dB return loss and 0.2‐dB insertion loss, the proposed X‐ and Ku‐band designs are insensitive to manufacturing tolerances. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:615–619, 2014; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.28179. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1729, 2014
Blind multirigid retrospective motion correction of MR images
Authors: Loktyushin Alexander , Nickisch Hannes , Pohmann Rolf , Schölkopf Bernhard 
Published: April 2014

PurposePhysiological nonrigid motion is inevitable when imaging, e.g., abdominal viscera, and can lead to serious deterioration of the image quality. Prospective techniques for motion correction can handle only special types of nonrigid motion, as they only allow global correction. Retrospective methods developed so far need guidance from navigator sequences or external sensors. We propose a fully retrospective nonrigid motion correction scheme that only needs raw data as an input.MethodsOur method is based on a forward model that describes the effects of nonrigid motion by partitioning the image into patches with locally rigid motion. Using this forward model, we construct an objective function that we can optimize with respect to both unknown motion parameters per patch and the underlying sharp image.ResultsWe evaluate our method on both synthetic and real data in 2D and 3D. In vivo data was acquired using standard imaging sequences. The correction algorithm significantly improves the image quality. Our compute unified device architecture (CUDA)‐enabled graphic processing unit implementation ensures feasible computation times.ConclusionThe presented technique is the first computationally feasible retrospective method that uses the raw data of standard imaging sequences, and allows to correct for nonrigid motion without guidance from external motion sensors. Magn Reson Med 73:1457–1468, 2015. © 2014 Wiley Periodicals, Inc.
Iatrogenic Cushing Syndrome Secondary to a Probable Interaction Between Voriconazole and Budesonide
Authors: Jones Whitney , Chastain Cody A. , Wright Patty W. 
Published: April 2014

Oral budesonide is commonly used for the management of Crohn's disease given its high affinity for glucocorticoid receptors and low systemic activity due to extensive first‐pass metabolism through hepatic cytochrome P450 (CYP) 3A4. Voriconazole, a second‐generation triazole antifungal agent, is both a substrate and potent inhibitor of CYP isoenzymes, specifically CYP2C19, CYP2C9, and CYP3A4; thus, the potential for drug‐drug interactions with voriconazole is high. To our knowledge, drug‐drug interactions between voriconazole and corticosteroids have not been specifically reported in the literature. We describe a 48‐year‐old woman who was receiving oral budesonide 9 mg/day for the management of Crohn's disease and was diagnosed with fluconazole‐resistant Candida albicans esophagitis; oral voriconazole 200 mg every 12 hours for 3 weeks was prescribed for treatment. Because the patient experienced recurrent symptoms of dysphagia, a second 3‐week course of voriconazole therapy was taken. Seven weeks after originally being prescribed voriconazole, she came to her primary care clinic with elevated blood pressure, lower extremity edema, and weight gain; she was prescribed a diuretic and evaluated for renal dysfunction. At a follow‐up visit 6 weeks later with her specialty clinic, the patient's blood pressure was elevated, and her physical examination was notable for moon facies, posterior cervical fat pad prominence, and lower extremity pitting edema. Iatrogenic Cushing syndrome due to a drug‐drug interaction between voriconazole and budesonide was suspected, and voriconazole was discontinued. Budesonide was continued as previously prescribed for her Crohn's disease. On reevaluation 2 months later, the patient's Cushingoid features had markedly regressed. To our knowledge, this is the first published case report of iatrogenic Cushing syndrome due to a probable interaction between voriconazole and oral budesonide. In patients presenting with Cushingoid features who have received these drugs concomitantly, clinicians should consider the potential drug interaction between these agents, and the risks and benefits of continued therapy must be considered.
Autonomous Black Hawk in Flight: Obstacle Field Navigation and Landing‐site Selection on the RASCAL JUH‐60A
Authors: Whalley Matthew S. , Takahashi Marc D. , Fletcher Jay W. , Moralez Ernesto , Ott LTC Carl R. , Olmstead LTC Michael G. , Savage James C. , Goerzen Chad L. , Schulein Gregory J. , Burns Hoyt N. , Conrad Bill 
Published: April 2014

This paper describes the development and flight test of autonomous obstacle field navigation and safe landing area selection on the U.S. Army Aeroflightdynamics Directorate RASCAL JUH‐60A research helicopter. Using laser detection and ranging (LADAR) as the primary terrain sensor, the autonomous flight system is able to avoid obstacles, including wires, and select safe landing sites. An autonomous integrated landing zone approach profile was developed and validated that integrates cruise flight, low‐level terrain flight, and approach to a safe landing spot determined on the fly. Results are presented for a range of sites and conditions. Approximately 750 km of autonomous flight was performed, 230 km of which was at low altitude in mountainous terrain using the obstacle field navigation system. This is the first time a full‐scale helicopter has been flown fully autonomously a significant distance in low‐level flight over complex terrain, basing its planning solely on sensor data gathered from an onboard sensor. These flights demonstrate tight integration between terrain avoidance, control, and autonomous landing.
A modest proposal for dropping poor arms in clinical trials
Authors: Proschan Michael A. , Dodd Lori E. 
Published: April 2014

AbstractThis paper presents a simple procedure for clinical trials comparing several arms with control. Demand for streamlining the evaluation of new treatments has led to phase III clinical trials with more arms than would have been used in the past. In such a setting, it is reasonable that some arms may not perform as well as an active control. We introduce a simple procedure that takes advantage of negative results in some comparisons to lessen the required strength of evidence for other comparisons. We evaluate properties analytically and use them to support claims made about multi‐arm multi‐stage designs. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.
Step‐up testing procedure for multiple comparisons with a control for a latent variable model with ordered categorical responses
Authors: Lin Yueqiong , Kwong Koon Shing , Cheung Siu Hung , Poon Wai‐Yin 
Published: April 2014

AbstractIn clinical studies, multiple comparisons of several treatments to a control with ordered categorical responses are often encountered. A popular statistical approach to analyzing the data is to use the logistic regression model with the proportional odds assumption. As discussed in several recent research papers, if the proportional odds assumption fails to hold, the undesirable consequence of an inflated familywise type I error rate may affect the validity of the clinical findings. To remedy the problem, a more flexible approach that uses the latent normal model with single‐step and stepwise testing procedures has been recently proposed. In this paper, we introduce a step‐up procedure that uses the correlation structure of test statistics under the latent normal model. A simulation study demonstrates the superiority of the proposed procedure to all existing testing procedures. Based on the proposed step‐up procedure, we derive an algorithm that enables the determination of the total sample size and the sample size allocation scheme with a pre‐determined level of test power before the onset of a clinical trial. A clinical example is presented to illustrate our proposed method. Copyright © 2014 John Wiley & Sons, Ltd.