bluuebunny/crossref_metadata_2025_split huggingface dataset:
Noise, Low‐Frequency
Authors: Handel Peter H. 
Published: April 2005

AbstractLow‐frequency noise, containing fluctuations of current or voltage with frequency components below 10 kHz, is mainly fundamental 1/fnoise and sometimes nonfundamental 1/fnoise. In addition, shot noise, generation–recombination (GR) noise, and thermal noise, which are important at higher frequencies, also extend to the low‐frequency domain. All theses forms of electronic noise, are characterized by the mean squared current fluctuation ((δI)2) [or ((δV)2≡RMSδV)2for voltage], measured in series with (or across) the device or sample under test, when a constant voltage (current) is applied, except for thermal noise, which is present even in thermal equilibrium, with no bias applied.
Nonlinear Circuit Design
Authors: Suárez Almudena 
Published: April 2005

AbstractIn this contribution, nonlinear synthesis techniques for microwave circuits are presented. Emphasis is made on their principles, implementation, and applications. Four main types of nonlinear circuit are considered: frequency mixers, oscillators, frequency dividers and frequency multipliers. The operation principles and their main characteristics are introduced, together with the most useful synthesis techniques. Approximate analytic techniques like Volterrra series and the describing funciton are presented, as well as design tools, based on harmonic balance, such as the auxiliary generator, for oscillator and frequency multipliers. Analyses of noise and stability are also carried out. The techniques are illustrated by means of simple but practical FET‐based circuits.
Notch Antennas
Authors: Lee Richard Q. 
Published: April 2005

AbstractNotch antennas, also known as the tapered slot antennas (TSA), have been the topics of research for decades. TSA has demonstrated multioctave bandwidth, moderate gain (7–10 dB), and symmetricE‐ andH‐plane beam patterns and can be used for many different applications. This article summarizes the research activities on notch antennas over the since the early 1990s with emphasis on their most recent advances and applications. The article begins with some discussions on the design of single TSA, then follows with detailed discussions of issues associated with TSA designs and performance characteristics. To conclude the article, some recent developments in TSA arrays and their applications are highlighted.
Phase Noise and Measurements
Authors: Chang Heng-Chia 
Published: April 2005

AbstractThe phase of the electric signals or electromagnetic fields from the circuits and devices is often modulated or demodulated with important information in modern communication systems. However, there are always some random fluctuations in the phase of the signals. The termphase noiseis used to describe such short‐term random fluctuations of the signals. Those phase noise sources may come from the thermal noise (thermal motion of the carriers), shot noise (discrete properties of the electric current sources), or several other mechanisms inside the devices, circuits, or wired or wireless medium [1] The phase noise can affect the signal‐to‐noise ratio (SNR) and bit error rate (BER) of the received signals, and then the channel sensitivity, minimum detectable signal power, operating range, and selectivity in the communication systems. This article focuses on phase noise in the oscillators because most of the phase noise sources in the communication systems come from the oscillators. This article is divided into two main sections on phase noise theory and phase noise measurement techniques.In Section 1 (on phase noise theory), the author describes the simplified oscillator model and its phase dynamics. The oscillator phase noise can be derived by using small‐signal fluctuations around the operating (carrier) frequency, where the fluctuations are caused by the intrinsic noise sources. The Fourier transform and Wiener–Khintchine theorem are applied to the phase noise expressions [2–8]. The relationship between the noise resistance/admittance of the oscillator and Leeson's model is also derived. In Section 2 (on phase noise measurement) several popular measurement techniques [9–13] are explained, including the spectrum analyzer, frequency discrimination, and double‐balanced mixer methods. The author also explains the advantages and disadvantages of these measurement techniques. The article concludes with some references for the interested readers to 10 independently study phase noise theory and related measurement techniques in further detail [1,14–18].
Photonic Bandgap (PBG)
Authors: Martínez Alejandro , Griol Amadeu , Sanchis Pablo , Martí Javier 
Published: April 2005

AbstractPhotonic bandgap materials are expected to play an important role in the near future mainly because of their potential capability to provide extremely compact optical circuits. A large variety of applications have been proposed and demonstrated in both the microwave and optical regimes. In this way, the microwave regime has become a useful instrument to experimentally demonstrate applications initially proposed for the optical domain, thanks to the scaling properties of the Maxwell equations and the easier and cheaper fabrication and testing capabilities of the fabricated structures compared to their optical counterparts. This can be illustrated by the fact that the first photonic bandgap structures were developed to work at microwave frequencies. Photonic bandgap structures have also attracted interest for microwave applications in themselves, and several proposals of electromagnetic bandgap techniques and circuits aimed at improving the properties of current microwave and millimeter‐wave devices have been reported.The concept of photonic bandgap is so wide that it becomes unapproachable to summarize all the knowledge related to this field in a few pages. Thus, although a general vision of the field is offered to the reader, we have focused our efforts on passive microwave components and devices that make use of the principles of photonic bandgap.We start this chapter with a brief historical introduction and a description of photonic bandgap fundamentals. Then, we first summarize some typical functionalities employed in passive optical devices (waveguides, directional couplers, Y junctions, and interferometers), which are tested at microwave frequencies by using a photonic bandgap structure based on alumina rods. The obtained results allow us to visualize a near‐future implementation of the proposed devices using photonic bandgap technology in the optical domain. In a second step, we show how the photonic bandgap concept can be applied to a very extended microwave technology, specifically microstrip technology, and describe and experimentally demonstrate some applications such as novel filter structures and harmonic suppression in microstrip bandpass filters based on coupled rings. Finally, a brief summary of the application of photonic bandgap structures in the optical regime is drawn.
Spatial and Quasi‐Optical Power Combining
Authors: Navarro Julio A. 
Published: April 2005

AbstractSpatial and Quasi‐Optical Power Combining by Dr. Julio A. Navarro reviews the early history of radar and some critical microwave sources and components which have made the concept viable and successful since its conception. The contribution provides background to the field by referencing power combining review papers and spatial power combining textbooks. This work also references significant contributors to active antennas and power combining in the past decade. The article updates major improvements in the field since the mid‐1990s when the first textbook on the subject was written. The contribution lists key qualities and figures‐of‐merit to gauge the success of on‐going research and adequately compare its results with others in the field. These qualities are described along with methods for calculation to assist newcomers working in the field. Additional areas for research are briefly described to highlight some of the more recent off‐shoots of this field.
Q‐Factor
Authors: Kajfez Darko 
Published: April 2005

AbstractRadiofrequency and microwave resonators are characterized by their resonant frequency, coupling coefficient, and unloadedQfactor. Definition of theQfactor consists of a ratio of the stored energy and the dissipated power at resonant frequency. The distinction should be made between the unloaded, loaded, and externalQ. The article provides some frequently used equations related to the application ofQfactors. The measurement techniques for determining theQfactor can be classified as being of transmission type, reflection type, and reaction type. The measurement is typically performed with a vector network analyzer and a curve‐fitting procedure is applied to determine the loaded resonant frequency, the loadedQ, and the coupling coefficient. The measurement is redundant as many more data points are taken then minimum necessary, so that it becomes possible to estimate the random uncertainty of the unloadedQ.
Quadrature Phase Shift Keying (QPSK)
Authors: Tatu Serioja O. , Bosisio Renato G. 
Published: April 2005

AbstractQuadrature phase shift keying (QPSK) is a modulation technique used for sending data over radio or cable networks.This article presents in details the QPSK principle, as well as modulators and demodulators using the conventional approach. A new concept to modulate or to demodulate a QPSK signal using the six‐port circuit at millimeter‐wave frequencies is also presented.The coherent carrier recovery circuit for the demodulation of QPSK signals is an important aspect to be considered. Three regeneration schemes (Costas loop, multiplication loop, and reverse modulation loop) are presented.The probability of error for QPSK in the presence of noise is derived using the equations of I‐ and Q‐demodulated signals.
Radar Antennas
Authors: Cui Tie Jun , Chew Weng Cho , Chen Fu-Chiarng 
Published: April 2005

