bluuebunny/crossref_metadata_2025_split huggingface dataset:
A dual‐band Wilkinson power divider with bandwidth enhancement
Authors: Xi Li , Yang Lin , Gong Shu‐xi , Yang Yan‐jiong 
Published: June 2009

AbstractThe design and analysis of a novel dual‐band equal‐split Wilkinson power divider are presented in this article. The proposed structure has no extra lumped and distributed elements. Moreover, the measured bandwidth of the proposed structure is more than 240 MHz for S11<‐20 dB. The formulas used to determine the design parameters have been given. Closed‐form design equations are derived using Z‐parameters matrix. For verification, a microwave power divider operating at 1 and 2.6 GHz is fabricated, the experimental results show that the designed power divider fulfills all the features of a conventional Wilkinson power divider, such as an equal power split and impedance matching at ports. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2043–2046, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24572
90‐Degree H‐plane bent waveguide using dielectric rods
Authors: Kokubo Yoshihiro , Kawai Tadashi 
Published: June 2009

AbstractConventional rectangular metallic waveguides are seldom used at frequencies higher than twice cutoff because of higher mode propagation. However, single‐mode propagation can occur for a metallic waveguide composed of an array of dielectric rods. An efficient way to construct one is to introduce dielectric rods at the bent portions because mode conversion does not occur in straight segments. As an example of the ease of fabrication, holes can be drilled at the top of a waveguide and dielectric rods inserted. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2015–2017, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24573
CPW‐fed dual‐mode resonators with double‐ring and double‐square‐loop for dual‐band applications
Authors: Liu Ji‐Chyun , Wang Jhih‐Wei , Kuei Ching‐Pin , Zeng Bing‐Hao 
Published: June 2009

AbstractThe CPW‐fed configurations of dual‐mode double‐ring resonator (DMDRR) and double‐square‐loop (DMDSLR) are introduced to achieve the performance of the dual‐band filters. To obtain lower insertion loss, higher out‐of‐band rejection level, and wider band of DMDRR and DMDSLR filters, using two twin‐T couples and dual‐mode perturbations are proposed here. Simulation and measurement results including surface current distributions and frequency responses are presented and discussed. It can be applied to 0.9 and 1.2 GHz dual‐band systems. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2010–2015, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24574
Compound field integral equation approach for analyzing quasi‐waveguide structures
Authors: Golestanirad Laleh , Mattes Michael , Mosig Juan R. 
Published: June 2009

AbstractIn this article, a compound field integral equation approach has been applied to analyze the problem of quasi‐waveguide structures, that is, structures consisting of a main waveguide with a constant cross section that may bear an arbitrary number of printed circuits backed by dielectric substrates. A detailed mathematical procedure is described to retrieve modal scattering parameters conventionally defined in planar multilayered structures excited by wave ports. In the case that the structure as well as the excitation holds symmetry requirements, simplifications may be applied to considerably improve the usage of computational resources. Formulations providing the theoretical background for applying symmetry conditions have also been developed in the context of this work. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2181–2186, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24575
Design of CMOS T/R switch using high‐substrate isolation and RF floated body for 1.9‐GHz applications
Authors: Lin Yih‐Hsia , Chu Chun‐Hsueh , Chang Da‐Chiang , Gong Jeng , Juang Ying‐Zong 
Published: June 2009

AbstractIn this work, two single‐pole, double‐throw CMOS transmit/receive (T/R) switches are designed for 1.9‐GHz application. Of the two T/R switches, one adopts single‐transistor architecture; the other adopts transistor‐stacking architecture to get a higher power‐handling capability. Both of the T/R switches make use of optimized transistor sizes to inherently achieve low‐insertion loss. In addition, techniques including high‐substrate isolation between transistors and RF floated body are used to further enhance the input 1‐dB compression point (IP1dB) and reduce the insertion loss of the T/R switches. The T/R switch with stacking architecture achieves a measured IP1dB of 23.5 dBm and an insertion loss of 1 dB at 1.9 GHz. The T/R switch using single‐transistor architecture achieves a very low‐insertion loss of 0.57 dB and a measured IP1dB of 21.6 dBm at 1.9 GHz. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2145–2149, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24577
Bandwidth enhancement of a quarter‐wavelength slot antenna by capacitive loading
Authors: Liu Zidong , Boyle Kevin 
Published: June 2009

