bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ring Resonators and Circuits
Authors: Hsieh Lung-Hwa , Chang Kai 
Published: April 2005

Abstract
Because of their advantages of low cost and easy fabrication, ring resonators are used in many applications such as filters, oscillators, mixers, baluns, hybrids, magic Ts, couplers, and antennas. In addition, they have been successfully used to measure the phase velocity and dispersion of a microstrip line. This article explains the basic field and circuit model analyses that can be used to investigate the characteristics of a ring resonator. On the basis of these analyses, ring resonators can be implemented and designed for different devices. The simple structure and high performance of a ring circuit fulfill the highly desired requirements of many modern wireless systems and other applications.
Schottky Barriers
Authors: Ashok S. 
Published: April 2005

Abstract
The Schottky barrier, one of the earliest and simplest semiconductor interfaces studied, consists of a metal in contact with a semiconductor.
The silicide Schottky barriers are of interest from both fundamental and practical viewpoints, as the MS interface here is buried inside the semiconductor bulk, thus obviating the deleterious influence of surface oxides and other contamination.
We will consider here two basic models, the earlier one due to Schottky and the later one inspired by Bardeen's postulation of the surface states.
Sky Wave Propagation at Low Frequencies
Authors: Johler J. Ralph 
Published: April 2005

AbstractAlthough LF sky waves have been used since the earliest days of radio science, vigorous study of these waves occurred mainly between 1950 and 1970. This research was in large measure a consequence of the development of precision pulsed ground‐wave radio navigation and positioning systems. Although the ground wave is very stable with time of day, season, and so on, the ionospheric waves vary with time, and if such waves were not somehow sidestepped, the accuracy and precision of the navigation or positioning system would deteriorate. Thus, from an engineering point of view, LF sky waves were a problem in developing navigation systems such as Loran‐C or Loran‐D. One direct consequence of this research was the development of the wave hop theory of LF sky wave propagation, which will be introduced here.
Slow Wave Structures
Authors: Wu Ke 
Published: April 2005

AbstractThe slow wave is a particular type of wave propagation, usually of the guided‐wave type, and it is described mostly in the frequency‐domain. Slow‐wave structures are wave‐guides or transmission lines in which the wave travels with a phase velocity equal to or less than a certain predesignated velocity of wave propagation. In other words, the slow wave should be interpreted relative to its fast‐wave counterpart compared with a velocity of reference, such as the speed of light in a hollow metallic waveguide. In this description, the slow‐ and fast‐wave‐guiding properties are simply characterized by a popular technical term called the effective permittivity, which may involve the effect of permeability if the relative permeability is not equal to one, even though the concept of a separate effective permeability is valid.
SPICE
Authors: Morong William H. 
Published: April 2005

Abstract
SPICE is a program for component‐level electronic simulation, primarily directed toward analog circuits. SPICE processes a “net list” comprising the unique interconnections of named components with numbered terminals, calculating their interactions in accordance with fundamental electrical laws. Modern SPICE applications include a graphical user interface for schematic entry and for plotting results. SPICE
applications often include provisions for sharing input and output with other programs. SPICE applications are available both by purchase and as “freeware” for download or for Internet use at vendors’ sites. SPICE includes basic components, such as resistors and reactive components, sources, both independent and dependent and the ability to process models of semiconductor devices. Devices cannot be processed as models or including aggregations of models and other components can be processed as subcircuits. Components, models, and subcircuits are usually kept in local SPICE libraries. Although SPICE contain basic components and vendors supply models, parasitic circuit elements must be determined and provided by the SPICE user or other programs. SPICE requires a ground and connected nodes to operate. SPICE assumes, unless otherwise told, ideal components. Many component models do not include such secondary characteristics as thermal rise and breakdown voltage. SPICE sources may provide waveforms. SPICE is capable of performing several types of analysis, and provides an intuitive bridge between time‐ and frequency‐domain. SPICE also includes the ability to set initial conditions to speed the simulation of circuit, including energy‐storing components. SPICE also includes the ability to implement LaPlacian functions. SPICE
has a few faults, but most errors develop from defective models. An understanding of SPICE parameters and of real devices is helpful for correcting erroneous SPICE models.
Superconducting Electromagnets
Authors: Williams John E.C. 
Published: April 2005

AbstractThe design and construction of superconducting magnets has been made possible by the development of technical superconductors. There are three principal materials: the alloy niobiumtitanium (NbTi), the intermetallic compound niobiumtin (Nb3Sn), and the collective high‐temperature superconductors (HTSs) based on copper oxide layers in a perovskite structure.Technical superconductors are a class having special properties that allow superconductor operation in high magnetic fields and with useful current densities. Superconductors are of two types; both can support the flow of electrical current without resistance only below a combination of maximum temperature, field, and current density, with critical parametersTc,Bc, andJc[1]. For type I superconductors, typical values ofTcandBcare 9 K and 0.1 T, respectively. Flux is excluded from the bulk of a type I superconductor, and current flows only in a surface layer, about 10−4 mm thick.By contrast, type II superconductors allow flux to penetrate into the bulk of the lattice in the form of an array of flux quanta.
Surface Acoustic Wave Applications
Authors: Malocha Donald C. 
Published: April 2005

AbstractSince the introduction of the surface acoustic wave (SAW) interdigital transducer in the late 1960s, SAW devices have tremendously affected a broad range of systems. The key to this technology is the ability to sense or tap a traveling electroacoustic wave on a piezoelectric substrate whose velocity is 105 times slower than an electromagnetic wave. The highest cost precision devices are typically used for military and satellite systems, which have the most demanding specifications; the intermediate cost devices are used in modest volume military man packs, military base stations, and commercial base stations; and the lowest cost devices are used in a broad range of commercial and consumer applications. In addition to device technological innovation, research and development on other propagating Rayleigh‐like modes, called pseudo‐SAW, and new substrate materials, such as lithium tetraborate and langasite, have provided lower loss, higher frequency, and wider bandwidth devices.
Surface Acoustic Wave Delay Lines
Authors: Reindl Leonhard M. , Ruppel Clemens C.W. 
Published: April 2005

AbstractSurface acoustic wave (SAW ) delay lines are special microwave components that have been used for electronic analog signal processing since the early 1970s. A tremendous variety of devices and systems for consumer, commercial, and military applications have been developed, running now at an annual rate of some hundred million U.S. dollars. SAW filters, especially linear and nonlinear delay lines, as well as reflective delay lines play a key role in the radiofrequency (RF ) and intermediate‐frequency (IF ) stages of many electronic systems such as radar systems, spread‐spectrum telecommunication systems, and wireless passive sensor systems. The objective of this article is to provide an overview of the latest developments in SAW delay lines and to identify novel emerging applications, especially in the field of wireless communications and sensing. The pertinent key issues for the successful design and mass fabrication of SAW devices are addressed and the underlying operating principles are discussed.
Surface Acoustic Wave Filters
Authors: Hashimoto Ken-ya , Yamaguchi Masatsune 
Published: April 2005

AbstractCurrently, surface acoustic wave (SAW) filters are widely used in RF stages as well as IF stages of modern telecommunication systems. With successful research and development of SAW devices since the early 1960s, the growth of mobile phone markets has accelerated, with surprising advances in SAW device technologies since the early 1990s. This article discusses how the filtering function of SAW devices is realized using various SAW propagation phenomena, and reviews the performance of current commercial SAW filters. First, SAW transversal filters are discussed. Starting from a brief discussion of their fundamentals, we describe achievable performance, impact of the substrate selection and the most recent advances of this type of filter. Next, filters based on SAW resonators are discussed. After giving basic ideas of SAW resonators, it is shown how SAW resonator filters are composed and designed using SAW resonators.
Synthetic Aperture Radar
Authors: Ozdemir Caner 
Published: April 2005

