bluuebunny/crossref_metadata_2025_split huggingface dataset:
Complex propagation constants for nonuniform optical waveguides: Calculations
Authors: Gallawa R. L 
Published: July 2007

AbstractA method of calculating the complex propagation constant of a planar optical waveguide under very general but weakly guiding conditions is derived. The method, based on Galerkin 's formalism using Hermite‐Gaussian basis functions, allows a nonuniform and complex refractive index profile. The real and imaginary parts of the index are allowed to vary independently and arbitrarily as a function of position. The planar waveguide is used so the results can be compared with exact solutions. The method is more general than this, however, and can be used with any geometry. The results are inherently stationary. © 1993 John Wiley & Sons, Inc.
Optimization of substrate dielectric and mode of microstrip ring antenna for high efficiency and directivity
Authors: Iyer S. M. Vaitheeswaran , Joshi A. W. , Karekar R. N. 
Published: July 2007

AbstractTheoretical formulation using the Green's function in conjunction with the reflection coefficient matrix approach (instead of potentials) is used for calculations of fields of microstrip ring antennas. Different TM modes are studied using the magnetic cavity wall model for obtaining ring sheet currents. The results show that the ring antenna is superior to disk and rectangular patch antennas and has optimized performance for the TM12 mode, with a substrate dielectric constant of 6 with high gain, broad lobe width and no side lobes. The better performance at higher r may be of importance for array synthesis in MMIC. The theoretical approach used is simpler for calculation and is easily extendable to other situations and higher substrate thicknesses. © 1993 John Wiley & Sons, Inc.
A unidirectionally conducting screen is a super‐brewster screen
Authors: Lakhtakia Akhlesh 
Published: July 2007

AbstractExpressions for the plane‐wave response of a unidirectionally conducting screen (UCS) embedded in a linear, homogeneous, bianisotropic substance are obtained. The ratio of the complex amplitudes of the two reflected plane waves is shown to be always independent of the ratio of the complex amplitudes of the two incident plane waves; likewise, for the transmitted plane waves. Thus, a UCS is a super‐Brewster screen. © 1993 John Wiley & Sons, Inc.
Mutual coupling in finite‐length thin wire chirostrip antennas
Authors: Pelet Philippe , Engheta Nader 
Published: July 2007

AbstractHere, we theoretically analyze the mutual coupling between two finite‐length thin wire chirostrip antennas. These antennas are defined as thin wires printed on grounded substrate made of chiral materials which exhibit electromagnetic handedness. Chiral materials are circular polarization (CP) birefringent and are described by the constitutive relations ε and ε with εc μc, and ε as material parameters. Mutual coupling for broadside, collinear, and echelon configurations for these antennas is investigated, and it is shown that introducing chirality in the substrate can, under certain circumstances, modify the mutual coupling between the chirostrip antennas. © 1993 John Wiley & Sons, Inc.
Maxwell‐garnett model for composites of electrically small uniaxial objects
Authors: Weiglhofer W. S. , Lakhtakia A. , Monzon J. C. 
Published: July 2007

AbstractComposites consisting of randomly dispersed, electrically small, uniaxial inclusions in an isotropic dielectric‐magnetic host material are homogenized in accordance with the Maxwell‐Garnett approach. The inclusions may be wire‐and‐loop models of helices or acicular bianisotropic bodies. Effective constitutive dyadics for the composites are found for various orientational arrangements of the inclusion objects. Furthermore, the inadequacy of current theoretical models for scattering from electrically small metal helices is discussed. © 1993 John Wiley & Sons, Inc.
A recursive aggregation method for the computation of electromagnetic scattering by randomly distributed particles
Authors: Lu Cai‐Cheng , Chew Weng Cho 
Published: July 2007

AbstractWe develop a new algorithm to expedite the matrix‐vector multiplication in using the conjugate gradient method to solve the linear algebraic equation of scattering by a cluster of particles. We compare this method of solving the scattering problem with two other methods. One is our previously developed method, called recursive aggregate T‐matrix method. The second one is the direct use of the conjugate gradient method. Our new method is shown to have reduced computational complexity as well as memory requirement compared to the use of the conjugate gradient directly to solve the linear algebraic equation of scattering. © 1993 John Wiley & Sons, Inc.
Electromagnetic scattering from skew‐symmetric metallic grids
Authors: Christodoulou C. G. 
Published: July 2007

