Author: Aimad Saib Publisher: Presses univ. de Louvain ISBN: 9782930344775 Category : Science Languages : en Pages : 196
Book Description
As wireless communication systems are flourishing and operating frequencies are progressively increasing, there exists nowadays a strong demand for RF devices at millimeter wavelengths. Nonmetallic ferromagnetic materials, also called ferrites, have found wide applications in RF technology as they possess the combined properties of a magnetic material and an electrical insulator. The remarkable flexibility in tailoring the magnetic properties, the very high resistivity, price and performance considerations make ferrites the first choice materials for microwave applications. However, the frequency range of operation, the bandwidth, and the aptitude to be integrated in MMICs should be improved. In this work, a new class of magnetic materials which could overcome the main disadvantages encountered when using ferrites in RF devices operating at millimeter wavelengths is studied. This material, called magnetic nanowired substrate (MNWS), is composed of an array of ferromagnetic nanowires embedded in a polymer substrate. First, the ferromagnetic nature of nanowires yields very high saturation magnetizations, thus operating frequencies higher than 40 GHz. Next, the nanometric wire diameter allows an easy penetration of electromagnetic waves inside the MNWS. Moreover, due to the high aspect ratio of nanowires the desired magnetic properties are obtained without an external magnetic field. This leads to a considerable potential increase of the compactness and ease of integration in MMICs. Various potential applications, such as filters and circulators, of this new material are presented.
Author: Judith Spiegel Publisher: Presses univ. de Louvain ISBN: 2874631965 Category : Science Languages : en Pages : 179
Book Description
The growing interest in integrated microwave devices for automotive and wireless communication demands reducing device dimension by increasing bandwidth and operating frequency is a major challenge. This thesis presents the design of such devices.
Author: Qi-jun Zhang Publisher: World Scientific ISBN: 1848169221 Category : Technology & Engineering Languages : en Pages : 526
Book Description
Computer-aided full-wave electromagnetic (EM) analysis has been used in microwave engineering for the past decade. Initially, its main application area was design verification. Today, EM-simulation-driven optimization and design closure become increasingly important due to the complexity of microwave structures and increasing demands for accuracy. In many situations, theoretical models of microwave structures can only be used to yield the initial designs that need to be further fine-tuned to meet given performance requirements. In addition, EM-based design is a must for a growing number of microwave devices such as ultra-wideband (UWB) antennas, dielectric resonator antennas and substrate-integrated circuits. For circuits like these, no design-ready theoretical models are available, so design improvement can only be obtained through geometry adjustments based on repetitive, time-consuming simulations. On the other hand, various interactions between microwave devices and their environment, such as feeding structures and housing, must be taken into account, and this is only possible through full-wave EM analysis.Electromagnetic simulations can be highly accurate, but they tend to be computationally expensive. Therefore, practical design optimization methods have to be computationally efficient, so that the number of CPU-intensive high-fidelity EM simulations is reduced as much as possible during the design process. For the same reasons, techniques for creating fast yet accurate models of microwave structures become crucially important.In this edited book, the authors strive to review the state-of-the-art simulation-driven microwave design optimization and modeling. A group of international experts specialized in various aspects of microwave computer-aided design summarize and review a wide range of the latest developments and real-world applications. Topics include conventional and surrogate-based design optimization techniques, methods exploiting adjoint sensitivity, simulation-based tuning, space mapping, and several modeling methodologies, such as artificial neural networks and kriging. Applications and case studies include microwave filters, antennas, substrate integrated structures and various active components and circuits. The book also contains a few introductory chapters highlighting the fundamentals of optimization and modeling, gradient-based and derivative-free algorithms, metaheuristics, and surrogate-based optimization techniques, as well as finite difference and finite element methods./a
Author: Manuel Vázquez Publisher: Woodhead Publishing ISBN: 0081028326 Category : Technology & Engineering Languages : en Pages : 1010
Book Description
Magnetic Nano-and Microwires: Design, Synthesis, Properties and Applications, Second Edition, reviews the growth and processing of nanowires and nanowire heterostructures using such methods as sol-gel and electrodeposition, focused-electron/ion-beam-induced deposition, epitaxial growth by chemical vapor transport, and more. Other sections cover engineering nanoporous anodic alumina, discuss magnetic and transport properties, domains, domain walls in nano-and microwires. and provide updates on skyrmions, domain walls, magnetism and transport, and the latest techniques to characterize and analyze these effects. Final sections cover applications, both current and emerging, and new chapters on memory, sensor, thermoelectric and nanorobotics applications. This book will be an ideal resource for academics and industry professionals working in the disciplines of materials science, physics, chemistry, electrical and electronic engineering and nanoscience. Details the multiple key techniques for the growth, processing and characterization of nanowires and microwires Reviews the principles and difficulties involved in applying magnetic nano- and microwires to a wide range of applications, also including biomedical and sensing applications Discusses magnetism and transport in nanowires, skyrmions and domain walls in nanowires and the latest innovations in magnetic imaging
Author: Filippo Capolino Publisher: CRC Press ISBN: 1351835270 Category : Technology & Engineering Languages : en Pages : 1199
Book Description
This book uses the first volume’s exploration of theory, basic properties, and modeling topics to develop readers’ understanding of applications and devices that are based on artificial materials. It explores a wide range of applications in fields including electronics, telecommunications, sensing, medical instrumentation, and data storage. The text also includes a practical user’s guide and explores key areas in which artificial materials have developed. It includes experts’ perspectives on current and future applications of metamaterials, to present a well-rounded view on state-of-the-art technologies.
