bluuebunny/crossref_metadata_2025_split huggingface dataset:
Superconducting Microwave Technology
Authors: Choudhury Durga P. , Sridhar S. 
Published: November 2024

AbstractSuperconductivity is a remarkable state of matter in which electric current can flow inside materials without any detectable resistance. In a superconductor, perfect electric conductivity or zero resistivity occurs only below a “critical temperature”TC. A direct current induced in a superconducting ring has been shown to persist for over 2 years without any measurable decay. Another important characteristic of superconductors was the discovery by W. Meissner and R. Ochsenfeld in 1933 that a superconductor expels all magnetic flux from its interior; that is, a superconductor is also a perfect diamagnet. A key area of technological applications of superconductors is in high‐frequency devices, particularly at frequencies in the radiowave, microwave, and millimeterwave spectral ranges.
Antennas for Medium‐Frequency Broadcasting
Authors: Rackley Ronald , Folkert Matthew 
Published: November 2024

Abstract
Since the 1940s, there has not been significant development in the area of the antenna element itself as selfsupporting and guyed radiating towers continue to be used much as they were at that time.
New developments have principally involved auxiliary equipment used to test and monitor the antenna system and the means by which the antenna is theoretically analyzed. Digital antenna monitors are used today to accurately monitor the relative current magnitudes and phase relationships of the towers in a directional array while portable solid‐state field strength meters are used to measure radiation patterns. Advances have also been made with improved RF current meters, sampling transformers, and impedance measuring equipment. The design of medium‐frequency broadcast antennas for optimized performance has also seen tremendous advances with the introduction of numerical solutions to electromagnetic problems and nodal modeling of feeder systems made economically possible with personal computers vastly simplifying both design and implementation.
Integrated Circuits
Authors: Ranganathan N. , Venkataramana Raju D. 
Published: November 2024

AbstractThe field of integrated circuits is broad. The inert substrate processes, further divided as thin and thick film processes, yield devices with good resistive and temperature characteristics. However, they are used mostly in low‐volume circuits and in hybrid ICs. The two most popular active substrate materials are silicon and gallium arsenide (GaAs). The silicon processes can be separated into two classes: MOS (the basic device is a metal oxide semiconductor field effect transistor) and bipolar (the basic device is bipolar junction transistors).The transistor–transistor logic (TTL) family of circuits constitutes the most popular type of bipolar and is still used in many high‐volume applications. The emitter‐coupled logic (ECL) devices are used for high‐speed parts that form the critical path delay of the circuit. The MOS family of processes consists of PMOS, NMOS, CMOS, and BiCMOS.
Nonlinear Circuit Design
Authors: Suárez Almudena 
Published: November 2024

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.
Cellular Radio
Authors: Lee William C.Y. 
Published: November 2024

Abstract
The cellular radio system is sometimes called a mobile phone system or a car phone system. Due to the daily needs of subscribers, cellular systems have expanded considerably all over the world. This article discusses the history of cellular systems and the difficulty of deploying them in the mobile radio environment, elaborating on employing digital cellular systems, Personal Communication Services (PCS) mobile satellite systems, and the future IMT‐2000 system.
Mobile Radio Channels
Authors: Vaughan Rodney G. 
Published: November 2024

AbstractIn this article we describe the properties of a communications channel when one or both of the radio terminals is moving. Examples of such channels occur with vehicular terminals and cell phones. However, some properties of these channels also occur in links where some form of multipath occurs, such as point‐to‐point links, where there is also a ground bounce path; long‐range point‐to‐point links with atmospheric refractive paths; and non‐line‐of‐sight links, which rely on radiowave scattering for the propagation paths. The changing phase mix of the multipath causes signal fading and propagation paths. The changing phase mix of the multipath causes signal fading and Doppler shifts in the channel, and these conspire to degrade the quality and capacity of both analog and digital communications. The physical link characteristics and their effects on a digital link are described using tractible mathematical and statistical models.
RF/Wireless Packaging
Authors: Pinel Stephane , Tentzeris Manos , Staicnlescu Daniela , Laskar Joy 
Published: November 2024