AbstractIn many applications for reflector antennas, the reflector is made from flexible, conducting material. The wires are weaved together, forming a very complex structure to study. So far, these mesh structures have been approximated by rectangular grids. In this study, the mesh geometry is approximated by a skew‐symmetric grid. The FFT‐conjugate gradient method (FFT‐CGM) is employed to solve the problem of scattering from such grids. A convenient unit cell is chosen and utilized to study the effects of skewness on the reflection coefficients and current densities. Calculated values of the reflection coefficient for different angles of incidence for both the bonded and unbonded skewed gratings are presented and discussed. © 1993 John Wiley & Sons, Inc.
A NOTE ON THE TESTING FUNCTIONS USED IN THE METHOD‐OF‐MOMENTS SOLUTION OF THIN‐WIRE ANTENNA PROBLEMS
Authors: Rynne Bryan P. 
Published: July 2007

AbstractIt was observed in an article by Klein and Mittra that when the method of moments is used to solve thin‐wire antenna problems, erroneous, highly oscillatory solutions can occur when certain wide‐pulse testing functions are used. This article presents a possible explanation of the occurrence of these erroneous solutions. © 1993 John Wiley & Sons, Inc.
A note on the analysis of nonreciprocal phase shifters by the spectral index method
Authors: Shamonin M. , Erdmann A. , Hertel P. , Dötsch H. 
Published: July 2007

AbstractThe spectral index method is applied to nonreciprocal quasi‐TM mode phase shifters based on rib‐type waveguide structures. It compares well with the much slower finite‐difference method. © 1993 John Wiley & Sons, Inc.
An optical fuzzy matrix‐vector processor for implementing fuzzy associative memory
Authors: Zhang Shuqun , Lin Senmao , Chen Caisheng 
Published: July 2007

AbstractAn optical fuzzy matrix‐vector processor is designed to implement fuzzy associative memory. By spatial encoding and thresholding operation, the two basic operations needed by fuzzy associative memory, maximization and minimization, are realized optically. Experimental results are given as well. © 1993 John Wiley & Sons, Inc.
Wave propagation along a closed rectangular chirowaveguide
Authors: Cory H. 
Published: July 2007

AbstractWave propagation along a closed rectangular chirowaveguide is studied. The coupled differential equations governing the transverse variation of the transverse components of the electric field have been established and a zero‐order solution has been proposed. This solution provides the corresponding β ‐ ω diagram, whose characteristics are investigated. © 1993 John Wiley & Sons, Inc.
Hybrid analytical technique for waveguide coupling by means of apertures or slots
Authors: Sangster A. J. , Wang Hanyang 
Published: July 2007

AbstractA hybrid technique which combines the finite element method with the moment method is proposed for the analysis of waveguide coupling by means of irregular apertures or slots. An example is given to verify the validity of the hybrid technique, while the numerical predictions are supported by results obtained using conventional moment methods. © 1993 John Wiley & Sons, Inc.
Polarization properties of plane waves in transversely bianisotropic uniaxial medium
Authors: Koivisto Paivi 
Published: July 2007

AbstractTransversely bianisotropic uniaxial medium can be constructed by mixing metal helices into anisotropic host medium in such a way that the axes of the helices are perpendicular to a fixed direction in space but randomly oriented in the transverse plane. In general, the host medium can be either reciprocal or nonreciprocal. Eigenwaves, expressions for the plane‐wave fields, and polarization behavior are derived for the plane wave propagating perpendicular to the symmetry axis. The polarization properties of chiral and reciprocal transversely bianisotropic uniaxial medium are studied in order to find a suitable parameter combination for a polarization transformer. Several numerical examples are given to illustrate the propagation properties of the transversely bianisotropic uniaxial medium.
An integrated optical fabry‐perot modulator in LiNbO3
Authors: Liang Jia Yi , Wilson Mike G. F. 
Published: July 2007

AbstractThis letter presents a novel approach to low driving power optical modulation by using a waveguide resonator. A modified technique called etched lift off is used for electrode deposition. A modulation bandwidth of 1 GHz at 1.15 μm was achieved by a driving voltage of 1.5 V for 84% modulation.
A vector finite‐element analysis of complex modes in shielded microstrip lines
Authors: Alam Md. Shah , Hirayama Koichi , Hayashi Yoshio , Koshiba Masanori 
Published: July 2007