AbstractSince its invention in the early 1950s, synthetic aperture radar (SAR) has gathered increasing attention thanks to its attractive capabilities, such as providing good resolutions both in range and cross‐range dimensions. Although primary exercises of airborne and spaceborne SAR systems were for surveillance purposes and for geophysical remote sensing, numerous applications of SAR have been implemented in many areas, from subsurface imaging to crop monitoring. This article begins with the history of SAR and presents the basic principles in SAR signal processing, including range and azimuth compression. Applications and some common problems in SAR imagery are covered as well. Principles of inverse synthetic aperture radar (ISAR) and its applications are demonstrated with examples. Advanced SAR concepts such as motion compensation, interferometric SAR (IFSAR), and polarimetric SAR (POLSAR) imaging are also presented. The article is concluded by discussing some hot topics and emerging technologies in SAR imagery.
Television Broadcast Transmission Standards
Authors: Godber Alan S. , Redford James R. 
Published: April 2005

AbstractSince the invention of television, images and sound have been captured, processed, transmitted, received, and displayed using analog technology, where the picture and sound elements are represented by signals that are proportional to the image amplitude and sound volume. In more recent years, as solid‐state technology has developed, spurred primarily by the development of computers, digital technology has gradually been introduced into the handling of the television signal, both for image and sound. Many portions of television systems are now hybrid combinations of analog and digital, and it is expected that eventually all television equipment will be fully digital, except for the transducers, cameras, and microphones (whose inputs are analog) and the television displays and loudspeakers (whose outputs are analog).
Transmission Line Matrix (TLM) Method
Authors: Christopoulos Christos 
Published: April 2005

AbstractThis article presents the fundamental ideas behind the transmission‐line modeling or matrix (TLM) method and its applications to complex electromagnetic problems. TLM is considered from different points of view to illustrate its properties and modeling capabilities. A number of more recent enhancements to TLM are presented, especially in the area of materials and multiscale modeling. The article gives a concise introduction to advanced TLM topics and applications.
Transmitters for FM Broadcasting
Authors: Mendenhall Geoffrey N. , Fry P. E. Richard J. 
Published: April 2005

AbstractThe purpose of the FM transmitter is to convert one or more audiofrequency (composite baseband) input signal into a frequency‐modulated, radiofrequency (RF) signal at the desired power output level to feed into the radiating antenna system. In its simplest form, the FM broadcast transmitter can be considered an FM modulator and an RF power amplifier packaged in one unit.
Transmitters for Analog Television
Authors: Collins Gerald W. 
Published: April 2005

Abstract
This article discusses the relevant technology and provides the information needed to understand the operation, design criteria, and some of the future developments of TV transmitters. Although this information is presented from the viewpoint of equipment used in the United States, the principles apply to analog TV broadcasting worldwide. Specific details and numerical constants may differ in other systems, but the fundamental principles are the same.
Transverse Resonance Techniques
Authors: Sorrentino Roberto , Mongiardo Mauro 
Published: April 2005

Abstract
The transverse resonance technique in its various forms is presented and discussed, from the analytical solutions for inhomogeneously filled rectangular waveguides to the conventional approximate solution for transversely discontinuous waveguides (e.g., the ridge waveguide), to the generalized rigorous formulation for waveguide discontinuities and junctions.
Traveling‐Wave Tubes
Authors: Kory Carol L. 
Published: April 2005

AbstractThe traveling‐wave tube (TWT) is a vacuum device invented in the early 1940s [1,2] used for amplification at microwave frequencies. Amplification is attained by surrendering kinetic energy from an electron beam to a radiofrequency (RF) electromagnetic wave. The demand for vacuum devices has been decreasing largely owing to the advent of solid‐state devices. However, although solid state devices have replaced vacuum devices in many areas, there are still many applications such as radar, electronic countermeasures, and satellite communications that require operating characteristics such as high power (watts to megawatts), high frequency (below 1GHz to over 100 GHz), high efficiency (65% efficient, 100 Watt, Kaband TWTs are commonplace), and large bandwidth that only vacuum devices can provide.The term traveling‐wave tube includes both fast‐wave and slow‐wave devices. This article will concentrate on slow‐wave devices as the vast majority of TWTs in operation around the world fall into thiscategory.
Waveguide Antennas
Authors: Kummer Winifred E. 
Published: April 2005

