bluuebunny/crossref_metadata_2025_split huggingface dataset:
Surface Acoustic Wave Devices
Authors: Morgan D. P. 
Published: April 2005

AbstractA surface‐acoustic‐wave (SAW) device employs an acoustic wave guided along the surface of a piezoelectric crystal, in which the stresses and strains of the wave are coupled to electric fields. The wave has a low velocity, typically 3500 m/s, and propagates with low attenuation. These features enable compact low‐loss devices to be developed for electronics applications at frequencies up to several gigahertz. Arrays of metal electrodes are used to generate, detect, or reflect the waves. This technology has enormous versatility because standard lithographic techniques can be used to fabricate almost arbitrary geometries.This article summarizes the nature of surface waves and some relevant propagation effects, including diffraction. The interdigital transducer, used in all these devices for wave generation, is described. A survey of suitable materials is given, including quartz, lithium niobate, and lithium tantalate. Transversal bandpass filters are weighted using apodisation or withdrawal weighting. They are widely used in TV receivers, as well as in professional equipment which calls for very high‐performance devices. For radar, SAW pulse compression filters perform a correlation operation, increasing the range capability. Other devices perform correlation for spread‐spectrum communication waveforms; an example is the SAW nonlinear convolver, which is capable of instantaneous programmability. For mobile telephony there has been a strong demand for miniature low‐loss bandpass filters, and a wide variety of novel SAW devices have been developed. For example, impedance element filters give 1 dB loss at 900 MHz, with 30 MHz bandwidth and a package size of 2×2 mm2. For IF CDMA filters, a modified form of the transversal filter, called the R‐SPUDT (resonant single‐phase unidirectional transducer), enables both low loss and small size to be obtained. For GSM IF circuits, transverse‐coupled resonator filters have been developed to give a very narrow bandwidth of 200 kHz.The article concludes with a superficial survey of the theory of these devices.
Surface Mount Technology
Authors: Trybula Walter J. , Trybula Michael 
Published: April 2005

Abstract

Surface mount assembly (SMA) is the description of a technology that incorporates the electrical and mechanical of components to printed wiring boards (PWBs) or a similar type of circuit substrate. The term
surface mount
comes from the methodology of attaching the components.

Many categories of packages can be employed in surface mount assembly. They can be identified into two categories: leadless devices and leaded chip carriers.
Electromagnetic Surface Waves
Authors: Wu Zhipeng 
Published: April 2005

AbstractIn this article, the electromagnetic surface waves propagating along an interface between two dielectric media or an interface between air and a multilayered structure in planar, cylindrical, and spherical geometries are introduced. Specific surface waves considered are (1) the Zenneck surface wave, (2) the surface wave on a conductor‐backed dielectric slab, (3) the radial cylindrical surface wave on a flat surface, (4) the axial cylindrical surface wave, (5) the surface wave on a dielectric‐coated conducting cylindrical, (6) Norton and trapped surface waves on flat ground interface, (7) surface‐wave propagation over an inhomogeneous flat surface, and (8) surface‐wave propagation over a spherical ground. Several examples are given to illustrate the propagation of surface waves in these geometric structures. The surface waves propagating along Earth's surface have been used for wireless communications and remote sensing. On the other hand, the surface waves on conductor‐backed dielectric slabs become a problem in microwave printed circuits and microstrip antenna systems. The understanding and control of surface waves are therefore important in radio systems.
Television and FM Broadcasting Antennas
Authors: Bendov O. 
Published: April 2005