AbstractThe finite‐element method is employed to carry out the numerical analysis of complex modes, as well as propagating and evanescent modes in lossless shielded microstrip lines. In this finite‐element calculation, the triangular mixed element is used. The possible electric field distributions of the complex modes are also presented.
Optical‐fiber digital PPM systems employing PIN‐FET receivers
Authors: Cryan R. A. 
Published: July 2007

AbstractAn analysis is presented for the optimum detection of digital pulse position modulation employing PIN‐FET receivers. The results demonstrate a sensitivity improvement of 7.2 dB over an equivalent PCM system when operating at a bit rate of 50 Mbits/s. Calculations have also been performed for a causal approximation to the optimum receiver and it is shown that this leads to only a 0.5‐dB reduction in sensitivity. Finally, receiver design implications are examined for higher bit‐rate operation and the results obtained for a 565‐Mbit/s system demonstrate an improvement of 6 dB over PCM.
Microstrip antenna top‐loaded by a dielectric resonator
Authors: Yung Edward K. N. , Lee Wilson W. S. , Luk K. M. 
Published: July 2007

AbstractA cylindrical dielectric resonator is placed on top of a circular microstrip antenna. The resonant frequency and the input impedance of the antenna are altered. The bandwidth of the microstrip antenna is nearly doubled by the top loading. These changes are dependent on the displacement between the resonator and the patch. © 1994 John Wiley & Sons, Inc.
New photonic device integration by selective‐area MOVPE and its application to optical modulator/laser integration (invited paper)
Authors: Aoki M. , Suzuki M. , Taniwatari T. , Sano H. , Kawano T. 
Published: July 2007

AbstractThis article describes a novel fabrication technology for photonic integrated circuits (PICs) that easily produces a smooth and high‐quality waveguide coupling between interconnected guided‐wave elements. This technique is based on the in‐plane quantum energy control selective area metal‐organic vapor‐phase epitaxy of multiple‐quantum‐well (MQW) structures. Good local quantum energy control over a very wide range is shown for simultaneously grown MQW crystals. Moreover, the crystal quality, well/barrier heterointerface, and flatness and uniformity of these selectively grown MQW crystals are bound to be as good as those of normally grown crystals. This technique is applied to an electroabsorption modulator/distributed feedback laser integrated device. Superior device performance, including a low threshold and high‐efficiency lasing properties, as well as high‐speed, low‐drive‐voltage, and low‐chirp modulator characteristics are attained due to improved optical coupling, easy fabrication, and sufficient crystal quality of selectively grown MQW structures. 2.5 Gbit/s penalty‐free data transmission is demonstrated over an 80‐km normal single‐mode fiber, which, combined with long‐term device reliability, makes this integration technique more attractive for practical fabrication of semiconductor PICs. © 1994 John Wiley & Sons, Inc.
Fabrication of lithium niobate optical channel waveguides by nickel indiffusion
Authors: Wei Pei‐Kuen , Wang Way‐Seen 
Published: July 2007

AbstractSingly and randomly polarized nickel‐indiffused waveguides in lithium niobate were found when fabricated under different diffusion conditions. The randomly polarized waveguides are verified to have the advantages of no outdiffusion guiding layer and low diffusion temperatures. The linear electro‐optic coefficient was found only slightly decreased when checked using a Mach‐Zehnder interferometer. © 1994 John Wiley & Sons, Inc.
Design and performance of a microstrip flat reflect‐array antenna
Authors: Javor Ronald D. , Wu Xiao‐Dong , Chang Kai 
Published: July 2007

AbstractA simple method was used to design a microstrip flat reflect‐array antenna. An X‐band, 12‐element array of rectangular microstrip patches was demonstrated for the first time to reflect the main beam 20 degrees off broadside. A redirection efficiency of 65.8% was observed. © 1994 John Wiley & Sons, Inc.
Decoupled planar dipoles for subsurface cw interface radar
Authors: Park Dong‐Kook , Ra Jung‐Woong 
Published: July 2007

AbstractWideband decoupled planar dipoles are suggested for a subsurface transmitting and receiving antenna. Design parameters of the conductor‐backed cut‐off dielectric waveguide containing two planar dipoles above a lossy half space are suggested, and a bandwidth of more than 5 to 1, decoupling of ‐90 dB for about one wavelength separation are obtained. © 1994 John Wiley & Sons, Inc.
A simple new technique for the implementation of vertical currents into the SDA
Authors: John A. , Jansen R. H. 
Published: July 2007

