bluuebunny/crossref_metadata_2025_split huggingface dataset:
Resonant frequency of a shorted circular patch with the use of a modified impedance expression for a metallic post
Authors: Chakravarty Tapas , De Asok 
Published: August 2002

AbstractThe accuracy of the cavity‐model analysis of a shorting post loaded circular microstrip antenna depends strongly on the exact modeling of the metallic post in the radial guide. This Letter presents an empirically generated expression for the impedance of such a post. The expression takes the edge effects into account, and its use results in a very accurate prediction of resonant frequency for all the eigenmodes of a shorting post loaded circular patch. The theoretical model is extensively compared with measured/simulated results and shows excellent agreement. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 33: 252–256, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10290
A new microstrip patch antenna for mobile communications and bluetooth applications
Authors: Paul Binu , Mridula S. , Aanandan C. K. , Mohanan P. 
Published: August 2002

AbstractA compact multiband planar octagonal‐shaped microstrip antenna simultaneously suitable for mobile communication and blue tooth application is presented. The antenna provides sufficient isolation between the two operating bands and an area reduction of ≈29 % with respect to a circular patch operating in the same band. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 33: 285–286, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10297
Estimation of the radiation patterns of diverging/focusing type of leakywave antennas
Authors: Ohtera Isao 
Published: August 2002

AbstractIn this article, an extension of “field regions” to estimate simply and qualitatively the feature of the radiation patterns for the diverging/focusing systems with the inherent phase error on their aperture is discussed and applied to the curved leakywave structure. The result will be especially useful relating to the design of the curved leakywave structure in the microwave/mm‐wave applications. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 33: 358–360, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10321
Broadband dual‐frequency coplanar probe‐fed patch antenna for GSM/DCS/PCS base stations
Authors: Chang Fa‐Shian , Wong Kin‐Lu 
Published: August 2002

AbstractThis article presents a novel air‐substrate patch antenna backed by a U‐shaped ground plane and excited by a coplanar probe feed for broadband dual‐frequency operation. The obtained impedance bandwidth (1:1.5 VSWR) of the antenna's lower band reaches 388 MHz (or nearly about 50% referenced to the center frequency at 787 MHz) and covers the GSM band (880–960 MHz); the upper band has a bandwidth as large as 575 MHz (or about 30% referenced to the center frequency at 1950 MHz) and covers both the DCS band (1710–1880 MHz) and the PCS band (1850–1990 MHz). Good broadside radiation characteristics for the proposed antenna have also been observed. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 33: 370–372, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10325
Compact dual‐frequency dual‐polarized slotted microstrip patch antenna
Authors: Binoy G. S. , Aanandan C. K. , Mohanan P. , Vasudevan K. 
Published: August 2002

AbstractA new design for the compact single‐feed dual‐frequency operation of a slotted square microstrip antenna is demonstrated. The antenna generates two distinct operating frequencies with different polarization planes and broad radiation characteristics. The antenna has the added advantage of an antenna size reduction as large as ∼61 and 45% in comparison to the standard rectangular patch for the above two frequencies. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 29: 60–62, 2001.
Increasing the radiation efficiency of cellular telephones by controlling the nearby electromagnetic field around a human model
Authors: Hankui Eiji , Hashimoto Osamu 
Published: August 2002

AbstractA new approach for increasing the radiation efficiency of cellular telephones, which controls the nearby magnetic field incident to a human phantom surface, has been proposed. To control the near field, a small magnetic plate is used as an electromagnetic perturbator, and it is placed near the antenna on the human side. Using the finite‐difference time‐domain (FDTD) method, it is clarified that our approach using the magnetic plate improves the radiation efficiency in practical usage (i.e., when a human phantom model is located near the antenna) by the effect of the magnetic plate, while keeping the antenna performance in the case of free space (i.e., without a human model) almost the same. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 29: 104–107, 2001.
Comparison of path loss and time‐delay spread in regular and chaflane street corners for microcellular communications
Authors: Luis‐Rodríguez Jorge , Juan‐Llácer Leandro 
Published: August 2002