Author: Xiaoming Kou Publisher: ISBN: 9781124612188 Category : Ferromagnetic resonance Languages : en Pages :
Book Description
Ferromagnetic nanowire arrays embedded in insulating matrices have attracted great attention in recent years for their rich physics and potential as sensor and microwave applications. Magnetic nanowires made of 3d transitional metals or their alloys have the advantages of high saturation magnetizations, limited eddy current loss, and guaranteed microwave penetration due to nanometer size. The nanowire arrays can also have high ferromagnetic resonance (FMR) frequencies due to shape anisotropy. In this work, the following new phenomena of magnetic nanowire arrays are demonstrated and explained with a theoretical model. (1) A simple theoretical analysis indicates that high permeability is possible in nanowire arrays with the magnetocrystalline anisotropy comparable to the demagnetization energy and its easy axis perpendicular to the nanowire. With proper conditions, we have fabricated Co nanowire arrays with a crystalline easy axis perpendicular to the nanowire. For Co nanowire arrays with certain geometries, high permeability and low losses have been achieved. (2) Magnetic materials with tunable FMR are highly desirable in microwave devices. We demonstrate that the natural FMR of Ni 90 Fe 10 nanowire array can be tuned continuously from 8.2 to 11.7 GHz by choosing different remanent state. Theoretical model based on dipolar interaction among nanowires has been developed to explain the observed phenomena. A double FMR feature caused by dipolar interaction in magnetic nanowire array was predicted and verified in Co nanowires. (3) A memory effect has also been demonstrated in magnetic nanowire arrays. The magnetic nanowire array has the ability to record the maximum magnetic field that the array has been exposed to after the field has been turned off. The origin of the memory effect is the strong magnetic dipole interaction among the nanowires. Based on the memory effect, a novel and extremely low cost EMP detection scheme is proposed. It has the potential to measure magnetic field pulses as high as a few hundred Oe without breaking down. In the proposed EMP detector, a magnetic field sensor is required to measure the surface field of the magnetic nanowire array. MgO based magnetic tunnel junction (MTJ) is one type of magnetic field sensors. We investigated the evolution of the magnetic transport properties as a function of short annealing time in MgO based MTJ junctions. It is found that the desired sensor behavior appears in samples annealed for 17 minutes. The result can be well fitted by using the superparamagnetism theory, suggesting the formation of superparamagnetic particles in the free layer during the high temperature annealing. The control of MTJ properties with annealing time is desirable in magnetic field sensor productions.
Author: Siva Yellampalli Publisher: BoD – Books on Demand ISBN: 1789233941 Category : Technology & Engineering Languages : en Pages : 220
Book Description
MEMS by becoming a part of various applications ranging from smartphones to automobiles has become an integral part of our everyday life. MEMS is building synergy between previously unrelated fields such as biology, microelectronics and communications, to improve the quality of human life. The sensors in MEMS gather information from the surrounding, which is then processed by the electronics for decision-making to control the environment. MEMS offers opportunities to miniaturize devices, integrate them with electronics and realize cost savings through batch fabrication. MEMS technology has enhanced many important applications in domains such as consumer electronics, biotechnology and communication and it holds great promise for continued contributions in the future. This book focuses on understanding the design, development and various applications of MEMS sensors.
Author: José Carlos Pedro Publisher: Cambridge University Press ISBN: 1108646417 Category : Technology & Engineering Languages : en Pages : 362
Book Description
Discover the nonlinear methods and tools needed to design real-world microwave circuits with this tutorial guide. Balancing theoretical background with practical tools and applications, it covers everything from the basic properties of nonlinear systems such as gain compression, intermodulation and harmonic distortion, to nonlinear circuit analysis and simulation algorithms, and state-of-the-art equivalent circuit and behavioral modeling techniques. Model formulations discussed in detail include time-domain transistor compact models and frequency-domain linear and nonlinear scattering models. Learn how to apply these tools to designing real circuits with the help of a power amplifier design example, which covers all stages from active device model extraction and the selection of bias and terminations, through to performance verification. Realistic examples, illustrative insights and clearly conveyed mathematical formalism make this an essential learning aid for both professionals working in microwave and RF engineering and graduate students looking for a hands-on guide to microwave circuit design.
Author: Aimad Saib
Author: Nicholas Kipplan Cramer
Author: Judith Spiegel
Author: Qi-jun Zhang
Author: Manuel Vázquez
Author: Filippo Capolino
Author: Xiaoming Kou
Author: Siva Yellampalli
Author: José Carlos Pedro
Author: