Download or read book Non foster Impedance Matching and Loading Networks for Electrically Small Antennas written by Keum Su Song and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Lastly, this dissertation discusses a method to improve the performance of a small loop antenna by using a Non-Foster inductor loading. The Non-Foster loading network (located away from the input port of the antenna) is employed to improve the impedance mismatch and also maintain an omni-directional antenna pattern at higher frequencies than the case of a loop antenna with a Non-Foster matching network and a short loading (stands for a small loop antenna). Although the experimental radiation patterns are somewhat different from the simulated data, it is found that the measured antenna gain and SNR with the Non-Foster inductor loading are improved when compared to case with a short loading. To the best of our knowledge, it is the first time that a fabricated Non-Foster impedance loading network was applied to an actual antenna.

Download or read book Antennas with Non Foster Matching Networks written by James T. Aberle and published by Morgan & Claypool Publishers. This book was released on 2007-12-01 with total page 53 pages. Available in PDF, EPUB and Kindle. Book excerpt: Most antenna engineers are likely to believe that antennas are one technology that is more or less impervious to the rapidly advancing semiconductor industry. However, as demonstrated in this lecture, there is a way to incorporate active components into an antenna and transform it into a new kind of radiating structure that can take advantage of the latest advances in analog circuit design. The approach for making this transformation is to make use of non-Foster circuit elements in the matching network of the antenna. By doing so, we are no longer constrained by the laws of physics that apply to passive antennas. However, we must now design and construct very touchy active circuits. This new antenna technology is now in its infancy. The contributions of this lecture are (1) to summarize the current state-of-the-art in this subject, and (2) to introduce some new theoretical and practical tools for helping us to continue the advancement of this technology.

Download or read book Small Antenna Handbook written by Robert C. Hansen and published by John Wiley & Sons. This book was released on 2011-08-26 with total page 362 pages. Available in PDF, EPUB and Kindle. Book excerpt: Now in an completely revised, updated, and enlarged Second Edition, Small Antennas in Portable Devices reviews recent significant theoretical and practical developments in the electrically small antenna area. Examining antenna designs that work as well as those that have limitations, this new edition provides practicing engineers and upper level and graduate students with new information on: work on improving bandwidth using spherical helix dipoles; work on electromagnetically coupled structures; exact derivation of the Q for electrically small antennas for both the TE and TM modes; and a new simplified Q formula.

Download or read book Non foster Impedances as Active Broadband Matching Networks for Electrically Small Antennas written by Robert L. Romak and published by . This book was released on 2006 with total page 244 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Design Methodology for Wideband Electrically Small Antennas ESA Based on the Theory of Characteristic Modes CM written by Khaled A. Obeidat and published by . This book was released on 2010 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Emerging broadband applications with market pressures for miniaturized communication devices have encouraged the use of electrically small antennas (ESA) and highly integrated RF circuitry for high volume low cost mobile devices. This research work focuses on developing a novel scheme to design wideband electrical small antennas that incorporates active and passive loading as well as passive matching networks. Several antennas designed using the proposed design technique and built and measured to assess their performance and to validate the design methodology. Previously, the theory of Characteristic Modes (CM) has been used mostly for antennas analysis. However; in this chapter a design procedure is proposed for designing wide band (both the input impedance bandwidth and the far field pattern bandwidth) electrically small to mid size antennas using the CM in conjunction with the theory of matching networks developed by Carlin. In order to increase the antenna gain, the antenna input impedance mismatch loss needs to be minimized by carefully exciting the antenna either at one port or at multiple ports and/or load the antenna at different ports along the antenna body such that the Q factor in the desired frequency range is suitable for wideband matching network design. The excitation (feeding structure), the loading of the antenna and/or even small modifications to the antenna structure can be modeled and understood by studying the eigenvalues and their corresponding eigencurrents obtained from the CM of the antenna structure. A brief discussion of the theory of Characteristic Modes (CM) will be presented and reviewed before the proposed design scheme is introduced. The design method will be used to demonstrate CM applications to widen the frequency bandwidth of the input impedance of an electrically small Vee shape Antenna and to obtain vertically polarized Omni-directional patterns for such antenna over a wide bandwidth. A loading technique based on the CM to either design frequency reconfigurable antennas or broaden their bandwidth by Non-Foster loading will also be discussed as part of the design methodology. In the Appendix, a brief discussion of the fundamental limits of electrical small antennas is presented and then followed by a discussion of the fundamental limits of the impedance bandwidth of the ESA when a passive matching network is used. Matching network implemented using Non-Foster matching is also discussed in the appendix.