Abstract
Antennas for television and FM broadcasting are usually installed on tall towers to maximize the service area. A high‐power transmitter feeds the broadcast antenna to provide “passable” picture and sound at distances approaching 70 m. In the UHF range (TV channels 14 to 69), the transmitter's peak power could be as high as 280kW. In the VHF range (TV channels 2 to 13 and FM), a transmitter's peak power of 70kW is not unusual. In addition to high power‐handling capability, broadcast antennas must continue to perform under severe weather conditions, such as ice storms and hurricane winds. Antennas, especially for television broadcasting, must be designed to accept and radiate all of the power delivered by the transmitter. Antennas for digital television must be designed to meet more stringent specifications than those for antennas for analog television.
Thermal Analysis and Design of Electronic Systems
Authors: Kraus Allan D. , Bar-Cohen Avram , Geisler Karl J. 
Published: April 2005

AbstractThe challenges posed by high chip heat fluxes and ever more stringent performance and reliability constraints make thermal management a key enabling technology in the development of microelectronic systems for the twenty‐first century. Thus, thermal packaging efforts must be performed in the context of the salient trends and parameters that characterize the IC technology and the electronic products industry.Recent road‐mapping efforts, have affirmed the expectation that improvements in CMOS semiconductor technology will continue unabated into the early part of the twenty‐first century. Exploiting the potential of this IC technology, with the attendant increase in chip size, switching speed, and transistor density, will necessitate significant improvements in packaging technology.
Thin Films
Authors: Wasa Kiyotaka , Setsune Kentaro 
Published: April 2005

AbstractThin film ferroelectric materials and hexagonal piezoelectric materials are essential for fabrication of electronic and/or photonic devices. Ferroelectric materials are dielectrics that have a spontaneous polarization with nonlinear hysteretic properties and show several unique properties including high dielectric permittivity, high piezoelectricity, high pyroelectricity, and high electrooptic characteristics. Thin film ferroelectric materials have a high potential for miniaturization and/or integration with the semiconductive devices. Thin films are also important to the understanding of ferroelectricity. Thin films are commonly fabricated by depositing individual atoms on a substrate. The film thickness is typically less than several micrometers.
Thin Film Resistors
Authors: Collins F. M. , Anderson W. A. , Ma E. M. 
Published: April 2005

AbstractIn this article, we will discuss the historical background and technological evolution of thin film resistors. We will also review resistor technology design concepts, including requirements for (1) the range of resistance values, (2) their precision, and (3) the physical size in terms of power or voltage demands, materials used in production, finished formats, performance characteristics, and some advantages of integrated thin film resistor production.
Transient Analysis
Authors: Feely Orla , Mulkeen Brian 
Published: April 2005

Abstract
This article reviews the basic principles of transient circuit analysis, which is a long‐established branch of circuit theory with a wide range of applications. It examines transient behavior in linear circuits and explains the type of behavior that can occur in these circuits. It shows how this behavior can be analysed by solving appropriate differential equations, or by applying the Laplace or Fourier transform. Application of the Laplace transform to distributed circuits is also considered.
Transmission Lines and Parameters
Authors: Chen Ji , Chen Richard L. 
Published: April 2005

Abstract
Transmission lines are defined as waveguiding structures that can support transverse electromagnetic (TEM) waves or quasi‐TEM waves. This article concentrates on five commonly used transmission‐line structures. The transmission‐line parameters are first introduced in the derivation of the telegrapher's equations by dividing the transmission line into electrically small segments that can be described by the lumped‐element circuit theory. The transmission‐line parameters are then derived from rigorous electromagnetic field analysis. Five commonly used transmission lines—parallel‐plate waveguides, coaxial cables, two‐wire lines, striplines, and microstrip lines—are presented, and the techniques used to extract their corresponding transmission‐line parameters are given. A common integrated circuit (IC)‐level transmission‐line structure is presented, and the challenges in parameter extraction for future micro‐ and nanoscale transmission lines are also discussed.
Traveling Wave Antennas
Authors: Waterhouse Rod B. 
Published: April 2005