AbstractThe electronics packaging industry has proliferated to a point where its technology is at least equally—the semiconductor technology it is designed to serve. The increase in silicon complexity and integration has imposed demanding requirements on packaging technology for higher I/O counts, finer lead pitch, enhanced heat dissipation, and high‐speed, reliable interconnects. At the same time, the industry is also driving toward reduced printed‐circuit‐board area and complexity. From the traditional role of a protective mechanical enclosure, the modern package has been transformed into a sophisticated thermal and electrical management platform.Recent advances in high‐frequency packaging indicate a migration from wirebond (where the chip or die is interconnected to the package only on the periphery of the die) to flip‐chip (where the die is interconnected to the package using the entire die area); and from ceramic to organic packages, with cartridge and multichip technologies emerging as key form factors.The RF front‐end module is the core of the complex systems, and its integration poses a great challenge. Considering the characteristics of the RF modules, such as high performance up to 100 GHz; a large number of high‐performance discrete passive components, design flexibility, reconfigurable architecture, low power consumption, compactness, customized product, short time to market, and low cost, the system‐on package (SoP ) approach has emerged as the most effective means to provide a realistic integration solution as opposed to the system‐on‐chip (SoC ) solution. The strength of SoP is based on multilayer technololgy using low‐cost and high‐performance materials.
Fast Fourier Transforms and Nufft
Authors: Liu Qing Huo 
Published: November 2024

AbstractThe fast Fourier transform (FFT) algorithm is one of most fundamental and powerful computational tools in computational science and engineering. In this article, the development of the fast Fourier transform algorithm is reviewed, some representative applications in electromagnetics are illustrated, and some recent developments in extending the FFT algorithms to nonuniformly sampled data and to discontinuous functions are summarized.
Wavelets
Authors: Tran Boj N. , Nguyen Tien M. , Shihabi Mazen M. 
Published: November 2024

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.
Indium Phosphide (InP)
Authors: Wada Osamu 
Published: November 2024

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.
Traveling‐Wave Tubes
Authors: Kory Carol L. 
Published: November 2024

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.
Electromagnetic Inverse Problems
Authors: Qing Anyong , Gan Yeow Beng 
Published: November 2024

AbstractElectromagnetic inverse problems are discussed in this article. First, these problems are defined; then the mathematical challenges involved and some future research directions in this topic are discussed. A survey on the state of the art in electromagnetic inverse problems is presented next. The survey includes a brief history of the research on electromagnetic inverse problems, an overview of practical application areas, and a brief summary of the fundamental theories involved in the electromagnetic inverse problems and the inversion algorithms developed. The survey also covers the well‐known real dataset and the tested inversion algorithms. Finally, a standard electromagnetic inverse problem—the reconstruction of multiple perfectly conducting cylinders—is presented to demonstrate clearly the aspects of the electromagnetic inverse problems.
Ground Penetrating Radar
Authors: Daniels David J. 
Published: November 2024

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.
Radar Equipment
Authors: Ressler Marc , Bennett Matthew , Ton Tuan , Nguyen Lam 
Published: November 2024

AbstractIn recent years, the improvements in solid‐state devices and the explosive growth in the capabilities of digital circuits and digital processors have provided new approaches to radar designs. Analog circuits, which tend to be smaller and have lower power consumption, are being replaced with digital circuits, which are more stable in the presence of varying temperature, vibration, and power supply voltages, while providing flexibility often unavailable in the analog domain.
UHF receivers
Authors: Bostlan Charles W. , Sweeney Dennis G. 
Published: November 2024

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.
Smart Materials
Authors: Awadelkarim Osama O. , Suliman Samia A. 
Published: November 2024

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.
Magnetic Field Measurement
Authors: Stecher Manfred 
Published: November 2024

AbstractThe measurement of electromagnetic (EM) fields is relevant for various purposes: for scientific and technical applications, for radio propagation, for electromagnetic compatibility (EMC) tests (i.e., testing of the immunity of electronic equipment to electromagnetic emissions aiming at the protection of radio reception from radio interference), and for safety reasons (i.e., the protection of persons from excessive field strengths). For radio propagation and EMC measurements, below about 30MHz a distinction is made between electric and magnetic components of the EM field to be measured. In the area of human safety, this distinction is continued to even higher frequencies.
Feedforward Amplifiers
Authors: Gardner P. 
Published: November 2024

AbstractA feedforward amplifier is a transmitter subsystem in which feedforward linearization is used to correct for the effects of nonlinearities in the gain and phase response of a basic amplifier.Such nonlinearities have the effect of generating intermodulation products in multicarrier systems, and spectral regrowth in systems that use bandlimited, nonconstant envelope modulation. Odd‐order intermodulation is a particular problem in communication systems because it can generate spurious signals very close in frequency to the wanted signals, often in adjacent communication channels. Similarly, spectral regrowth is a problem because it generates unwanted noise or crosstalk in adjacent frequency bands, violating the tough out‐of‐band emissions specifications imposed by modern communication standards. The problems can be reduced, in principle, by the use of separate amplifiers for each channel, and/or linear class A amplifiers backed off well below saturation, but these measures make transmitters highly inefficient.A better compromise between efficiency and linearity can be achieved by using artificial linearization techniques. This article describes one such technique: feedforward linearization. The basic principle of operation is described, the practical limitations are discussed, and comparisons with other linearization techniques are also made. Some advanced techniques are also introduced, including dual‐loop feedforward amplifiers and adaptive feedforward.
Microwave Filters
Authors: Zhu Lei 
Published: November 2024