Download or read book Electrically Small Superdirective and Superconducting Antennas written by R. C. Hansen and published by John Wiley & Sons. This book was released on 2006-06-19 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt: A seminal reference to electrically small antennas for today's wireless and Wi-Fi world This book is dedicated to the challenges posed by electrically small antennas and their solutions. Electrically small antennas have characteristics that limit performance: low radiation resistance, high reactance, low efficiency, narrow bandwidth, and increased loss in the matching network. Most of these limitations are shared by two other classes of antennas: superdirective and superconducting antennas. All three classes of antennas are thoroughly treated in three interrelated parts: * Part One, Electrically Small Antennas, begins with a discussion of the fundamental limitations of bandwidth and matching, then provides detailed design information on loaded whips and dipoles, ferrite loops, patches with unusual substrates, and dielectric resonator antennas. In addition to exploring designs that work, the author sets forth antenna designs that are based on good physics yet are poor performers, as well as designs with both poor underlying physics and poor performance. * Part Two, Superdirective Antennas, sets forth basic capabilities and limitations of superdirective antennas, both apertures and arrays, and investigates bandwidth, efficiency, and tolerances. The author explores the magnification of intrinsic matching circuit loss due to a large mismatch and evaluates the recent and promising non-Foster matching circuits. * Part Three, Superconducting Antennas, reviews superconductivity concepts and new principles for dipole, loop, and patch antennas. The author concludes with a discussion of superconducting delay lines for wideband phased array steering. Throughout the book, the author provides readers with a historical perspective, setting forth what has been investigated, what works, and what does not. Each part has its own author index and a list of references to help readers continue their explorations of particular topics.With the explosive demand for wireless and Wi-Fi, this seminal reference is essential reading for all antenna professionals and is recommended as a graduate-level course book.

Download or read book Automated Broad and Narrow Band Impedance Matching for RF and Microwave Circuits written by Amal Banerjee and published by Springer. This book was released on 2018-10-06 with total page 109 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents a seamless and unified scheme for automating very complicated calculations required to design, evaluate performance characteristics of, and implement broadband and narrow band impedance matching sub-circuits. The results of these automated calculations (the component values of the impedance matching sub-circuit) are formatted as text SPICE(Simulation Program with Integrated Circuit Emphasis) input netlists. Readers then immediately can use any available SPICE simulator to measure the performance characteristics (DC response, transient response, frequency response, RMS power transferred from source to load, reflection coefficient insertion and transmission loss, ans standing wave ratio – SWR). The text SPICE netlist can be edited easily to fine-tune the performance characteristics, and perform design space exploration and “what-if” type of analyses. Presents details of a coherent, logical and seamless scheme to design and measure the performance characteristics of both broad and narrow band impedance matching sub-circuits; Relieves the designer from having to manually do complex, multi-step(therefore error-prone and time-consuming) calculations, especially those related to broadband impedance matching sub-circuit design; Provides SPICE input netlists, which enable readers to use any available SPICE simulator to estimate the performance characteristics.

Download or read book Antenna Systems and Electronic Warfare Applications written by Richard Poisel and published by Artech House. This book was released on 2012 with total page 1060 pages. Available in PDF, EPUB and Kindle. Book excerpt: Antennas systems play a critical role in modern electronic warfare communications and radar. Today's EW engineers need to have a solid understanding of the design principles of this technology and how antenna systems are used in the field. This comprehensive book serves as a one-stop resource for practical EW antenna system know-how. Supported with over 700 illustrations and nearly 1,700 equations, this authoritative reference offers professionals detailed explanations of all the important foundations and aspects of this technology. Moreover, engineers get an in-depth treatment of a wide range of antenna system applications. The book presents the key characteristics of each type of antenna, including dipoles, monopoles, loops, arrays, horns, and patches. Practitioners also find valuable discussions on the limitations of antennas system performance in EW applications.

