Download or read book Applications of Gallium Nitride FETs to RF Arrays for Magnetic Resonance Imaging written by Michael D. Twieg and published by . This book was released on 2015 with total page 210 pages. Available in PDF, EPUB and Kindle. Book excerpt: Magnetic resonance imaging (MRI) is an imaging technique with incredible utility for medical applications, along with incredible technical complexity. Two of the primary subsystems of an MRI scanner are the RF transmit and receive chains, containing coils, switches, and amplifiers. The RF chains’ fundamental architecture has changed little since its inception, with Silicon transistors dominating the roles of switches and amplifiers.Recent trends have pushed the RF chains toward parallelized design in order to increase image quality, reduce scan time, and/or improve patient safety. Parallel RF chains face technical challenges due to the density of electronics and cables required. For receive chains the challenge is modest; clinical scanners with 128 receive channels are already available. For transmit chains, the challenge is severe due to the large amount of power dissipation and transmission required. Currently commercial systems are limited to 8 transmit channels, and at very high cost.Here we advocate for the replacement of older circuits with more efficient versions based on high performance transistors. In particular, we demonstrate eGaN FETs as a replacement for PIN diodes for active detuning circuits in receive coils. Unlike PIN diodes, FETs can be controlled with voltage, and require almost no bias current, which drastically simplifies the design and construction of large receive arrays.We also demonstrate eGaN FETs for RF power amplifier (RFPA) modules aimed towards parallel transmit (pTX) chains with high channel counts. The eGaN RFPA modules demonstrate far higher power efficiency and density than linear RFPAs based on Si LDMOS FETs, and can operate within the scanner bore.Since our RFPAs are built on switchmode topologies, we explore the nonlinear and time-varying behavior of coupled amplifiers using experimental and numerical methods. Our results show that pTX chains based on these modules have higher efficiency and lower coupling than pTX chains built with linear RFPAs terminated with isolators, and that these benefits increase with the number of channels in the array. We anticipate that the low cost and high performance of the modules will drastically reduce the cost of pTX chains, greatly increasing the value of MRI to millions of patients.

Download or read book GaN Transistors for Efficient Power Conversion written by Alex Lidow and published by John Wiley & Sons. This book was released on 2019-08-12 with total page 470 pages. Available in PDF, EPUB and Kindle. Book excerpt: An up-to-date, practical guide on upgrading from silicon to GaN, and how to use GaN transistors in power conversion systems design This updated, third edition of a popular book on GaN transistors for efficient power conversion has been substantially expanded to keep students and practicing power conversion engineers ahead of the learning curve in GaN technology advancements. Acknowledging that GaN transistors are not one-to-one replacements for the current MOSFET technology, this book serves as a practical guide for understanding basic GaN transistor construction, characteristics, and applications. Included are discussions on the fundamental physics of these power semiconductors, layout, and other circuit design considerations, as well as specific application examples demonstrating design techniques when employing GaN devices. GaN Transistors for Efficient Power Conversion, 3rd Edition brings key updates to the chapters of Driving GaN Transistors; Modeling, Simulation, and Measurement of GaN Transistors; DC-DC Power Conversion; Envelope Tracking; and Highly Resonant Wireless Energy Transfer. It also offers new chapters on Thermal Management, Multilevel Converters, and Lidar, and revises many others throughout. Written by leaders in the power semiconductor field and industry pioneers in GaN power transistor technology and applications Updated with 35% new material, including three new chapters on Thermal Management, Multilevel Converters, Wireless Power, and Lidar Features practical guidance on formulating specific circuit designs when constructing power conversion systems using GaN transistors A valuable resource for professional engineers, systems designers, and electrical engineering students who need to fully understand the state-of-the-art GaN Transistors for Efficient Power Conversion, 3rd Edition is an essential learning tool and reference guide that enables power conversion engineers to design energy-efficient, smaller, and more cost-effective products using GaN transistors.

Download or read book Magnetic Resonance and Its Applications written by Vladimir I. Chizhik and published by Springer Science & Business Media. This book was released on 2014-04-08 with total page 785 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book is devoted to the description of the fundamentals in the area of magnetic resonance. The book covers two domains: radiospectroscopy and quantum radioelectronics. Radiospectroscopy comprises nuclear magnetic resonance , electron paramagnetic resonance, nuclear quadrupolar resonance, and some other phenomena. The radiospectroscopic methods are widely used for obtaining the information on internal (nano, micro and macro) structure of objects. Quantum radioelectronics, which was developed on the basis of radiospectroscopic methods, deals with processes in quantum amplifiers, generators and magnetometers. We do not know analogues of the book presented. The book implies a few levels of the general consideration of phenomena, that can be useful for different groups of readers (students, PhD students, scientists from other scientific branches: physics, chemistry, physical chemistry, biochemistry, biology and medicine).