AbstractThis contribution presents a new technique for implementing vertical currents into the spectral‐domain approach. Previously published methods require a drastic increase of spatial resolution and thus CPU time when adding vertical elements. Our technique avoids this by using partial Galerkin solutions without vertical expansion functions and by applying continuity conditions. © 1994 John Wiley & Sons, Inc.
A simple model for the gaas hbt high‐frequency performance under optical illumination
Authors: De Salles Alvaro A. , Hackbart Anelise S. , Spalding Luiz N. 
Published: July 2007

AbstractA simple theory and a model for the GaAs heterojunction bipolar transistor's (HBT's) high‐frequency performance under optical illumination are described. It is assumed that the major contribution to the photocurrent in the HBT is due to the photovoltaic effect in the base‐collector depletion region. Estimations using PSPICE circuit simulator show photoresponse cutoff frequencies of several tens of gigahertz when some HBT parameters are adequately designed. © 1994 John Wiley & Sons, Inc.
Dual polarized, single‐ and double‐layer strip‐slot‐foam inverted patch (ssfip) antennas
Authors: Zürcher J‐F. , Gay‐Balmaz Ph. , Hall R. C. , Kolb S. 
Published: July 2007

AbstractA new way of feeding an SSFIP antenna to obtain two orthogonal linear or two circular (RHCP/LHCP) polarizations is presented. The advantages of the method are its simplicity, a perfect symmetry of the structure and of the pattern, and an excellent decoupling between input ports. The enhanced element retains the desirable properties of conventional SSFIP elements: wide bandwidth, low cost, robustness, and low thickness and weight. © 1994 John Wiley & Sons, Inc.
Frequency dependence of the rcs of an arbitrarily shaped simple scatterer
Authors: Zhendong Shi , Hongwei Liu , Pu Tang 
Published: July 2007

AbstractThe frequency dependence of the RCS of an arbitrarily shaped simple scatterer is given, based on which model measurement of RCS can be made with testing equipment unchanged, even though the size of the model is sometimes scaled down with respect to that of the prototype. © 1994 John Wiley & Sons, Inc.
A novel highly selective and tunable optical bandpass filter using a fiber grating and a fiber fabry‐perot
Authors: Capmany J. , Laming R. I. , Payne D. N. 
Published: July 2007

AbstractWe present a novel continuously tunable optical bandpass filter composed of a FFP, on an optical circulator, and a fiber grating. The structure combines the high selectivity of the FFT and the bandpass nature of the fiber grating. © 1994 John Wiley & Sons, Inc.
A novel short‐range anticollision radar
Authors: Benlarbi A. , Leroy Y. 
Published: July 2007

AbstractAn original short‐range low‐cost anticollision CW microwave sensor is based on interferometry. It produces triggering signals when a reflective surface approaches the system and reaches predefined distances. In the examples described here, these distances are between several decimeters and a few meters. © 1994 John Wiley & Sons, Inc.
Variable gain amplifier with traveling wave structure
Authors: Floc'h J. M. , Desclos L. 
Published: July 2007

AbstractThis article presents a technique based on distributed structure in order to make a variable gain amplifier. A method to achieve a large dynamic gain range over a large frequency bandwidth is shown. The steps of design are presented and highlight a simple methodology. A two‐stage GCA (gain‐controlled amplifier) over a 2–12–GHz frequency bandwidth is shown and theoretical investigations for more complicated one are presented. © 1994 John Wiley & Sons, Inc.
Cad formulas for resonant frequencies of tm11 mode of circular patch antenna with or without superstrate
Authors: Lee Kai‐Fong , Fan Zhibo 
Published: July 2007

AbstractCurve‐fitting formulas based on moment‐method results are presented for the resonant frequency of the TM11 mode of a coaxially fed circular patch antenna with or without superstrate. The formulas can be used for a wide range of substrate and superstrate thicknesses and permittivities. Results predicted by these computer‐aided design formulas agree well with moment‐method results and with measurement. © 1994 John Wiley & Sons, Inc.
Modal control of reflector surfaces using far‐field power measurements
Authors: Silverberg Larry , Washington Gregory 
Published: July 2007

AbstractThe far‐field power received from a transmitting reflector antenna was maximized by varying the shape of the reflector surface. The shape of the reflector surface was controlled by a modal autofocus method which deformed the membrane sequentially into the full range of its natural modes of vibrations. The convergence time was shown to depend on the scan time associated with a natural mode of vibration, the number of cycles the algorithm underwent before convergence, and the desired resolution of the surface shape. A numerical example illustrates the method presented. © 1994 John Wiley & Sons, Inc.
A new broadband circular patch antenna
Authors: Dey Supriyo , Aanandan C. K. , Mohanan P. , Nair K. G. 
Published: July 2007