AbstractWaveguide antennas are useful for a variety of airborne, ground‐based, space, and missile applications in the microwave frequency band because they offer high radiating efficiency, a high degree of control over the radiation pattern, compact architecture, and low weight.In waveguide slot arrays the radiating and transmission structures are inexorably intertwined, thus it is appropriate to treat the history of the waveguides together with that of slot radiators.
Waveguide Junctions
Authors: Levy Ralph 
Published: April 2005

AbstractThe properties ofn‐port waveguide junctions are described in fundamental terms, with methods for finding impedance and admittance representations from the scattering matrix, leading to equivalent‐circuit representations. Some of the general properties ofnports are treated, with most examples dealing with three‐ and four‐port junctions. Three‐port networks includeE‐ andH‐plane T junctions andE‐plane bifurcations, and the discussion of four ports includes magic‐Ts and ring hybrids. Emphasis is placed on fundamental properties, the understanding of which is important for future research.
Wavelet Transforms
Authors: Deans Stanley R. , Heine John J. , Gangadharan Deepak , Qian Wei , Kallergi Maria , Clarke Laurence P. 
Published: April 2005

AbstractFunctions that oscillate over time are often called waves. If the function is such that it oscillates only in a localized region and goes to zero outside the region it may be called a wavelet. Thus we say wavelets are localized waves.The fundamental role of the wavelet transform is to facilitate the analysis of signals or images according to scale. Wavelets are functions with some special mathematical properties that serve as a tool for efficiently dividing data into a sequence of frequency components without losing all information about position.
Wavelets
Authors: Tran Boj N. , Nguyen Tien M. , Shihabi Mazen M. 
Published: April 2005

AbstractWavelets have been found to be useful in many scientific and engineering applications, including signal processing, communication, video and image compression, medical imaging, and scientific visualization. The concept of wavelets can be viewed as a synthesis of ideas that originated during the last several decades in engineering, physics, and pure mathematics. The goal of this article is to develop a basic understanding of wavelets, their origin, and their relation to scaling functions, using the theory of multiresolution analysis.
Leaky Modes and High‐Frequency Effects in Microwave Integrated Circuits
Authors: Mesa Francisco , Jackson David R. 
Published: April 2005

AbstractThis article investigates the high‐frequency effects that occur when sources or discontinuities are present on printed‐circuit transmission lines. Although many of the conclusions are general, the analysis and the results will focus on microstrip and stripline types of transmission lines, where there is a single‐strip conductor that is within a layered structure that may contain either one or two ground planes.
Microwave Superconductor Devices
Authors: Sans Carles , Tzuzuki Genichi 
Published: April 2005

AbstractSeveral superconductor device applications in the microwave area are very briefly discussed in the introduction. After that, the article focuses mostly on superconducting filters since it seems that the application that can grow first into commercial success is also the application that generates more interest. First, the basic categories of response used for superconductor filters are discussed. One of them, the quasielliptic response, is preferred for real applications because it provides better cutoff performance. However, filter synthesis and realization of this response is not as straightforward as the Chebyshev response. The synthesis of quasielliptic responses can be done by the cross‐coupling technique, one of the cutting‐edge topics in the microwave filter field.Superconducting technology has opened new horizons in the microwave filter field because superconductors can realize filtering responses that are not realizable with other technologies. Superconductor technology allows very compact planar‐type filter circuits with lumped‐element or distributed structures with very high rejection performance. Many different designs and topologies of superconductor filters have been reported in technical journals and international conferences since the 1990s and to the present, but only several of those can be introduced here in the limited number of pages.Finally, the application of superconductor filters in cellular networks in a form of cryogenic front‐end receivers is discussed. Various different technologies and their integration procedures are considered, such as low‐noise amplifiers, cryogenics, vacuum mechanics, and electronics. Reliability is one of the most important issues in the real world for these applications. Field test results of superconductor filter front‐end systems for TDMA and CDM a applications are also discussed.
Orthomode Transducers
Authors: Gentili G. G. , Nesti R. , Pelosi G. , Selleri S. 
Published: April 2005

