bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electromagnetic Field Measurement
Authors: Kanda Motohisa 
Published: April 2005

Abstract
Various electromagnetic field sensors for measuring radiofrequency (RF) electric and magnetic fields are discussed.
Throughout the discussion, the interplay between measured quantities and predicted (modeled) quantities is emphasized. The ability of measurements and the restrictions imposed by rigorous theoretical analysis of given models are discussed for the frequencies from 10 kHz to 40GHz and upward.
Electromagnetic Wave Scattering
Authors: Musselman Randall L. 
Published: April 2005

AbstractElectromagnetic wave scattering is the reradiation of electromagnetic energy that results when an electromagnetic field encounters an abrupt change in electrical parameters. Typically, this occurs when an electromagnetic field is incident on a structure or scattering object. When the original electromagnetic field crosses the boundary between two regions of different materials, each with different electrical properties, the field will change as it enters the second region. Sources, including conduction, displacement, and polarization currents, will be induced at the discontinuity between the two regions. These currents act as sources of electromagnetic radiation, much like the sources of the original incident electromagnetic field. This reradiation is calledelectromagnetic scatteringbecause it scatters the incident electromagnetic field from its original propagation path.
Electromagnetic Waves in Ionosphere
Authors: Hunsucker Robert D. 
Published: April 2005

AbstractSince the existence of the ionosphere was confirmed in 1925 using radio techniques, we have gained a good understanding of the basic physics and morphology of the solar–terrestrial environment. In this article we summarize the basic physics of the ionosphere and of the interaction of radiowaves with the ionosphere. The fundamental mechanisms of the various radio propagation modes and the effects of solar radiation and noise are described for specific radio services. The principal radio techniques for probing the ionosphere and “frontiers of ionospheric research” are summarized. Three of the principal journals that publish research in the subject of this article areRadio ScienceandJournal of Geophysical Research-Space Physics(published by the American Geophysical Union) andTransactions of the IEEE Group on Antennas and Propagation(published by the Institute of Electrical and Electronic Engineers).
Elliptic Filters
Authors: Noren Kenneth V. , Grimm Jerry Michael 
Published: April 2005

Abstract
This article provides an overview of elliptic filter synthesis for RF and microwave frequencies. The characteristics of an elliptic filter function are discussed and compared to other classical filter function responses. An overview of the mathematics of the lowpass elliptic filter function is discussed. Methods for transforming the low‐pass elliptic function to highpass, bandpass, and band‐reject functions are provide. The article concludes with a discussion of the realizations for RF and microwave elliptic filters and discusses issues related to RF and microwave elliptic filter synthesis.
Feedback Oscillators
Authors: Zhou Jianyi , Hong Wei 
Published: April 2005

AbstractIn this article, the basic theory of feedback oscillators related to balanced condition, startup condition, stability condition, frequency stability, and other characteristics phase noise, is summarized. Typical feedback oscillators, such asLCoscillators,RCoscillators, crystal oscillators, dielectric oscillators, ring oscillators, and voltage‐controlled oscillators, are illustrated.
Ferrite Isolators
Authors: Bayard B. , Sauviac B. , Vincent D. 
Published: April 2005

AbstractSignal processing requires specialized functions, particularly in the microwave range, where wave propagation can easily be corrupted. The main applications of isolators as well as their characteristics are described. Some waveguide and planar microwave ferrite devices based on the Faraday effect, field displacement, or gyroresonance are then reviewed. For a better understanding of the functioning of such devices, microwave properties of ferrite materials are presented. Ferromagnetic resonance and the resulting nonreciprocal effects are also explained. Finally, more recent developments in the use of hard ferrites and in magnetic films technology are discussed.
Microwave Ferroelectric Devices
Authors: Patel D. P. , Pond J. M. , Rao J. B. L. 
Published: April 2005