AbstractIn this article, a review of common traveling wave antennas is presented. We briefly discuss the structural characteristics, design trends, and overall performance of several traveling wave antennas including Beverage antennas (wire and printed), horn antennas, reflectors, and tapered slots. Some examples of manufactured traveling wave antennas are given. We also attempt to outline the fundamental properties of this general class of antenna and how it can be differentiated from resonant style radiators. It will be shown that traveling wave antennas are essential for a variety of applications ranging from sophisticated radio astronomy platforms to simple low‐frequency communications.
Tunnel Devices
Authors: Sargent Edward H. , Xu J. M. 
Published: April 2005

AbstractTunnel devices take advantage of the wave‐like properties of charge carriers in implementing a desired function. The term tunneling refers to the movement of matter from one side of an energetic barrier to the other even though it does not possess sufficient energy to overcome the potential barrier according to the laws of classical mechanics. Instead, the quantum‐mechanical wave function of the particle penetrates inside the barrier and extends into the medium on the far side. Tunnel devices typically possess nonlinear, nonmonotonic current‐voltage characteristics and are characterized by very rapid fundamental propagation times. They find application in such diverse areas as microwave oscillators; multiple‐level logic, switches, memory elements; and lasers.
Variable‐Frequency Oscillators
Authors: Gutierrez Germán 
Published: April 2005

AbstractOscillators are abundant around us. Most oscillators are of two basic kinds: sinusoidal and relaxation. This article covers the main topologies for all popular oscillators and the ways to make their frequency of oscillation variable. The description is independent of frequency and can be applied from very‐low‐frequency to microwave oscillators. Mechanical examples give a very simple explanation for the mechanism of oscillators and the concept of resonance.
Very High Frequency Range
Authors: Campbell Richard L. 
Published: April 2005

Abstract
The Very High Frequency (VHF) range extends from 30MHz to 300 MHz, which means that when a VHF sine‐wave signal is observed on an oscilloscope, the trace completes from 30 to 300 million cycles each second. The wavelength and frequency of VHF signals has a profound impact on the hardware we build to use these frequencies. The 30 to 300MHz frequency range has been popular since radio engineers first discovered how to reliably generate and amplify VHF signals during the 1930s. The VHF range has significant advantages for some common applications over higher and lower frequency ranges.
Voltage‐To‐Frequency Converters
Authors: Vidal-VerdÚ Fernando , Navas-GonzÁlez Rafael , Rodriguez-VÁzquez Angel 
Published: April 2005

AbstractVoltage‐to‐frequency‐converters (VFCs) do typically employ relaxation oscillators to generate an output signal whose frequency depends linearly on an input voltage. VFCs are data converters; they are designed to codify the input voltage by means of the output frequency. Hence, they have strong requirements regarding linearity, dynamic range, and stability. On the other hand, compared to other converters, they have the advantage of low cost, particularly for large resolutions; 13 bit resolution is typical, and more than 20 bits are feasible. However, in such a case several milliseconds may be necessary to complete the conversion—the smaller the resolution, the shorter the conversion time.The serial frequency modulated output provided by VFCs is particularly well suited for telemetry, to send the outcome of a measurement by wire, radio, or fiberoptic links. After the frequency‐modulated signal is received, it can be easily codified into a digital word, or converted back into a voltage by a frequency‐to‐voltage converter. This type of output simplifies galvanic isolation through the use of either an optocoupler or a magnetic coupler. The serial output is also useful for increasing system compactness if throughput requirements are not high. Although many smart monolithic sensors have serial frequency‐modulated outputs, a VFC is needed in case we have an output voltage like that of a Wheatstone bridge after being amplified by an instrumentation amplifier, or the output of a generating sensor such as a thermocouple.This article deals first with the concepts behind voltage to frequency conversion, and then describes the main types of VFCs on the market, their limitations and main applications. Frequency‐to‐voltage converters are also briefly described.
Waveguide Discontinuities
Authors: Sorrentino R. , Alimenti F. 
Published: April 2005