Download or read book Chemical Abstracts written by and published by . This book was released on 2002 with total page 2540 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book AlGaN GaN HEMT power amplifiers with optimized power added efficiency for X band applications written by Jutta Kühn and published by KIT Scientific Publishing. This book was released on 2011 with total page 264 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work has arisen out of the strong demand for a superior power-added efficiency (PAE) of AlGaN/GaN high electron mobility transistor (HEMT) high-power amplifiers (HPAs) that are part of any advanced wireless multifunctional RF-system with limited prime energy. Different concepts and approaches on device and design level for PAE improvements are analyzed, e.g. structural and layout changes of the GaN transistor and advanced circuit design techniques for PAE improvements of GaN HEMT HPAs.

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1976 with total page 984 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Distributed Power Amplifiers for RF and Microwave Communications written by Narendra Kumar and published by Artech House. This book was released on 2015-06-01 with total page 365 pages. Available in PDF, EPUB and Kindle. Book excerpt: This new resource presents readers with all relevant information and comprehensive design methodology of wideband amplifiers. This book specifically focuses on distributed amplifiers and their main components, and presents numerous RF and microwave applications including well-known historical and recent architectures, theoretical approaches, circuit simulation, and practical implementation techniques. A great resource for practicing designers and engineers, this book contains numerous well-known and novel practical circuits, architectures, and theoretical approaches with detailed description of their operational principles.

Download or read book Physical Properties of III V Semiconductor Compounds written by Sadao Adachi and published by John Wiley & Sons. This book was released on 1992-11-10 with total page 342 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this book is two-fold: to examine key properties of III-V compounds and to present diverse material parameters and constants of these semiconductors for a variety of basic research and device applications. Emphasis is placed on material properties not only of Inp but also of InAs, GaAs and GaP binaries.

Download or read book GaN Power Devices and Applications written by Alex Lidow and published by . This book was released on 2021-10 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: GaN Power Devices and Applications, provides an update on gallium nitride (GaN) technology and applications by leading experts. It includes detailed descriptions of the latest examples of GaN's usage in power supplies, lidar systems, motor drives, and space applications.

Download or read book Microwave Circuit Design Using Linear and Nonlinear Techniques written by George D. Vendelin and published by John Wiley & Sons. This book was released on 2005-10-03 with total page 1080 pages. Available in PDF, EPUB and Kindle. Book excerpt: The ultimate handbook on microwave circuit design with CAD. Full of tips and insights from seasoned industry veterans, Microwave Circuit Design offers practical, proven advice on improving the design quality of microwave passive and active circuits-while cutting costs and time. Covering all levels of microwave circuit design from the elementary to the very advanced, the book systematically presents computer-aided methods for linear and nonlinear designs used in the design and manufacture of microwave amplifiers, oscillators, and mixers. Using the newest CAD tools, the book shows how to design transistor and diode circuits, and also details CAD's usefulness in microwave integrated circuit (MIC) and monolithic microwave integrated circuit (MMIC) technology. Applications of nonlinear SPICE programs, now available for microwave CAD, are described. State-of-the-art coverage includes microwave transistors (HEMTs, MODFETs, MESFETs, HBTs, and more), high-power amplifier design, oscillator design including feedback topologies, phase noise and examples, and more. The techniques presented are illustrated with several MMIC designs, including a wideband amplifier, a low-noise amplifier, and an MMIC mixer. This unique, one-stop handbook also features a major case study of an actual anticollision radar transceiver, which is compared in detail against CAD predictions; examples of actual circuit designs with photographs of completed circuits; and tables of design formulae.