Download or read book Non foster Circuit Design and Stability Analysis for Wideband Antenna Applications written by Aseim M. N. Elfrgani and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In recent years, there has been a great interest in wide-band small antennas for wireless communication in both ground and airborne applications. Electrically small antennas; however, are narrow bandwidth since they exhibit high a quality factor (Q). Therefore, matching networks are required to improve their input impedance and radiation characteristics. Unfortunately, due to gain-bandwidth restrictions, wideband matching cannot be achieved using passive networks unless a high order matching network is used. Fortunately, the so-called non-Foster circuits (NFCs) employ active networks to bypass the well-known gain-bandwidth restrictions derived by Bode-Fano. Although NFCs can be very useful in numerous microwave and antenna applications, they are difficult to design because they are potentially instable. Consequently, an accurate and efficient systematic stability assessment is necessary during the design process to predict any undesired behavior. In this dissertation, the design, stability, and measurement of two non-Foster matching networks for two different small monopole antennas, a non-Foster circuit embedded within half loop antenna, a combination of Foster and non-Foster matching network for small monopole antenna are presented. A third circuit; namely, a non-Foster coupling network for a two-element monopole array is also presented for phase enhancement applications. It all examples, the NFCs substantially improve the antenna's performance over a wide frequency band.

Download or read book Characteristic Modes for Impedance Matching and Broadbanding of Electrically Small Antennas written by Jacob J. Adams and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Antennas smaller than a quarter wavelength are fundamentally constrained in a variety of ways. One of the more problematic limitations is that the antenna's bandwidth declines sharply as the size of the antenna decreases. Myriad studies have sought antennas that perform close to the fundamental limits, and they use a patchwork of good and bad design approaches. Our primary goal is to describe a new, complete framework to model the fundamental behavior of small antennas. We base our analysis in characteristic mode theory which allows us to decompose the antenna behavior into the behavior of a few well-defined modes. Using this decomposition we can better understand, design, and analyze small antennas. First, we explain a unified approach to model the antenna input impedance, rather than the haphazard array of approaches that are currently used. Using our model for the input impedance, we are then able to establish the conditions under which a small antenna can be effectively impedance matched, and analyze some simple methods for matching an antenna without using an external matching network. Through this study, we find that near-optimum modes actually exist in nearly every geometry but are often masked by higher order modes. From this result, a new design paradigm is proposed in which designs seek to couple into these existing modes and match using the simple methods described herein, rather than creating ever more complex and impractical structures. We also design and fabricate two novel, spherical, electrically small antennas, the TM10 antenna and the spherical meanderline antenna. Both of these antennas exhibit quality factor close to the lower limit, and hence, a near-optimum bandwidth. The spherical meanderline antenna is particularly well-suited for automated fabrication and can achieve bandwidth comparable to the best known values. In collaboration with materials scientists, we demonstrate the spherical meanderline antenna, which is one of the first microwave structures printed on a curved surface using a direct-ink write process. Finally, to circumvent some of the bandwidth limitations imposed on small antennas, we propose an approach to design multimode antennas. Estimates are derived for the bandwidth increases that can be achieved with this approach to antenna broadbanding, and a simple figure of merit is suggested. A case study in broadbanding the TM10 antenna provides some idea of what types of modal combinations are practical. Finally, a multimode spherical meanderline antenna matched with the simple techniques described herein is designed and fabricated.

Download or read book Automotive Mechanical and Electrical Engineering written by Lin Liu and published by CRC Press. This book was released on 2017-06-26 with total page 782 pages. Available in PDF, EPUB and Kindle. Book excerpt: The 2016 International Conference on Automotive Engineering, Mechanical and Electrical Engineering (AEMEE 2016) was held December 9-11, 2016 in Hong Kong, China. AEMEE 2016 was a platform for presenting excellent results and new challenges facing the fields of automotive, mechanical and electrical engineering. Automotive, Mechanical and Electrical Engineering brings together a wide range of contributions from industry and governmental experts and academics, experienced in engineering, design and research. Papers have been categorized under the following headings: Automotive Engineering and Rail Transit Engineering. Mechanical, Manufacturing, Process Engineering. Network, Communications and Applied Information Technologies. Technologies in Energy and Power, Cell, Engines, Generators, Electric Vehicles. System Test and Diagnosis, Monitoring and Identification, Video and Image Processing. Applied and Computational Mathematics, Methods, Algorithms and Optimization. Technologies in Electrical and Electronic, Control and Automation. Industrial Production, Manufacturing, Management and Logistics.