Abstract
In the present work orthomode transducers (OMTs) and polarizers are presented. First, field configurations and propagation properties in common waveguides, which are extensively used in OMTs and polarizers, are analyzed to provide the reader with the necessary background to understand both OMTs and polarizers.
As a second step, some OMT and polarizer devices are described in attempt to highlight their electromagnetic features; this is not intended as a full review of all the known OMT and polarizer configurations, which is beyond the scope of this work, but to provide the reader with a basic knowledge of the principles of their operation. This is done by choosing a small, but representative, set of configurations largely used in practice that analyzed in depth and whose understanding, in the author's opinion, gives the reader a broad knowledge of the argument.
Finally, two example designs are presented, the first related to an OMT and the second to a polarizer.
Retrodirective Systems
Authors: Shiroma Wayne A. , Miyamoto Ryan Y. , Shiroma Grant S. , Ohta Aaron T. , Tamamoto Michael A. , Murakami Blaine T. 
Published: April 2005

AbstractA retrodirective system reacts to an incoming signal from an unspecified direction by transmitting a response to that same direction, regardless of what that direction is. This automatic beamsteering feature, performed without any prior knowledge of the location of the source, makes retrodirective systems attractive for automatic pointing and tracking systems, microwave‐tracking beacons, radiofrequency identification, solar power satellites, and small‐satellite crosslinks. This article focuses on retrodirective antenna arrays and their applications and characterization. After reviewing the two basic retrodirective array architectures (Van Atta and phase‐conjugating arrays), several two‐dimensional and millimeter‐wave arrays are then discussed, as well as several key applications in wireless communications.
Underground Propagation
Authors: Zhang Y. P. 
Published: April 2005

Abstract
This article presents both natural and guided propagation of radiowaves in underground structures. By natural propagation, we mean that no special‐purpose cables are strung in underground structures to guide radiowaves, whereas by guided propagation we mean that special‐purpose cables such as leaky feeders are strung in underground structures to guide radiowaves. The imperfect waveguide model is developed for the analysis of natural propagation. It predicts that natural propagation is that of waveguide modes. The fundamental mode is important for long‐distance propagation as it suffers the least attenuation, whereas higher order modes are problematic as they cause fluctuation because of addition or subtraction of these modes. The geometrical optical model is also developed for the analysis of natural propagation. It predicts that natural propagation is achieved via a direct ray and many reflected rays. Only the direct ray and those rays with fewer reflections are significant for long‐distance propagation. The diffuse model is developed for the analysis of guided propagation by coupled‐type leaky feeders. It undertakes to calculate the mean power flow per unit solid angle from a coupled‐type leaky feeder according to Lambert's cosine law. The geometrical optical model is developed for the analysis of guided propagation by radiated‐type leaky feeders. It compares a radiated‐type leaky feeder with an array of magnetic diploes, which radiate energy in a certain direction. Furthermore, the statistical characteristics of both natural and guided propagation are also discussed.
UHF receivers
Authors: Bostlan Charles W. , Sweeney Dennis G. 
Published: April 2005

Abstract
An ultra‐high frequency (UHF) receiver receives radio signals with input frequencies between 300 MHz and 3000 MHz. Radio waves in this part of the spectrum usually follow line‐of‐sight paths and penetrate buildings well. The natural radio environment is significantly quieter at UHF than at lower frequencies, making receiver noise performance more important.