AbstractControl of reactance in microwave circuits, devices, and systems is a common method by which the response of a microwave circuit such as a filter, resonator, or phase shifter can be tuned. Devices based on a class of voltagedependent non‐linear dielectrics known as ferroelectrics provide an alternative to semiconductor varactor diodes and ferrimagnetic components, which are the most common devices of this type.This article describes microwave devices that exploit the variation of the ferroelectric's permittivity with applied DC electric field. The main feature of these “tunable” microwave devices is the change of their capacitance, impedance, or phase velocity. We will describe varactors, oscillators, tunable filters, and phase shifting devices.
Ferroelectric Materials
Authors: Pandey R. K. 
Published: April 2005

AbstractThe interplay between the forces of electric field, mechanical stress, and temperature in a material can cause a host of effects and properties to evolve. Ferroelectricity is one of these fascinating phenomena, acquired by some dielectric materials, originating from the interactions between the three natural forces. For ferroelectricity to exist, the fundamental condition of noncentrosymmetry of a crystal unit cell must be satisfied. For this and some other reasons, ferroelectricity without exception coexists in materials that are simultaneously piezoelectrics and pyroelectrics. Thus all ferroelectrics are good examples of multifunctional materials. Their multifunctional nature makes them extremely attractive for a host of applications ranging from classical to ultramodern. This article attempts to explain the complex but very interesting properties of ferroelectric materials and their counterparts such as piezoelectrics and pyroelectrics. Phenomena such aspyrooptic effectandmultiferroicmaterials, which are rarely covered in a discussion of ferroelectricity, are also briefly discussed. Processing of ferroelectric materials and their applications have also been included in the discussion with the hope that they will prepare interested readers for more advanced studies of this vast subject.
Filter Theory
Authors: Görür Adnan 
Published: April 2005

Abstract
The main categories of filters are defined in terms of the general response types of lowpass, bandpass, highpass, and bandstop. The basic concepts of filters including transfer function, insertion loss, return loss, phase delay and group delay, are described. Filter characteristics such as maximally flat or Butterworth, equally ripple or Chebyshev, elliptic function, generalized Chebyshev or pseudoelliptic, and maximally flat time delay are discussed in terms of the poles of transfer function. Two‐port lumped‐element lowpass prototype networks and their element values and filter transformations are given. Richards’ transformation and Kuroda's transformations (or identities), impedance, and admittance inverters are also investigated, which are required for transforming lumped elements to transmission‐line sections, for separating physically filter elements and changing impractical elements into more realizable elements in a filter network.
Fractal Shaped Antennas: A Review
Authors: Anguera Jaume , Puente Carles , Borja Carmen , Soler Jordi 
Published: April 2005

AbstractThe combination of fractal geometry with electromagnetic theory opens an interesting window for research to find new antenna designs and applications. Fractal technology applications can be divided into six main groups: (1) multifrequency antenna elements, frequency‐selective surfaces, and arrays; (2) electrically small antennas; (3) high‐directivity radiating elements; (4) low‐sidelobe arrays; (5) undersampled arrays; and (6) fast computational methods. This article reviews most of the work done in the fractal technology field covering the last six fields.
Frequency Modulation
Authors: Fertig L. B. , Mc Clellan J. H. 
Published: April 2005

AbstractIn this article, concepts relating to instantaneous frequency, along with algorithms for its computation, are reviewed. First, several means by which instantaneous frequency is commonly defined are discussed, and the relationships between instantaneous frequency and time–frequency distributions are explored. Next, several measures of performance commonly used to evaluate instantaneous frequency algorithms, such as the Cramer–Rao lower bound, are examined. Finally, a number of algorithms that have been suggested for IFE are summarized. Despite the relative maturity of frequency modulation in the field of radiocommunications, the field of IFE is a growing one, and one in which research is still quite active.
Frequency Selective Surfaces
Authors: Wu Te-Kao 
Published: April 2005

AbstractA detailed description of frequency‐selective surface (FSS) is provided. Subjects covered include various kinds of FSS and characteristics, bandpass and bandstop FSS, aperture and patch element FSS, thin/thick‐screen FSS, FSS analysis techniques and design tools, dielectric loading effects, grating lobe and Woods anomaly, as well as FSS applications. An FSS bibliography is also provided listing all the references necessary for further research on the subject of FSS.
Frequency Stability
Authors: Howe David A. 
Published: April 2005