AbstractThe radar antenna is an important component of radar. For different radar types, the requirement for antenna performances and functions is varied. Because the subject of radar antennas is very extensive, only selected types and performances of radar antennas are discussed in this article. Therefore, because of limited space, we discuss only reflector antennas and array antennas.
Radar Applications
Authors: Tsihrintzis George A. 
Published: April 2005

AbstractRadar (radiodetection andranging) systems attempt to infer information about remotely located objects from reflections of deliberately generated electromagnetic waves at radio‐ and microwave frequencies. Typically, the information sought is detection of the presence of target objects in the midst of clutter, recognition (classification) of targets, and estimation of target parameters such as range distance from the radar antenna), bearing (azimuth and elevation), orientation, velocity, acceleration, or backscattering cross section (reflectivity) distribution. Today's radar systems perform these tasks for multiple targets simultaneously, at the finest possible target resolution and with the highest possible accuracy. Additionally, the domain of utilization of radar techniques has expanded beyond the traditional aircraft detection and ranging application. Indeed, modern radar applications include search, tracking, and navigation radar for spread targets, high‐resolution aerial imaging radar, weather observation radar, and ground‐ and foliage‐penetrating radar. To achieve their expanded tasks, modern radar systems combine high‐quality hardware with sophisticated signal design and processing algorithm development and implementation based on statistical descriptions of both the target characteristics and the clutter distributions.
Radar Imaging
Authors: Chen Victor C. 
Published: April 2005

AbstractRadar imaging is an imaging method obtained by processing radar signals reflected from an object and generating an image of that object. The purpose of this article is to introduce basic concepts of radar imaging, including radar imaging geometry, synthetic aperture, stripmap mode, spotlight mode, and inverse mode. This article summarizes algorithms for radar imaging, including the range–Doppler algorithm, range migration algorithm, chirp‐scale algorithm, polar formatting algorithm, phase gradient algorithm, prominent point processing algorithm, and time–frequency‐based image formation algorithm. Issues in radar imaging of moving targets are also introduced.
Radar Polarimetry
Authors: Sletten Mark A. , Mc Laughlin David J. 
Published: April 2005

AbstractThis article summarizes the fundamentals of radar polarimetry and gives examples of related applications and research. The mathematical foundation is described first. This discussion includes explanations of the various ways in which polarized and partially polarized electromagnetic waves can be described and how formalisms are used to express the polarimetric scattering properties of objects and surfaces. The scattering, Mueller, covariance, and coherency matrices embody these formalisms. Some practical aspects of polarimetric radar design are then discussed, and the article concludes by summarizing applications of polarimetry and areas of active research, including scattering studies, image classification, contrast enhancement, meteorology, and topographic mapping.
Radio‐Frequency Identification Systems (RFID)
Authors: Hayashi Hitoshi 
Published: April 2005

AbstractRadiofrequency identification system (RFIDs) can provide an automatic means of collecting identification data for people, animals, and objects. Furthermore, with the advent of Internet systems, RFID systems are expected to further expand into new ubiquitous applications. In this article, we present a brief introduction to RFID systems.
Radio‐Frequency Integrated Circuits
Authors: Chongcheawchamnan M. , Karacaoglu U. , Robertson I.D. 
Published: April 2005

AbstractSilicon RFIC technology has become dominant for mobile and wireless applications in the low gigahertz range, and with heterojunction devices, the circuits are moving into the millimeter‐wave range. This article provides a summary of the technology, design, and application of RFICs.The article includes sections on devices, passive components, CAD, amplifier design, oscillators, mixers, filters, and transceivers. It presents an overview of each topic, to give an up‐to‐date background in each topic.A substantial part of the article is on modern aspects such as realizing high‐Qinductors, high‐efficiency power amplifiers, frequency synthesis, and direct conversion transceivers architectures. It finishes by describing the importance of considering the package integration as an important part of the design and the system‐in‐package concept.
Microwave and Radio Frequency Multipliers
Authors: Thomas D.G. , Branner G.R. , Kumar B.P. 
Published: April 2005