AbstractIn this article, a novel wideband slot antenna is proposed. The slot is quarter‐wavelength long and loaded with a capacitor to increase its bandwidth. The effect of the capacitor on the antenna radiation efficiency is also investigated. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2114–2116, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24579
A low‐power wideband CMOS low‐noise amplifier using current‐reuse technique
Authors: Hsu Meng‐Ting , Lin Shih‐Kai 
Published: June 2009

AbstractA CMOS low noise amplifier (LNA) for low‐power ultra‐wideband wireless applications is presented. To achieve low power consumption and wide operating bandwidth, the proposed LNA uses a current‐reused technique and a simple high‐pass input matching network. This work is implemented in 0.18‐μm CMOS process technology and shows a 3.1–10.6 GHz bandwidth. With only 1.5 V supply voltage, the LNA can achieve power flat gain of 13.2 dB with input matching of −10.3 dB, the minimum noise figure of 3.33 dB, and input third‐order‐intercept point (IIP3) of −3.3 dBm. The power dissipation is only 9.3 mW. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2077–2080, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24581
Small‐size microstrip‐coupled printed PIFA for 2.4/5.2/5.8 GHz WLAN operation in the laptop computer
Authors: Wong Kin‐Lu , Chen Wei‐Ji 
Published: June 2009

AbstractWith a microstrip‐coupled feed, a small‐size (9 × 10 mm2) printed PIFA capable of generating two wide bands to cover WLAN operation in the 2.4 GHz and 5.2/5.8 GHz bands for laptop computer application is presented. The PIFA is easily printed on a thin, inexpensive FR4 substrate at low cost. Although, the printed PIFA provides a resonant path of about 20 mm only (about 0.16 wavelength at 2.4 GHz), far less than the required resonant length for the conventional quarter‐wavelength mode excitation and hence showing large inductive reactance at around 2.4 GHz, the applied microstrip‐coupled feed in this study effectively compensates for it to result in a resonance (zero reactance) at about 2.4 GHz. A desired resonant mode for covering 2.4 GHz WLAN operation is thus excited for the proposed small‐size printed PIFA. In addition, a higher‐order resonant mode at about 5.5 GHz is also generated to cover the 5.2/5.8 GHz WLAN operation. Details of the proposed PIFA are described, and results of the fabricated prototype are presented and discussed. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2072–2076, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24582
Broadband small‐size wire cone antenna
Authors: Kyi Yu Yu , Jianying Li 
Published: June 2009

AbstractThe broadband characteristic of wire cone antenna is presented in this article. The size reduction of top loading wire cone antenna is done by using inductive posts and lumped resistor loading. The broadband result of frequency span from 100–800 MHz over of VSWR < 2 was obtained. The wire cone antenna with top capacitive loading and resistor loading design was fabricated, and the measured results are compared with the simulation results. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2040–2043, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24583
Lateral and axial displacements measurement using fiber optic sensor based on beam‐through technique
Authors: Yasin M. , Harun S. W. , Fawzi W. A. , Kusminarto  , Karyono  , Ahmad H. 
Published: June 2009

AbstractThe performance of the fiber‐optic displacement sensor with beam‐through detection technique is investigated. The effects of lateral and axial displacements on the detected output voltage are investigated for various core's diameters of the sensor. The highest sensitivity is obtained at 0.0008 mV/μm for the lateral displacement with core's diameters for both transmitting and receiving fibers are fixed at 0.5 mm. At present, the widest linear range is obtained at 3195 μm for the axial displacement with 1.0 mm core's diameters for both fibers. The highest resolution of the 13 μm is obtained with the lateral displacement sensor with 0.5 mm core diameter. The sensor with the smaller core shows a better sensitivity and resolution with the expense of the smaller linear range. The beam‐through sensors have a simple design, high degree of sensitivity and dynamic range, and low cost. These make the sensors are useful for microdisplacement measurement in the hazardous region. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2038–2040, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24584
An independently tunable second‐passband by spiral open stubs in dual‐band HTS filter design
Authors: Li Mingjie , Jin Shichao , Guo Xubo , Wei Bin , Zhang Xiaoping , Cao Bisong , Gao Baoxin 
Published: June 2009