AbstractThis article deals with waveguide discontinuities that are unavoidably present in any microwave circuit either unintentionally or to the purpose of performing a prescribed function. After a brief introduction, this contribution illustrates the basic theory behind the modal analysis of such structures and their general properties. Finally a categorization of waveguide discontinuity is proposed with reference to some geometric characteristics that are related to the corresponding electromagnetic problem.
Wireless Communication Systems
Authors: Armada Ana García , Ramos López Javier , González Serrano Francisco J. 
Published: April 2005

AbstractThis article introduces wireless communications systems and explains the different products and standards related to wireless communications. The article is divided into five main sections.A brief introduction in Section 1 offers a perspective of the evolution of wireless communications systems and introduces a useful classification. After this introduction, Section 2 is devoted to the explanation of basic concepts and fundamentals of the different wireless products, while Section 3 explains the related technology.Sections 2 and 3 both make it easy to understand Section 4, in which five wireless products and related standards are detailed: cellular, cordless, trunking, paging, WLAN, and WPAN systems.Finally, Section 5 offers a brief vision of the future evolution of wireless systems, introducing advanced technologies such as “smart” antennas and spacetime transmission diversity (STTD), and research, towards the fourth generation of mobile communications.
Calibration of a Circular Loop Antenna
Authors: Aykan Aydin 
Published: April 2005

Abstract

The calibration of a measuring loop antenna means assigning an antenna factor
K
for each frequency in the entire measurement band. This factor can be found either by calculating the impedance of the loop or by using a well‐defined standard magnetic field of a transmitting antenna. For both methods, it is necessary to obtain an accurate relation between the magnetic field and the geometric dimensions of the loops. Generally, a manufactured loop has a complex geometric shape with complex electrical behavior so that its impedance cannot be accurately determined analytically. In such cases, the standard magnetic field method remains as the only alternative for calibration. The formulas needed for implementation of the method, which takes into account the dimensions of the loops with finite conductor radii as well as the current distribution along the loop, are given. With the procedure presented here, the calibration is reduced to an accurate measurement of attenuation.
Corrugated Horn Antennas
Authors: Lucci L. , Pelosi G. , Selleri S. , Nesti R. 
Published: April 2005

AbstractIn this work the basic theory of circular corrugated horn antennas is presented, using easy concepts with simple mathematics. The aim is to give the reader an understanding of the fundamental electromagnetic properties of these devices and to provide a set of quantitative design tools for the electromagnetic engineer.The wave propagation problem in corrugated waveguides is approached by approximating the field boundary conditions on the corrugation limit surface and by making further assumptions, suggested by practical considerations, with a consequent mathematical simplification of the theory. This approach has the major advantage of providing an analytical solution for the electromagnetic field, which is accurate as far as the approximate boundary conditions are valid and that enables us to highlight the most relevant features of corrugated waveguides.The problem of radiation from corrugated horns is addressed in a similar way by choosing an approximated model sufficiently accurate for almost all practical needs. This model, the “Gaussian beam model,” has a simple analytical formulation and is rigorously treated. The final result of this approach is a set of analytical formulas relating electromagnetic properties to geometric parameters that are very useful in the design.Then, further design aspects concerning the throat region, the phase center, and cross‐polarization are introduced and a numerical methods for highly accurate analysis of corrugated horns are described, ending with some design examples.
Reconfigurable Antennas
Authors: Bernhard Jennifer T. 
Published: April 2005

AbstractHigh‐speed wireless systems of the future will require more functionality from antennas than can be provided by classic designs. One approach to this challenge is to develop reconfigurable antennas. The goal of a reconfigurable antenna—one that can adjust its operating frequency, bandwidth, and/or radiation pattern to accommodate changing system requirements—poses significant challenges to both antenna and systems designers. This article first defines antenna reconfigurability and then highlights some of the more recent advances in the area of antenna reconfiguration. Additionally, some of the barriers that still need to be overcome to arrive at realizable technologies are discussed. These barriers include the development of reliable, mass‐manufacturable radiofrequency microelectromechanical system (RF MEMS) switches, the design of switch bias networks that will not interfere with antenna operation, and the expansion of signal processing and feedback algorithms to fully exploit this new antenna functionality.
Reflectarray Antenna
Authors: Huang John 
Published: April 2005