AbstractA ray‐tracing model based on the application of the uniform theory of diffraction (UTD) and geometrical optics (GO) for modeling the propagation in microcellular urban scenarios has been implemented. A comparison with the simulation of published results validates our model. This model has been used to analyze some propagation characteristics (path loss and rms delay spread) in two street‐corner environments—regular and chaflane street corners. The study of the environments of the two corners shows that differences in the predictions are basically caused by the rays reflected on the walls of the chaflane corners. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 29: 139–142, 2001.
Three‐port rectangular microstrip unequal power divider and coupler
Authors: Ray Sudhabindu , Kumar Girish 
Published: August 2002

AbstractA new configuration of a three‐port rectangular microstrip power divider and coupler has been proposed. It can easily implement unequal power division of a large ratio, i.e., the power coupled to the third port can vary from −3 to −26 dB. The configuration has been analyzed using a transmission‐line model, as well as method‐of‐moments‐based software. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 29: 219–223, 2001.
Design of a 35 GHz microstrip tapered‐array antenna with wide detection range
Authors: Lee Youngju , Jung Myoung Suk , Park Wee Sang , Choi Jae Hyun 
Published: August 2002

AbstractThis paper describes a microstrip array antenna designed to operate at 35 GHz, and used as a position detector of moving targets. To obtain a wide detection range, the array was arranged to have a relatively narrower beamwidth in the elevation plane compared to the beamwidth in the azimuthal plane. This was achieved by aligning the electric‐field plane of each element to the array axis. Employing a 3 dB tapered feed network, the array has a sidelobe level of less than −20 dB, while retaining a wide azimuthal beamwidth. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 29: 276–280, 2001.
Gain‐enhanced L‐band EDFA employing a 1550 nm band ring laser
Authors: Mahdi M. A. , Ahmad H. 
Published: August 2002

AbstractA unique method of upgrading a C‐band EDFA into a highly efficient L‐band EDFA is presented, incorporating a gain‐clamped amplifier (ring laser) that acts as a gain‐improving element in an unpumped erbium‐doped fiber. A gain improvement of 17.8 dB and noise figures <4.0 dB are measured for optimum settings. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 29: 282–284, 2001.
A floating attachment mode for arbitrary wire‐to‐surface connections
Authors: Taboada J. M. , Rodríguez J. L. , Obelleiro F. 
Published: August 2002

AbstractA floating attachment mode is presented here in order to improve the electromagnetic analysis of wire antennas attached to arbitrary surfaces when using the method of moments (MoM). This attachment mode overlaps the surface modes, allowing us to place the wire‐to‐surface connection at any point, independently of the surface mesh, even near or at geometrical discontinuities. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 30: 102–105, 2001.
Distributed inductance and resistance per‐unit‐length formulas for VLSI interconnects on silicon substrate
Authors: Ymeri H. , Nauwelaers B. , Maex Karen 
Published: August 2002

AbstractA new analytic model is presented (the model is based on the induced current density distribution inside silicon substrate) to calculate the frequency‐dependent distributed inductance and the associated distributed series resistance of silicon semiconducting VLSI interconnects. The validity of the proposed model has been checked by a comparison with CAD‐oriented modeling methodology in conjunction with a quasi‐TEM spectral‐domain approach. It is found that the silicon semiconducting substrate skin effect must be considered for the accurate prediction of the high‐frequency characteristics of VLSI interconnects. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 30: 302–304, 2001.
Optical generation of microwave signals using a directly modulated semiconductor laser under modulated light injection
Authors: Seo Young‐Kwang , Kim Ajung , Kim Jung‐Tae , Choi Woo‐Young 
Published: August 2002

AbstractWe have experimentally demonstrated a new optical microwave signal generation scheme using semiconductor lasers in a master–slave configuration, in which both lasers are directly modulated. The sidebands of the slave laser are locked to those of the master laser by the simple control of the applied modulation power. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 30: 369–370, 2001.
Development of a very low‐cost suspended‐substrate strip‐line configuration using nonconventional material
Authors: Karmakar Nemai Chandra 
Published: August 2002

AbstractA very low‐cost suspended‐substrate strip‐line configuration is developed using packaging foam and a very thin Cu‐clad glass–epoxy laminate. The material characteristics, such as effective dielectric constant, attenuation, and loss tangent, have been determined accurately using two different transmission measurement techniques. A λ/4‐long 50 Ω transmission line is fabricated on the developed configuration, and tested successfully. The measured insertion loss is less than 0.15 dB, and the return loss is greater than 35 dB over the entire L‐band. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 30: 413–416, 2001.
Radar target recognition using least squares estimate
Authors: Lee Joon‐Ho , Kim Hyo‐Tae 
Published: August 2002