AbstractThis article summarizes the fundamentals of microwave filters with varied frequency‐selective characteristics such as lowpass, bandpass, highpass, and bandstop. On the basis of the ladder network of a lowpass prototype filter, a well‐known synthesis design approach is described to realize the lowpass frequency response in terms of the preselected insertion loss functions and then determine the element values of this network under the Butterworth and Chebyshev function responses. By executing the frequency transformation from the normalized to actual microwave frequency ranges, various lumped‐element microwave filters are first constructed with both series and shunt elements. Next, the immittance inverters are introduced and utilized to eliminate either series or shunt elements, thus alleviating the complexity in filter implementation. In addition to a series of useful design formulas and tables provided with brief explanations, a variety of practical microwave filters are made up using transmission‐line and waveguide elements and their principles are discussed with regard to their equivalent cascaded networks.
Microwave Oscillators
Authors: Choi Jonghoon , Mortazawi Amir 
Published: November 2024

Abstract
Microwave applications such as communications and radars require stable, efficient, and low‐noise microwave oscillators. For this purpose, microwave oscillators are characterized by their frequency of operation, output power, phase noise, long‐term stability, and DC‐to‐RF efficiency. This article discusses the small‐signal and large‐signal designs of microwave oscillators, based on the negative‐resistance model. Also, the injection‐locking phenomenon is introduced and analyzed employing the equivalent‐circuit model of injection‐locked oscillators. The phase noise of microwave oscillators is explained using Leeson's model. Several practical oscillators are examined. Finally, the state‐of‐the art result for various microwave integrated oscillators is presented.
Monolithic Microwave Integrated Circuits (MMICs)
Authors: Bahl Inder J. 
Published: November 2024

AbstractAdvanced military and microwave systems are demanding increased integration, reliability, radiation hardness, compact size, and lower cost when produced in large volume, whereas the microwave commercial market, including wireless communications, mandates low‐cost circuits. Monolithic microwave integrated circuit (MMIC) technology provides an economically viable approach to meeting these needs. This article deals with MMIC fabrication, substrates, matching networks, active devices, and monolithic design of microwave components and circuits, including device modeling and EM simulations. Typical monolithic microwave circuits and their performance, and MMIC packaging are also discussed.
Slotlines
Authors: Lee Chung-Yi , Itoh Tatsuo 
Published: November 2024

AbstractThis article introduces one type of high‐frequency transmission line called the slotline. The configuration, terminology, analysis, and applications are discussed in subsequent sections. A slotline is an uniplanar wave‐guiding structure proposed by Cohn in 1968. We will use the spectral domain approach to analyze the slotline. The propagation constant and the characteristic impedance are obtained from this rigorous analysis. Slotlines can be built using the same fabrication process for the microstrip line and the coplanar waveguide (CPW). Slotline discontinuities, coaxialto‐slotline, microstrip‐to‐slotline, and CPW‐to‐slotline transitions are investigated in this article.
Smith Chart
Authors: Schwab Leonard M. 
Published: November 2024

Abstract
The Smith chart was routinely used to solve difficult transmission‐line matching problems in a variety of broadcasting, microwave, circuit design, and telecommunication applications. While it has since evolved almost exclusively into a software format, the original paper forms remain a convenient detailed medium for print output of finished work from software implementations of Smith's graphical method.
The essential objective in using the Smith chart is stated simply. An impedance (or equivalent admittance) locus over a frequency range is systematically repositioned on the chart in well‐defined ways by the progressive effects of series or shunt elements, thereby placing the passband portion of the impedance vector in the central area of the chart and the stopband portion at the outer periphery of the chart. The circuit elements commonly used include distributed elements such as transmission lines and quarter‐wave stubs, discrete elements such as inductors and capacitors, and any combination of these and related elements. Resistance elements are seldom intentionally used.
Surface Acoustic Wave Delay Lines
Authors: Reindl Leonhard M. , Ruppel Clemens C.W. 
Published: November 2024

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.