AbstractRadio navigation, digital signal processing, photonics, high‐speed communications, and numerous other important systems require a high degree of frequency stability in a variety of oscillators used to “clock” or time the electronic circuits. This article reviews definitions of frequency stability and methods of measuring the frequency stability of oscillators. Physical interpretations of common noise processes are discussed. The equipment and setup for stability measurements are outlined. Examples and typical stability results are presented.
Frequency Synthesizers
Authors: Goldberg Bar-Giora 
Published: April 2005

Abstract
Traditionally, frequency synthesis (FS) generated a single tone with variable frequency or amplitude. There are new applications, especially for testing and simulation, that require multitone generation and even arbitrary wave generation, which relate to digital frequency synthesis. Since the late 1970s, FS has evolved from mainly analog to a mix of analog, radiofrequency (RF), digital, and digital signal processing (DSP) technologies.
Friis Free‐Space Transmission Formula
Authors: Levis Curt A. 
Published: April 2005

Abstract
The Friis transformation formula predicts the power available at the terminals of a receiving antenna due to the power applied to a transmitting antenna when the two are well separated. It is often given in logarithmic form, using decibels. It is assumed that the transmission occurs in free space, that the separation is sufficient to satisfy the far‐field criterion for antennas, and that the antennas are matched in polarization (i.e., the polarization of the receiving antenna is optimum for the polarization of the transmitted wave).
The formula, first published by Harald T. Eriis in 1946, is easily derivable from basic physical principles.
Generalized Scattering Matrix Technique
Authors: Monorchio Agostino , Mittra Raj , Manara Giuliano 
Published: April 2005

AbstractThe generalized scattering matrix (GSM) technique, which is a convenient method for analyzing complex microwave devices, consisting of separable and longitudinally uniform waveguiding structures, is presented in this article. GSM differs from the conventional scattering matrix used in circuit theory or microwave network theory in that it is extended to consider evanescent as well as propagating modes in each waveguide. Some numerical examples are provided to illustrate the importance of the inclusion of higher‐order modes for generating accurate solutions of waveguide discontinuity problems.
Green's Function Methods
Authors: Jin Jian-Ming , Chew Weng Cho 
Published: April 2005

Abstract
The Greens function method is a powerful techniques for solving boundary value problems. Greens function was named after George Green (17931841), who developed a general method to obtain solutions of Poissons equation in potential theory. This method was described in an essay by Green entitled “On the application of mathematical analysis to the theories of electricity and magnetism,” published in 1828.
Ground Penetrating Radar
Authors: Daniels David J. 
Published: April 2005

AbstractGround penetrating radar (GPR) is a nondestructive measurement technique, which uses electromagnetic waves to locate targets or interfaces buried within a visually opaque substance or Earth material. GPR is also termedground probing,surface penetrating(SPR), or subsurface radar. A GPR transmits a regular sequence of low‐power packets of electromagnetic energy into the material or ground, and receives and detects the weak reflected signal from the buried target. The buried target can be a conductor, a dielectric, or combinations of both. There are now a number of commercially available equipments, and the technique is gradually developing in scope and capability. GPR has also been used successfully to provide forensic information in the course of criminal investigations, detect buried mines, survey roads, detect utilities, measure geophysical strata, and in other applications.
Gunn or Transferred‐Electron Devices and Circuits
Authors: Eisele Heribert 
Published: April 2005

AbstractTransferred‐electron devices are the only microwave devices whose operation is based solely on the bulk‐material properties of semiconductors such as GaAs or InP. These devices are employed mainly in low‐noise medium‐power oscillators up to high‐millimeter‐wave frequencies. James B. Gunn was the first scientist to observe the underlying physical phenomenon in an experiment and, therefore, these devices are often referred to asGunn devices. This article describes the principles of operation, basic fabrication technologies, and common oscillator circuits for them. Different device structures for performance optimization and optimization procedures and simulation tools are discussed. The article also summarizes the current state of the art of Gunn devices and the outlook covers the prospects of more recent device structures and material systems.
Helmholtz Equations
Authors: Kowalczyk Piotr , Mrozowski Michal 
Published: April 2005