AbstractThis article presents a novel dual‐band HTS filter using open‐loop stepped impedance resonators (SIRs) and λ/4 spiral open stubs. The center frequencies of the two passbands are determined by the structure of the SIRs. By introducing the λ/4 spiral open stubs, the external quality factor of the second passband can be tuned independently without influence on that of the first one. The measured results of the filter at 77 K are in good agreement with the simulated ones. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2007–2010, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24585
A CMOS fully integrated concurrent dual ultrawideband receiver frontend
Authors: Chirala Mohan K. , Nguyen Cam 
Published: June 2009

AbstractA new fully integrated receiver front‐end operating concurrently over the two bands of 3.1–4.8 and 6.3–7.9 GHz of the UWB spectrum (3.1–10.6 GHz) has been developed using a 0.18‐μm CMOS process. The receiver front‐end occupies a chip size of only 1.18 × 0.87 mm2and exhibits conversion gains from 12.5–16.5 dB and 14.5–16 dB and RF return losses from 10 to 11 dB and 10.5 to 12 dB over the 3.1–4.8 GHz and 6.3–7.9 GHz bands, respectively. The measured input 1‐dB compression points are −4.1 and −5.2 dBm at 4 and 6.5 GHz, respectively. The measured noise figure is from 7.5 to 12.5 dB across 3.1–7.9 GHz and less than 10 dB up to 7 GHz. The receiver front‐end consumes about 42 mA of current from a 1.8 V power supply. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2003–2007, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24586
Wideband integrated CPS‐fed dual polarized quasi bow‐tie antenna
Authors: Vahdani Mohammad , Begaud Xavier 
Published: June 2009

AbstractA wideband integrated dual polarized bow‐tie antenna using an optimized microstrip‐to‐CPS transition has been presented in this article. This antenna has been designed and fabricated in a very compact geometry with overall dimensions of 1.1λL × 1.1λL × 0.015λL where λL is the wavelength at the lowest operating frequency. Measurement and simulation results show wideband behavior in dual polarization with return loss better than 10 dB from 5.4 to 12 GHz. The radiation patterns show good symmetrical patterns in E‐ and H‐plane. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2130–2136, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24588
Solving the steady‐state groundwater flow equation for finite linear aquifers using a generalized Fourier series approach in two‐dimensional domains
Authors: Capilla Jose E. , Pulido‐Velazquez David , Sahuquillo Andrés , Andreu Joaquín 
Published: June 2009

AbstractA method to solve steady linear groundwater flow problems using generalized Fourier Series is developed and particularized for multiple Fourier series in two‐dimensional domains. It leads to a linear vector equation whose solution provides a finite number of generalized Fourier coefficients approximating the hydraulic head field. Its implementation is shown and two relevant properties are found for the system matrix. It is always symmetric and, once computed, if additional Fourier terms are needed for a better approximation of the hydraulic head field, previously computed matrix elements remain invariant, i.e. only new rows and columns are added to the system matrix. The method is demonstrated in three simple cases with different geometries and transmissivity fields, where solutions are compared with analytical and finite element method results. Thus, the method is verified as an alternative to other flow solvers. Additionally, it provides a direct way to obtain the spectral form of the flow equation solution, given a spectral representation of transmissivity, and can be easily extended to obtain continuous velocity fields and their approximated spectral expressions. Copyright © 2009 John Wiley & Sons, Ltd.
A Padé‐based factorization‐free algorithm for identifying the eigenvalues missed by a generalized symmetric eigensolver
Authors: Avery P. , Farhat C. , Hetmaniuk U. 
Published: June 2009