AbstractA simple technique to improve the impedance bandwidth of a circular microstrip patch antenna using two sectoral slots is proposed. Using this design more than 5% impedance bandwidth is obtained. The added advantage of this new antenna is that it can be fed by a 50‐ω microstrip line. © 1994 John Wiley & Sons, Inc.
Power added efficiency and gain improvement in mesfet amplifiers using an active harmonic loading technique
Authors: Ghannouchi F. M. , Beauregard F. , Kouki A. B. 
Published: July 2007

AbstractA six‐port‐based multiharmonic load‐pull setup is used to characterize a medium‐power MESFET transistor for the design of microwave amplifiers. Complete load‐pull measurements at the fundamental (1.7 GHz) and the second harmonic (3.4 GHz) are obtained for two bias points in class A and AB operation. It is shown that the power gain and the power added efficiency can vary up 0.6 dB and 6%, respectively, as the phase of the second harmonic load is changed. © 1994 John Wiley & Sons, Inc.
Bistatic scattering width evaluation for nonlinear isotropic infinite circular cylinders
Authors: Caorsi S. , Massa A. , Pastorino M. 
Published: July 2007

AbstractThis Letter presents an approximate solution to the problem of computing the bistatic scattering width (BSW) for nonlinear, isotropic, infinite, circular cylinders illuminated by TM waves. An iterative solution is developed for weak nonlinearities of the Kerr type, within some approximations for the internal field. Some preliminary results are reported, which show the effects of some of the quantities involved in the nonlinear process. © 1994 John Wiley & Sons, Inc.
Direct electro‐optic modulation of lightwaves in fiber
Authors: Agili Sedig S. , Koryu Ishii T. 
Published: July 2007

AbstractAn audio modulating electric field is applied to a small section at one end of a relatively long optical fiber. When a He‐He laser beam is guided through the optical fiber, the lightwaves are directly modulated by the modulating electric field and detected at the other end of the fiber. © 1994 John Wiley & Sons, Inc.
An active load‐pull measurement system using two six‐port reflectometers
Authors: Deshours F. , Bergeault E. , Jallet L. , Huyart B. 
Published: July 2007

AbstractThis article presents a microwave active Load‐Pull measurement system, using two wide‐band six‐port junctions in order to have nonlinear characterization of power transistors. Experimental results performed on a 900‐μm MESFET for different operating classes are reported and discussed. © 1994 John Wiley & Sons, Inc.
Microwave correlation temperature of an isothermal lossy material
Authors: Waro Philippe , Leroy Yves 
Published: July 2007

AbstractA microwave correlator is connected to the inputs of an isothermal passive two port made of two antennas placed on both sides of an isothermal lossy material. We verify in which way the output signal of the correlator depends on the scattering matrix of the two port, on the temperature and reference temperature of the radiometer, and on the delay time of the correlator. © 1994 John Wiley & Sons, Inc.
A new compact ring hybrid and its use in a singly balanced mixer
Authors: Nguyen Cam 
Published: July 2007

AbstractA new miniaturized 180—degree ring hybrid was developed. Its circumference is only one wavelength, as compared to the one and a half wavelengths of the conventional ring hybrid. Simple formulas for its scattering (S) parameters along with design information were derived. The obtained S parameters and measured performance of the ring at X band (8–12 GHz) confirm the 180—degree hybrid feature. A microstrip singly balanced diode mixer using the new ring was also developed at X band band with less than 6.5 dB of conversion loss and more than 25 dB of LO‐rf isolation. © 1994 John Wiley & Sons, Inc.
Transverse conduction current and radiation pattern of an arbitrarily shaped symmetrical patch antenna coupled with a director
Authors: Aksas R. , Vorst A. Vander 
Published: July 2007

AbstractWe describe a new model that yields the transverse component of the conduction current as well as the radiation pattern of the cross‐polar component of a multilayered radiating structure. The structure is com‐posed of a microstrip patch antenna with an arbitrary shape, associated with a director having the same shape and the same axes of symmetry. Losses, dispersion, strip thickness and roughness, and edge diffraction are taken into account. Calculated results agree very well with experimental results previously obtained for a circular shape. © 1994 John Wiley & Sons, Inc.