AbstractScalar and vector Helmholtz equations and their applications in electromagnetics are discussed. Relevance of the Helmholtz equation to wave motion is explained. Derivation involving Maxwell's equations and auxiliary scalar and vector potentials is presented. Basic analytical solution techniques for homogeneous and nonhomogeneous cases are introduced and illustrated in simple problems such as guided waves and radiation from a finite‐length dipole. Numerical methods and the operator approach to investigation of the Helmholtz equation are briefly outlined.
Heterojunction Bipolar Transistor
Authors: Prasad Jayasimha 
Published: April 2005

AbstractThe major advances in heterojunction bipolar transistor (HBT) technology since the mid‐1980s is covered in this article. The cutoff frequency (fT) and the maximum oscillation frequency (fmax) have reached record highs. Indium phosphide (InP) HBTs have shown (fT) and (fmax) in excess of 450 GHz and gate delays of 1.95 ps. Silicon–germanium (SiGe) HBTs have demonstrated 350 GHz (fT) and gate delays of 3.6 ps. The improved performance of the devices has resulted in impressive circuit results. Static frequency dividers operating at 152 GHz has been reported in InP HBT technology. SiGe HBT technology has demonstrated dynamic frequency dividers running at 110 GHz. Multiplexer/demultiplexer (MUX/DMUX) circuits operating at 40 Gbps (gigabits per second) were demonstrated with InP HBTs. On the other hand, 50‐Gbps 4–1 MUX/DMUX circuits have been shown with SiGe HBTs.
Heterostructures Devices
Authors: Ryzhii Victor 
Published: April 2005

AbstractHeterostructures are the elements of many of the most advanced semiconductor devices currently being developed open and fabricated. They are essential parts of modern optoelectronic devices, such as semiconductor lasers, lightemitting diodes, and photodetectors with highest performance. Heterostructures are being employed increasingly in high‐speed digital and high‐frequency analog devices. The advantages of heterostructures are that they provide effective control over the states and motions of charge carriers—electrons and holes in active regions of heterostructure‐based devices.
High‐Field Effects
Authors: Hess K. 
Published: April 2005

AbstractElectrons and holes contribute to the charge transport in semiconductors, while ordinary charge transport in metals is restricted to electrons only. Another distinctive feature of semiconductor transport is its inherent nonlinearity in high electric fields.The basic phenomena of high field transport are nonlinear conductance; changed responses to magnetic fields; changed high‐frequency response, including the dielectric function; and changed confinement in potential wells or at heterojunctions between different semiconductors.
HTS Film Growth
Authors: Char Kookrin , Matijasevic Vladimir 
Published: April 2005

Abstract
In the decade since the discovery of high‐temperature superconductivity (HTS) in cuprate compounds, thin‐film materials have played an important role in the evolution of this field. The discovery of HTS has led to a rapid development of many different thin film deposition techniques. HTS thin films are now routinely made in hundreds of laboratories around the world, and thin‐film research is actively pursued in areas such as new superconducting materials and epitaxial oxide heterostructures. More recently, advances in deposition processes have brought about the synthesis of larger‐area HTS films, making fabrication less expensive and allowing for high‐throughput manufacturing of single‐superconducting‐layer films.
In this article, we review the physical vapor deposition (PVD) techniques most frequently used for HTS thin‐film synthesis.
History of Wireless Communication
Authors: Leggatt Patt 
Published: April 2005

Abstract
Beginning with the discoveries of Michael Faraday and then examining the work of the Maxwellians, Lodge, Fitzgerald, Heaviside, Hertz, Edison, Armstrong, and others, the history of wireless communications from 1831 to 1915 is presented. The article leaves off with Armstrong in 1915, whose triode oscillator paved the way for modern electronics and specifically wireless devices.
Indium Phosphide (InP)
Authors: Wada Osamu 
Published: April 2005