AbstractA new scheme for radar target discrimination which is independent of an aspect angle is proposed in the frequency domain. A system of linear equations is constructed using the frequency response of an unknown target and stored natural frequencies of a particular target. Whether an unknown target is a particular target or not is determined using the defined least squares estimate or the normalized estimation error. The validity of the method is shown using the method‐of‐moments (MM) frequency response. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 30: 427–434, 2001.
Dielectric loss of multilayer coupled microstrip line using SLR formulation
Authors: Verma A. K. , Nasimuddin  , Bhupal A. 
Published: August 2002

AbstractThe single‐layer reduction (SLR) formulation is presented to compute the dielectric loss of even–odd modes of a multilayer coupled microstrip line. Results are compared against the results of full‐wave analysis with a maximum deviation of 2% for the wide range of parameters. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 31: 65–67, 2001.
Research on dynamics in modulation‐doped GaAs/AlxGa1−xAs heterostructures
Authors: Li Guo‐Hui , Zhou Shi‐Ping , Xu De‐Ming 
Published: August 2002

AbstractWe discuss the dynamics of the forced modulation‐doped AlxGa1−xAs heterostructure device governed by the coupled differential equations, which is operative in the state far from thermodynamic equilibrium. Biased with an appropriate dc field, the system exhibits two states: spontaneous current oscillation and fixed points. Under an ac driving force imposed on a dc bias, the dynamical system shows the expected characteristics of frequency locking, quasiperiodicity, and chaos, which are sensitive to the amplitude and frequency of the external applied microwave field. In particular, the basins of attraction of both an ordinary attractor and a chaotic attractor are presented. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 31: 93–95, 2001.
Design and fabrication of a miniature monoblock bandpass filter using high‐permittivity ceramic
Authors: Weng Min‐Hung , Liang Tsorng‐Juu , Huang Cheng‐Liang 
Published: August 2002

AbstractA miniature monoblock bandpass filter with combline‐type, quarter‐wavelength, and capacitive coupling is investigated. The coupling analysis and equivalent circuit consist of the transmission lines, and lumped elements are presented to predict the filter performance. A filter design technique based on the results of the equivalent‐circuit parameters is described. A miniature monoblock bandpass filter using (Zr0.8, Sn0.2)TiO4 ceramics is fabricated at a center frequency of 1600 MHz. Excellent experimental results of the fabricated filter measured by an HP8510B network analyzer verify the design specification. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 31: 95–97, 2001.
Optimized power dividers based on E‐plane T‐junctions
Authors: Gómez Ignacio , De Haro Leandro , Galocha Belen , Besada Jose L. 
Published: August 2002

AbstractA power divider is an essential component in the design of antenna feed networks for satellite applications. Asymmetrical E‐plane T‐junctions exhibit good electrical performances and a simplified mechanical process of construction. This paper study improved structures on this baseline. These are analyzed and optimized. Two different analysis methods have been used in order to check their results. Also, the results have been verified with commercial software. Both methods are based on the GSM (general scattering matrix) and modal analysis technique. The optimization process, based on quasi‐Newton approximations, allows obtaining, for instance, a power divider with five ports (four T‐junctions cascaded) with good electrical performances. A tolerance analysis has been carried out in order to study the feasibility of power dividers. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 31: 118–123, 2001.
Need for a cooperative study: Pulmonary langerhans cell histiocytosis and its management in adults
Authors: McClain Kenneth L. , Gonzalez Jorge Mario , Jonkers Rene , De Juli Emanuela , Egeler Maarten 
Published: August 2002

AbstractBackgroundPulmonary involvement with Langerhans cell histiocytosis (LCH, formerly known as histiocytosis‐X) presents as an interstitial process in children and adults either with or without symptoms. In contrast to other manifestations of LCH, most patients with pulmonary disease are adults.ProceduresWe reviewed the literature on pulmonary LCH to determine what were the clinical presentations, prognostic variables, and treatment options for this disease.ResultsAlthough there are spontaneous remissions, a large number of patients have progressive pulmonary deficiency and experience significant morbidity if not mortality from the disease. The efficacy of steroid versus chemotherapy in halting the process remains controversial, even if smoking is taken into consideration.ConclusionsA multicenter study of therapy for pulmonary LCH is the obvious answer to this dilemma. We propose that interested centers organize via the Histiocyte Society to plan and execute such a trial. Med Pediatr Oncol 2002;39:35–39. © 2002 Wiley‐Liss, Inc.
Antibody formation during intravenous and intramuscular therapy with Erwinia asparaginase*
Authors: Albertsen Birgitte Klug , Schrøder Henrik , Jakobsen Preben , Avramis Vassilios I. , Müller Hans‐Joachim , Schmiegelow Kjeld , Carlsen Niels T. 
Published: August 2002