AbstractWhen computing the solution of a generalized symmetric eigenvalue problem of the form Ku=λMu, the Sturm sequence check, also known as the inertia check, is the most popular method for reporting the number of missed eigenvalues within a range [σL,σR]. This method requires the factorization of the matrices K−σLM and K−σRM. When the size of the problem is reasonable and the matrices K and M are assembled, these factorizations are possible. When the eigensolver is equipped with an iterative solver, which is nowadays the preferred choice for large‐scale problems, the factorization of K−σM is not desired or feasible and therefore the inertia check cannot be performed. To this effect, the purpose of this paper is to present a factorization‐free algorithm for detecting and identifying the eigenvalues that were missed by an eigensolver equipped with an iterative linear equation solver within an interval of interest [σL,σR]. This algorithm constructs a scalar, rational, transfer function whose poles are exactly the eigenvalues of the symmetric pencil (K, M), approximates it by a Padé expansion, and computes the poles of this approximation to detect and identify the missed eigenvalues. The proposed algorithm is illustrated with an academic numerical example. Its potential for real engineering applications is also demonstrated with a large‐scale structural vibrations problem. Copyright © 2009 John Wiley & Sons, Ltd.
An energy approach to space–time Galerkin BEM for wave propagation problems
Authors: Aimi A. , Diligenti M. , Guardasoni C. , Mazzieri I. , Panizzi S. 
Published: June 2009

AbstractIn this paper we consider Dirichlet or Neumann wave propagation problems reformulated in terms of boundary integral equations with retarded potential. Starting from a natural energy identity, a space–time weak formulation for 1D integral problems is briefly introduced, and continuity and coerciveness properties of the related bilinear form are proved. Then, a theoretical analysis of an extension of the introduced formulation for 2D problems is proposed, pointing out the novelty with respect to existing literature results. At last, various numerical simulations will be presented and discussed, showing unconditional stability of the space–time Galerkin boundary element method applied to the energetic weak problem. Copyright © 2009 John Wiley & Sons, Ltd.
Approximate imposition of boundary conditions in immersed boundary methods
Authors: Codina Ramon , Baiges Joan 
Published: June 2009

AbstractWe analyze several possibilities to prescribe boundary conditions in the context of immersed boundary methods. As basic approximation technique we consider the finite element method with a mesh that does not match the boundary of the computational domain, and therefore Dirichlet boundary conditions need to be prescribed in an approximate way. As starting variational approach we consider Nitsche's methods, and we then move to two options that yield non‐symmetric problems but that turned out to be robust and efficient. The essential idea is to use the degrees of freedom of certain nodes of the finite element mesh to minimize the difference between the exact and the approximated boundary condition. Copyright © 2009 John Wiley & Sons, Ltd.
A Simple Method for Identification of the Parameters of the Fractional Kelvin‐Voight Model
Authors: Lewandowski Roman , Chorazyczewski Bartosz 
Published: June 2009

AbstractA major difficulty connected with fractional rheological models is the estimation of the model parameters of experimental data. A new method for identification of the parameters of the fractional Kelvin‐Voight model is presented. The procedure has been validated using artificial data and then used in estimating parameters from experimental data. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Synthesis and characterization of polyaniline/silicon dioxide composites and preparation of conductive films
Authors: Zengin Huseyin , Erkan Belgin 
Published: June 2009