AbstractMicrowaved RF frequency multipliers are electronic devices that generate signals having frequencies that are integral multipliers of their input signal frequencies. These devices have applications in electronic instruments, radar, electronic warfare, and communication systems. This article covers theory and design of these devices that operate from the megahertz to millimeter‐wave regions. Detailed discussions of both passive and active realizations are included along with state‐of‐the‐art practical design examples. Over 170 references covering the current multiplier technology in RF and microwave bands are included.
Radio on Fiber Systems (RoF Systems)
Authors: Komaki Shozo , Tsukamoto Katsutoshi 
Published: April 2005

AbstractThe radio‐on‐fiber (RoF) system involves the synergetic use of emerging wireless and photonic technologies and has advantages of both wide‐area radio access capability and the low‐loss long‐hop transmission capability of optical fibers simultaneously. Since the RoF system directly converts the RF signal to an optical signal, this system provides universal network solutions that are independent of frequency band and air interface types. In this section, the basic configurations of the RoF system, devices, performance, and present and future applications of networking have been described.
Radiotelemetry
Authors: Tsou Haiping , Cheung Kar-ming 
Published: April 2005

AbstractRadiotelemetry, by definition, is the science and technology of automatically measuring and transmitting data by radio from remote sources, as from space vehicles, to receiving stations for recording and analysis. It involves preparing of data generated at remote sources, transmitting data through radio channels, and processing data at the receiving stations. Behind these three tasks, how to convey the information in a reliable and timely manner through a communication link is the most fundamental problem in this field.
Rough Surface Scattering: Numerical Simulations and Applications in Microwave Remote Sensing
Authors: Li Qin , Xia Ming Yao , Tsang Leung , Zhou Lin , Chan Chi Hou , Li Zhong Xin 
Published: April 2005

AbstractIn this article we present rough‐surface bistatic scattering and emission based on NMM3D (numerical Maxwell model using 3D simulations). Results are computed using the method of sparse matrix canonical grid with RWG (Rao–Wilton–Glisson) basis functions. Results are illustrated for active and passive microwave remote sensing of soil moisture and ocean. We also describe recent numerical simulation techniques of the single integral equation and the multilevel UV method in rough surface scattering.
Schottky Barrier Diodes and Their Applications
Authors: Davis W. Alan 
Published: April 2005

AbstractAlthough times have changed, the Schottky barrier diode remains an important component in many systems because of its unique features.The discussion will first focus on the origin of the energy bands and their relationship to the Fermi level. The simple theory is later modified by the barrier‐lowering effect and the presence of surface states. The reverse bias depletion capacitance and, subsequently, the forward current characteristics are determined. Equivalent circuit models are discussed that are useful for circuit design. Finally, some comments are made about recent progress in wide bandgap Schottky barrier diodes. The applications sections emphasize mixer design, as this seems to be the predominant use of Schottky devices.
SiC Device Technologies
Authors: Östling M. , Koo S.-M. , Domeij M. , Danielsson E. , Zetterling C.-M. 
Published: April 2005

AbstractSilicon carbide (SiC) devices have drawn considerable attention for use in various applications due to the interesting materials properties of SiC. Commercial products are now available for high‐voltage and high‐frequency applications. Prototype devices show promising performance, whereas materials issues are still a hinder for economically viable production of large‐area devices with high yield. This article reviews the more recent progress in SiC devices and process technology and presents the state‐of‐the‐art SiC devices as well as new application areas such as ferroelectric field‐effect transistors (FeFETs).
Slotline Components
Authors: Fan Lu , Chang Kai 
Published: April 2005