AbstractIndium phosphide (InP) and InP‐based compound semiconductors grown on InP substrates are extremely important for the application to high‐speed, microwave, and optoelectronic devices. In the following, general properties of InP‐based materials and heterostructures are described first, and state‐of‐the‐art device and integrated circuit technologies for both electronic and optical systems are reviewed. High‐speed digital and microwave transistors such as high‐electron‐mobility transistors (HEMTs), heterojunction bipolar transistors (HBTs), and their integrated circuits have been developed for digital signal processing, including optical communications with the bit rate of 40–100 Gbps. Microwave devices for system applications in the frequency range up to 200 GHz are introduced. Long‐wavelength lasers and photodetectors, which are key in current optical communication networks, would have not become real without InP‐based compound materials covering the appropriate energy gap. Optoelectronic devices, including lasers, optical modulators, photodetectors, and their optoelectronic and photonic integrated circuits (OEICs and PICs) developed for bit rates up to 40 Gbps, are reviewed. Also, all‐optical devices being developed for the application to systems beyond 100 Gbps are described, which includes mode‐locked lasers and ultrafast all‐optical optical switches based on unique ultrafast properties of InP‐based materials.
Integro‐Differential Equations
Authors: Garcia Manuel 
Published: April 2005

AbstractThis article discusses a variety of methods and approximations used to solve and calculate integrodifferential equations, with emphasis, is on the utilitarian rather than the theoritical. Integrodifferential equations can describe linear and nonlinear systems that have memory, or are not in equilibrium. The appearance of both derivatives and integrals in an equation (e.g., expressing some type of balance with respect to time) means that instantaneous rates (e.g., velocity) and accumulated history (e.g., metal fatigue) determine the state of the system at the present moment. It is this aspect of integrodifferential equations that gives them their intellectual appeal, wide applicability, and challenging nature.
Intermodulation Measurement
Authors: Taher Abuelma’atti Muhammad 
Published: April 2005

AbstractWhenever a number of signals of differing frequencies pass through a nonlinear device, energy is transferred to frequencies that are sums and differences of the original frequencies, that is, intermodulation products. Using a Taylor series expansion, this article presents a simple intermodulation theory and discusses its limitations and extensions. Methods of characterizing and measuring the intermodulation performance of nonlinear devices are presented, and their merits and demerits are discussed.
Iterative Methods
Authors: Burkholder Robert J. , Lee Jin‐Fa 
Published: April 2005

Abstract
Iterative solution algorithms are described for complex systems with a large number of degrees of freedom. Areas of application include partial differential equations, integral equations, and hybrid methods in electromagnetics. Classical (or stationary) methods and conjugate gradient (nonstationary) methods are presented. Classical methods are generalized in terms of matrix splittings. The conjugate gradient method is derived in detail from the point of view of Galerkin testing and Krylov spaces. Preconditioning is discussed, and some common preconditioners from classical methods are presented.
Leaky Wave Antennas
Authors: Galli Alessandro , Frezza Fabrizio , Lampariello Paolo 
Published: April 2005

AbstractThe basic radiative features, operation, design, and realization procedures of leaky‐wave antennas for microwave applications are described. The relations between the propagation properties of open waveguides, on which these antennas are based, and the relevant radiation patterns are discussed, exploiting the leaky‐wave concept. The main radiative characteristics (scanning behavior, beamshaping, etc.) are presented, and the procedures for analysis and synthesis are outlined. Examples of proposed structures are reported, and accounts for practical operation and measurements are given.
Lens Antennas
Authors: Malherbe J. A. G. 
Published: April 2005

AbstractLenses can be employed to act as high‐gain scannable antennas. The optical principles that apply to lens antennas are discussed, as well as the materials used in the construction of lenses. The basic lens function is discussed, and examples given of simple planoconvex and planoconcave lenses, together with the equations that describe the lens surfaces. In order to reduce the lens size, lenses are zoned, and equations for lens zoning are given. Other lens parameters such as gain, sidelobe level, reflections, loss, and bandwidth are treated. Lens systems for scannable or multibeam antennas are described, and design and analysis procedures for Rotman lenses given. Other lenses discussed include Luneburg,R‐2R, integrated dielectric, and Fresnel zone lenses.