AbstractThe focus of this study was to synthesize the inherently conductive polymer polyaniline using an optimized process to prepare polyaniline/silicon dioxide (PANI/SiO2) composites by in situ polymerization and ex situ solution mixing. PANI and PANI/SiO2 composite films were prepared by drop‐by‐drop and spin coating methods. The electrical conductivities of HCl doped PANI film and PANI/SiO2 composite films were measured according to the standard four‐point‐probe technique. The composite films exhibited an increase in electrical conductivity over neat PANI. PANI and PANI/SiO2 composites were also investigated by spectroscopic methods including UV‐Vis, FT‐IR, and Photoluminescence. UV‐Vis and FT‐IR studies showed that SiO2 particles affect the quinoid units along the polymer backbone and indicate strong interactions between the SiO2 particles and the quinoidal sites of PANI (doping effect). The photoluminescence properties of PANI and PANI/SiO2 composites were studied and the PANI/SiO2 composites showed increased intensity as compared to neat PANI. The increase of conductivity of PANI/SiO2 composite may be partially due to the doping or impurity effect of SiO2 where the silicon dioxides compete with chloride ions. The morphology of particles and films were examined by a scanning electron microscope (SEM). SEM measurements indicated that the SiO2 were well dispersed and isolated in composite films. Copyright © 2009 John Wiley & Sons, Ltd.
Structural understanding of stabilization patterns in engineered bispecific Ig‐like antibody molecules
Authors: Jordan Jacob L. , Arndt Joseph W. , Hanf Karl , Li Guohui , Hall Janine , Demarest Stephen , Huang Flora , Wu Xiufeng , Miller Brian , Glaser Scott , Fernandez Erik J. , Wang Deping , Lugovskoy Alexey 
Published: June 2009

AbstractBispecific immunoglobulin‐like antibodies capable of engaging multiple antigens represent a promising new class of therapeutic agents. Engineering of these molecules requires optimization of the molecular properties of one of the domain components. Here, we present a detailed crystallographic and computational characterization of the stabilization patterns in the lymphotoxin‐beta receptor (LTβR) binding Fv domain of an anti‐LTβR/anti‐TNF‐related apoptosis inducing ligand receptor‐2 (TRAIL‐R2) bispecific immunoglobulin‐like antibody. We further describe a new hierarchical structure‐guided approach toward engineering of antibody‐like molecules to enhance their thermal and chemical stability. Proteins 2009. © 2009 Wiley‐Liss, Inc.
Ligand unbinding from the estrogen receptor: A computational study of pathways and ligand specificity
Authors: Burendahl Sofia , Danciulescu Cristian , Nilsson Lennart 
Published: June 2009

AbstractThe estrogen receptor (ER) belongs to the nuclear receptor superfamily, whose members regulate important cellular events like development and metabolism. The ER functions as a transcription regulator and can be activated on ligand binding. Consequently, ligand binding and unbinding constitute fundamental processes in the regulation of genes. Even though both biochemical and structural data of ER are available, the actual mechanism of the ligand binding/unbinding remains elusive. We have performed computational studies on the unbinding mechanism of ERα and ERβ, in the presence of cofactors and with ligands ranging from agonist to a full antagonist. Our results show that agonists or selective ER modulators can dissociate from the receptor through multiple pathways with minor effect on the receptor structure, whereas an antagonist requires larger conformational changes. Furthermore, a specific receptor/ligand combination can exhibit a pathway preference depending on character and conformation of both parts. Hence, it is possible that the binding/unbinding mechanism can explain ligand subtype specificity and thus have an impact in drug discovery. Proteins 2009. © 2009 Wiley‐Liss, Inc.
Modularity of intrinsic disorder in the human proteome
Authors: Pentony Melissa M. , Jones David T. 
Published: June 2009

AbstractPredicting regions of disorder has become of increasing interest when determining protein structure and function. With ∼33% of eukaryotic proteins having significant disordered regions, and an increasing occurrence of disorder in higher organisms, an analysis of the importance of disorder from an evolutionary perspective was clearly warranted. Focusing on the human proteome, we have studied how abundant disorder is and its relevance to protein function and structure. We have shown that disordered regions frequently appear to be independent functional units, and judged by complete association to certain protein domains, may be evolutionarily conserved. Our work also supports previous analyses on association between disorder and alternate splicing and provides support for the modularity of disorder by showing that with respect to splicing events, disordered regions frequently appear to be spliced as whole units. Proteins 2010. © 2009 Wiley‐Liss, Inc.