AbstractThis article first discusses the fundamental slotline elements such as various T junctions, resonators, and transitions. After these general topics, several kinds of passive slotline integrated circuits are presented through a discussion of filters, hybrid couplers, and nonreciprocal devices. Finally, the applications of slotline to solid‐state integrated circuits, that is, mixers, oscillators, modulators, and frequency doublers, are described. These applications are supported by real circuit demonstrations and actual circuit performances. The implementation of solid‐state devices for the tuning and switching of resonances is also discussed.
Smart Materials
Authors: Awadelkarim Osama O. , Suliman Samia A. 
Published: April 2005

AbstractIn this article, we give the reader a brief introduction to a selected number of smart materials and structures. These materials include semiconductors and related structures, superconductors, piezoelectric materials, and shape memory materials. These materials are discussed in terms of their electrical, mechanical, optical, and chemical properties and possible engineering applications in the fields of nanoelectronics, nano/microelectromechanical systems, optoelectronics, and communication.
Standing Wave Meters and Network Analyzers
Authors: Schiek Burkhard , Gronefeld Andreas 
Published: April 2005

AbstractThis article will present a number of measurement systems for the determination of reflection coefficients (one‐port network analyzer or reflectometer) and for full characterization of two‐port networks. Although the concept ofS‐parameters is easily extended toN‐ports, measurement of networks with more than two ports will not be covered, because most commercially available hardware is built for two‐port measurements and can be used to characterizeN‐ports by simply terminating the unused N‐2 ports inZ0.
III–V Semiconductors
Authors: Snowden Christopher M. 
Published: April 2005

AbstractThis article provides a broad introduction to III–V semiconductors as a background to device and circuit technologies that use these materials. The reader is introduced to theoretical and practical concepts for this range of alloy semiconductors. The physical and chemical properties and behavior of these materials are discussed. Methods of growing epitaxial layers and fabricating microwave and RF devices are presented. A brief summary of the microwave applications of III–V semiconductors is included together with an overview of the state‐of‐the‐art performance.
Target Tracking
Authors: Drummond Oliver E. 
Published: April 2005

AbstractTarget tracking design and development is challenging if the measurement density is not sparse. Close targets, clutter , or false signal can cause conditions of dense measurements. The tracking algorithms used for a system need to be selected based on the specifics of the application. This article addresses alternative algorithms for both single and multiple target tracking; tracking using either a single sensor or data from multiple sensors (sensor data fusion); and discusses trade‐offs considerations for selecting appropriate algorithms for a system.
Volterra Modeling in Analog, RF and Microwave Engineering
Authors: Steer Michael B. , Gharaibeh Khaled M. 
Published: April 2005

AbstractVolterra techniques are used in radiofrequency (RF) and Microwave engineering primarily in modeling the inputoutput characteristics of nonlinear circuits and systems that operate with limited bandwidth signals. Volterra models capture frequency‐dependent effects within the band. Two forms of the Volterra model exist; one being in the time‐domain invoking Volterra kernels in what is in effect a multidimensional convolution; and the other being a frequency‐domain form with what are called Volterra nonlinear transfer function akin to the transfer functions of linear circuits but, of course, extended to handle nonlinearities.
Waveguide Directional Couplers
Authors: Levy Ralph 
Published: April 2005

AbstractWaveguide directional couplers are widely used as power monitors in microwave systems and test equipment. An even more important set of applications makes use of the 90° phase difference between the output signals, making them ideal for antenna feed networks, and as hybrid junctions or couplers for applications in balanced mixers, duplexers, and balanced amplifiers. Their common basic properties are outlined, and the design of the most common and useful types are described, namely, multiaperture and cross‐guide couplers, sidewall and topwall hybrids, and branch‐guide couplers. Modern design techniques based on exact synthesis are emphasized.
Waveguide Oscillators
Authors: Holzman Eric L. 
Published: April 2005

AbstractWaveguide oscillators are DC‐to‐RF converters most commonly used as millimeter‐wave sources. This article describes the fundamentals of solid‐state, two‐terminal device oscillators employing waveguide circuits as resonators. Single‐device oscillators, varactor‐controlled oscillators, and waveguide resonant cavity combiners are overviewed.