AbstractThis article gives an overview of the development history and key design methodologies for the reflectarray antenna, in particular the printed reflectarray. A reflectarray is an array antenna similar to a parabolic reflector, but with its reflecting surface capable of being designed either flat or slightly curved. On the reflecting surface, there are many isolated (not physically combined by power division lines) antenna elements, which are illuminated by a feed antenna located at the vicinity of a focal point. These isolated elements are each predesigned with a particular electrical phase delay to compensate for the phase differences due to different pathlengths from the feed. The illuminating electrical field from the feed will then be scattered from these isolated elements and form a cophasal concentrated beam in the far‐field distance.
Multimode Equivalent Network Representations
Authors: Guglielmi Marco 
Published: April 2005

AbstractThe objective of this article is to describe the formulation of multimode equivalent network representations of waveguide junctions. Both planar and arbitrary junctions are discussed, thereby covering essentially all possible cases of engineering interest for microwave and millimeter‐wave applications. The theory presented in this article effectively transforms complex field problems into linear algebraic problems of simple solution. The theory described is rigorous and computationally very efficient and can therefore be used as a very solid theoretical frame for the development of advanced full‐wave electromagnetic simulation computer programs. In addition to theory, a number of applications are also demonstrated showing very good agreement between measured and simulated performances, thereby fully validating the theory presented.
Microwave Detectors
Authors: Ham Ronald E. 
Published: April 2005

Abstract
Microwave detectors generally measure power in the controlled impedance environments afforded by transmission lines and waveguides. The system impedance is known, so voltage and current magnitudes can be derived. With the judicious application of other microwave components such as power splitters and quadrature couplers, phase information can be extracted from multiple power measurements; therefore, full characterization of a system or component is possible with only the microwave detector to convert microwave signal characteristics to the readily observable and measurable quantities of low‐frequency voltages and currents.
Microwave detectors sense the amplitude or power of a signal, or the change in the amplitude or power of a signal. They are used for the determination of signal power level and for recovery of information placed upon the microwave signal amplitude.
Small Antennas
Authors: Fujimoto Kyohei 
Published: April 2005

AbstractSmall antennas are categorized into four types.Electrically Small Antenna (ESA), Physically Small Antenna (PSA), Physically Constrained Small Antenna (PCSA), and Functionally Small Antenna (FSA). Although one uses four categories, the classification is not necessarily distinct, so that one class of antenna can be classified into more than one class; for instance, when a patch antenna has the edge (radiating aperture) of one‐fifth wavelength in its peripheral, the antenna is referred to as both ESA and PCSA.Two major subjects exist in small antennas: (1) investigation of characteristics and performance of small antennas, and (2) exploitation of methods to attain small antenna, particularly ESA.
Integrated Antenna Systems
Authors: Fujimoto Kyohei 
Published: April 2005

AbstractAn antenna system is ordinarily designed independently from transmitter or receiver circuitry, to which the antenna is connected by a transmission line. Unlike such an ordinary antenna system, an integrated antenna system (IAS) incorporates components, either passive, active, or both, into the antenna structure. The term integration here implies unification of an antenna and device or circuitry so that the performance of the antenna system is determined by both the antenna and the integrated device or circuitry. By means of integration, one can expect either improvement or modification of the antenna characteristics, or enhancement of antenna performance due to the addition of functions introduced by the integration.
Antennas for Mobile Communications
Authors: Fujimoto Kyohei 
Published: April 2005

AbstractAntennas used for mobile communications are not necessarily specialized types of antenna; ordinary antenna types can be used. However, there are several distinctions in performance between mobile and fixed communications with respect to design methodology for antennas in mobile communications, including variations of field strength, varied environmental conditions, mechanical and physical robustness, and mechanical and electrical system performance.