AbstractBackgroundDetermination of the frequency of antibody formation during first and second exposure to Erwinia asparaginase after i.v. and i.m. administration.ProcedureThirty‐nine children with newly diagnosed acute lymphoblastic leukemia (ALL) were included in this prospective study. Antibodies were determined (ELISA method) in plasma from these patients on specific days during and after therapy with 30,000 IU/m2 i.v. or i.m. every day for ten days during the induction phase (first exposure). For 19 children, antibodies were measured in plasma during and after the re‐induction phase (second exposure) following treatment with 30,000 IU/m2 i.v. or i.m. twice a week for two weeks (Mondays and Thursdays). On the same days of therapy, enzyme activity (spectrophotometric method) and the concentration of asparagine (HPLC) was determined.ResultsDuring the first exposure, none of the patients developed anti‐Erwinia asparaginase antibodies. During the second exposure, one patient (1 of 8 patients) treated intravenously developed antibodies, which were associated with disappearance of enzyme activity and reappearance of asparagine. Three of eleven patients developed antibodies of pharmacokinetic importance after i.m. therapy. None of the children had any clinical symptoms of hypersensitivity.ConclusionsThe formation of antibodies and subsequently altered pharmacokinetics of Erwinia asparaginase seemed to be of importance only during a second period of asparaginase therapy. Med. Pediatr. Oncol. 2002;38:310–316. © 2002 Wiley‐Liss, Inc.
A fast magnetic resonance imaging technique for children with mediastinal lymphoma: Work in progress
Authors: Wagner Maren , Kuth Rainer , Deimling Michael , Rascher Wolfgang , Rupprecht Thomas 
Published: August 2002

AbstractBackgroundMediastinal lymphoma often presents as a large tumor at the time of diagnosis. Usually chest X‐ray filming is the first imaging modality and it is used for routine follow‐up during the course of the disease. A new and very fast MRI technique has been developed at our center as an alternative. Results in three patients with mediastinal lymphoma during a pilot study are promising.ProcedureAfter diagnosis the above patients were additionally investigated in a 0.2 T low‐field MR‐scanner by a modified true FISP sequence (see text) with an acquisition time of 3.6–4.6 sec. Follow‐up was performed by both, X‐ray filming and MRI. After diagnosis the patients, again, had both X‐ray filming and MRI investigation for follow‐up: one patient 2, one patient 3, and one patient 5 times. Images were evaluated and compared by two pediatric radiologists.ResultsTotal investigation times for radiography and MRI were comparable. The tumor was better visualized by MRI on seven of nine images and gave additional information about the structure and the localization of the tumor as well as concomitant problems such as pericardial effusion.ConclusionsTrue FISP MRI may prove to be a good alternative to X‐ray filming in the diagnosis and follow‐up of mediastinal lymphoma. Med Pediatr Oncol 2001;37:532–536. © 2001 Wiley‐Liss, Inc.
Distribution of the methyl radical adduct of N‐benzylidene‐1‐diethoxyphosphoryl‐1‐methylethylamine N‐oxide‐type nitrones in water–sodium dodecyl sulfate micelles: an electron paramagnetic resonance spin trapping study
Authors: Rizzi Cécile , Lauricella Robert , Bouteiller Jean‐Claude , Roubaud Valérie , Tuccio Béatrice 
Published: August 2002