Download or read book Coplanar Waveguide Circuits Components and Systems written by Rainee N. Simons and published by John Wiley & Sons. This book was released on 2004-04-07 with total page 461 pages. Available in PDF, EPUB and Kindle. Book excerpt: Up-to-date coverage of the analysis and applications of coplanar waveguides to microwave circuits and antennas The unique feature of coplanar waveguides, as opposed to more conventional waveguides, is their uniplanar construction, in which all of the conductors are aligned on the same side of the substrate. This feature simplifies manufacturing and allows faster and less expensive characterization using on-wafer techniques. Coplanar Waveguide Circuits, Components, and Systems is an engineer's complete resource, collecting all of the available data on the subject. Rainee Simons thoroughly discusses propagation parameters for conventional coplanar waveguides and includes valuable details such as the derivation of the fundamental equations, physical explanations, and numerical examples. Coverage also includes: Discontinuities and circuit elements Transitions to other transmission media Directional couplers, hybrids, and magic T Microelectromechanical systems based switches and phase shifters Tunable devices using ferroelectric materials Photonic bandgap structures Printed circuit antennas

Download or read book Reflectionless Filters written by Matthew A. Morgan and published by Artech House. This book was released on 2017-01-31 with total page 277 pages. Available in PDF, EPUB and Kindle. Book excerpt: This invaluable resource introduces progressive techniques for the creation of sophisticated reflectionless filter topologies that have identically zero reflection coefficient at all frequencies. Practical implementations are discussed along with their advantages when compared to classical absorptive filters and their benefits in real-world systems such as up/down converters, multiplier chains, broadband amplifiers, analog-to-digital converters, and time-domain applications. This book offers insight into the innovative process of developing reflectionless filters from first principles using both lumped elements and transmission lines. Tools for the creation of reflectionless multiplexers, matched sloped equalizers, and advanced, high-order, and nonplanar topologies are also presented.

Download or read book GaAs and Related Materials written by Sadao Adachi and published by World Scientific. This book was released on 1994 with total page 700 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book covers the various material properties of bulk GaAs and related materials, and aspects of the physics of artificial semiconductor microstructures, such as quantum wells and superlattices, made of these materials. A complete set of the material properties are considered in this book. They are structural properties; thermal properties; elastic and lattice vibronic properties; collective effects and some response characteristics; electronic energy-band structure and consequences; optical, elasto-optic, and electro-optic properties; and carrier transport properties. This book attempts to summarize, in graphical and tabular forms, most of the important theoretical and experimental results on these material properties. It contains a large number of references useful for further study. Timely topics are discussed as well. This book will be of interest to graduate students, scientists and engineers working on semiconductors.

Download or read book Technology of Gallium Nitride Crystal Growth written by Dirk Ehrentraut and published by Springer Science & Business Media. This book was released on 2010-06-14 with total page 337 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book discusses the important technological aspects of the growth of GaN single crystals by HVPE, MOCVD, ammonothermal and flux methods for the purpose of free-standing GaN wafer production.

Download or read book The Physics of Semiconductor Devices written by R. K. Sharma and published by Springer. This book was released on 2019-01-31 with total page 1299 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book disseminates the current knowledge of semiconductor physics and its applications across the scientific community. It is based on a biennial workshop that provides the participating research groups with a stimulating platform for interaction and collaboration with colleagues from the same scientific community. The book discusses the latest developments in the field of III-nitrides; materials & devices, compound semiconductors, VLSI technology, optoelectronics, sensors, photovoltaics, crystal growth, epitaxy and characterization, graphene and other 2D materials and organic semiconductors.

Download or read book Analysis and Application of Analog Electronic Circuits to Biomedical Instrumentation written by Robert B. Northrop and published by CRC Press. This book was released on 2003-12-29 with total page 566 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book introduces the basic mathematical tools used to describe noise and its propagation through linear systems and provides a basic description of the improvement of signal-to-noise ratio by signal averaging and linear filtering. The text also demonstrates how op amps are the keystone of modern analog signal conditioning systems design, and il

Download or read book Piezoelectric MEMS Resonators written by Harmeet Bhugra and published by Springer. This book was released on 2017-01-09 with total page 423 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book introduces piezoelectric microelectromechanical (pMEMS) resonators to a broad audience by reviewing design techniques including use of finite element modeling, testing and qualification of resonators, and fabrication and large scale manufacturing techniques to help inspire future research and entrepreneurial activities in pMEMS. The authors discuss the most exciting developments in the area of materials and devices for the making of piezoelectric MEMS resonators, and offer direct examples of the technical challenges that need to be overcome in order to commercialize these types of devices. Some of the topics covered include: Widely-used piezoelectric materials, as well as materials in which there is emerging interest Principle of operation and design approaches for the making of flexural, contour-mode, thickness-mode, and shear-mode piezoelectric resonators, and examples of practical implementation of these devices Large scale manufacturing approaches, with a focus on the practical aspects associated with testing and qualification Examples of commercialization paths for piezoelectric MEMS resonators in the timing and the filter markets ...and more! The authors present industry and academic perspectives, making this book ideal for engineers, graduate students, and researchers.