AbstractThe behavior of the methyl radical adduct of six β‐phosphorylated nitrones in the N‐benzylidene‐1‐diethoxyphosphoryl‐1‐methylethylamine N‐oxide series in the presence of sodium dodecyl sulfate (SDS) micelles was followed by electron paramagnetic resonance spectroscopy. Except when the highly hydrophilic trap 4‐PyOPN (2) was used, all the adducts were found to partition significantly between micelles and the bulk aqueous phase. The average correlation time τ of the exchange of spin adducts between SDS micelles and water was found to be in the range 5 × 10−8—4 × 10−7 s, which is in the region of the life time of an SDS monomer in the micelle structure. In each case, the adduct affinity for the micelles has been quantified by evaluating its micelle–water distribution coefficient Kd. Copyright © 2002 John Wiley & Sons, Ltd.
General model of assignment of the relative stereochemistry in the Nicholas reaction products resulting from chiral dicobalthexacarbonyl‐1‐alkoxy‐propargylium cations
Authors: Montaña Angel M. , Cano Montserrat 
Published: August 2002

AbstractThe Nicholas reaction of chiral 1‐alkoxy‐dicobalthexacarbonyl‐propargylium cations with linear and/or cyclic silyl enol ethers resulted in the formation of two pairs of diastereoisomers (syn‐1, syn‐2 and anti‐1, anti‐2), depending on the relative stereochemistry of the two new stereocenters formed in the reaction products. Here, we present a model to establish the relative stereochemistry of those stereocenters on the basis of a correlation of their 1H and 13C NMR spectra, together with their conformational analysis and a study of the stereoelectronic interactions conditioning the chemical shifts and coupling constants. The importance of this method is based on its applicability to the assignment of the relative stereochemistry of non‐separable components of a diastereomeric mixture or, when diastereomers are non‐crystallizable oily products, not suitable for X‐ray diffraction analysis. Copyright © 2002 John Wiley & Sons, Ltd.
1H and 13C NMR spectral characterization of some antimalarial in vitro 2,4‐diamino‐10‐methylpyrimido[4,5‐b]‐5‐quinolone derivatives
Authors: Charris Jaime E. , Domínguez José N. , Gamboa Neira , Angel Jorge , Piña Nolberto , Guerra Mayamarú , Michelena Elba , López Simón E. 
Published: August 2002

AbstractWe report the 1H NMR and 13C NMR chemical shifts and J(H,H), J(H,F) and J(C,F) coupling constants of 13 2,4‐diamino‐10‐methylpyrimido[4,5‐b]‐5‐quinolone derivatives, some of them with moderate activity against Plasmodium falciparum in vitro. They were characterized and assigned on the basis of 1H, 13C and 13C–1H (short‐ and long‐range) correlated spectra. Copyright © 2002 John Wiley & Sons, Ltd.
NMR analyses of two isomeric cyclobutanes from a [2 + 2] photocycloaddition
Authors: Minter David E. , Winslow Christopher D. , Watson William H. , Bodige Satish 
Published: August 2002

AbstractComplete 1H and 13C NMR assignments are reported for two isomeric cyclobutanes generated from the photochemical [2 + 2] cycloaddition of N‐methylisocarbostyril and 4‐methoxy‐3‐buten‐2‐one. The reaction is 100% regioselective and demonstrates the potential synthetic utility of de Mayo type reactions using an isocarbostyril and a stable β‐dicarbonyl enol derivative. Copyright © 2002 John Wiley & Sons, Ltd.
Structural elucidation of bipyridine helicate complexes and their precursors by NMR spectroscopy
Authors: Annunziata Rita , Benaglia Maurizio , Famulari Antonino , Raimondi Laura 
Published: August 2002

Abstract1H and 13C NMR assignments of bipyridine helicate complexes and their precursor ligands were achieved using gradient‐based homo‐ and hetero‐correlated 2D experiments. The observed trends in 1H and 13C chemical shift variations [Δδ(H) and Δδ(C)], on passing from the ligands to the complexes, are accounted for on the basis of MO evaluation of atomic charges. Copyright © 2001 John Wiley & Sons, Ltd.
1H and 13C NMR assignments of 2‐oxo‐2H‐1‐benzopyran‐3‐acyl and ‐3‐amide derivatives
Authors: Martínez‐Martínez F. J. , Padilla‐Martínez I. I. , Trujillo‐Ferrara J. 
Published: August 2002

Abstract1H and 13C NMR spectral data for seven 2‐oxo‐2H‐1‐benzopyran‐3‐carboxamide and two 2‐oxo‐2H‐1‐benzopyran‐3‐amide derivatives are reported. The chemical shift assignments were based on two‐dimensional experiments. Copyright © 2001 John Wiley & Sons, Ltd.