Download or read book Design and Applications of Active Integrated Antennas written by Mohammad S. Sharawi and published by Artech House. This book was released on 2018-05-31 with total page 280 pages. Available in PDF, EPUB and Kindle. Book excerpt: This comprehensive new resource guides professionals in the latest methods used when designing active integrated antennas (AIA) for wireless communication devices for various standards. This book provides complete design procedures for the various elements of such active integrated antennas such as the matching network, the amplifier/active element as well as the antenna. This book offers insight into how active integration and co-design between the active components (amplifier, oscillator, mixer, diodes) and the antenna can provide better power transfer, higher gains, increased efficiencies, switched beam patterns and smaller design footprints. It introduces the co-design approach of active integrated antennas and its superior performance over conventional methods. Complete design examples are given of active integrated antenna systems for narrow and wideband applications as well as for multiple-input-multiple-output (MIMO) systems. Readers find the latest design methods for narrow and broadband RF matching networks. This book provides a complete listing of performance metrics for active integrated antennas. The book serves as a complete reference and design guide in the area of AIA.

Download or read book Modern Small Antennas written by Kyohei Fujimoto and published by Cambridge University Press. This book was released on 2014-01-09 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: If you are involved in designing and developing small antennas, this complete cutting-edge guide covers everything you need to know. From fundamentals and basic theory to design optimization, evaluation, measurements and simulation techniques, all the essential information is included. You will also get many practical examples from a range of wireless systems, whilst a glossary is provided to bring you up to speed on the latest terminology. A wide variety of small antennas is covered, and design and practice steps are described for each type: electrically small, functionally small, physically constrained small and physically small. Whether you are a professional in industry, a researcher, or a graduate student, this is your essential guide to small antennas.

Download or read book Electrically Small Near Field Resonant Parasitic NFRP Antennas Augmented with Passive and Active Circuit Elements to Enhance Their Functionality written by Ning Zhu and published by . This book was released on 2013 with total page 308 pages. Available in PDF, EPUB and Kindle. Book excerpt: Metamaterials have drawn considerable attention because they can exhibit epsilon-negative (ENG) and/or mu-negative (MNG) properties, which in turn can lead to exotic physical effects that can enable interesting, practical applications. For instance, ENG and MNG properties can be engineered to yield double negative (DNG) properties, such as a negative index of refraction, which leads to flat lenses. Similarly, their extreme versions enable cloaking effects. Inspired by such metamaterial properties, a promising methodology has been developed to design electrically small antennas (ESAs). These ESAs use unit cells of metamaterials as their near-field resonant parasitic (NFRP) elements. This new metamaterial-inspired antenna miniaturization method is extended in this dissertation by augmenting the antenna designs with circuits. A rectifying circuit augmentation is used to achieve electrically small, high efficiency rectenna systems. Rectennas are the enabling components of power harvesting and wireless power transmission systems. Electrically small, integrated rectennas have become popular and in demand for several wireless applications including sensor networks and bio-implanted devices. Four global positioning system (GPS) L1 frequency (1.5754 GHz) rectenna systems were designed, fabricated and measured: three resistor-loaded and one supercapacitor-loaded. The simulated and measured results will be described; good agreement between them was obtained. The NFRP ESAs are also augmented with active, non-Foster elements in order to overcome the physical limits of the impedance bandwidth of passive ESA systems. Unlike conventional active external matching network approaches, the non-Foster components are incorporated directly into the NFRP element of the ESA. Three 300 MHz non-Foster circuit-augmented broadband, ESA systems were demonstrated: an Egyptian axe monopole (EAM) antenna, an Egyptian axe dipole (EAD) antenna, and a protractor antenna. The simulated and measured results will be described; reasonable agreement between them was obtained. Moreover, a deeper practical engineering understanding of how lumped components with tighter tolerances, more accurate transistor models, and integrated circuit-based implementations will lead to more satisfactory performance characteristics of the non-Foster circuit-augmented ESAs was accomplished and is also reported.

Download or read book The Physics and Mathematics of Electromagnetic Wave Propagation in Cellular Wireless Communication written by Tapan K. Sarkar and published by John Wiley & Sons. This book was released on 2018-05-31 with total page 520 pages. Available in PDF, EPUB and Kindle. Book excerpt: An important resource that examines the physical aspects of wireless communications based on mathematical and physical evidence The Physics and Mathematics of Electromagnetic Wave Propagation in Cellular Wireless Communicationdescribes the electromagnetic principles for designing a cellular wireless system and includes the subtle electromagnetic principles that are often overlooked in designing such a system. This important text explores both the physics and mathematical concepts used in deploying antennas for transmission and reception of electromagnetic signals and examines how to select the proper methodology from a wide range of scenarios. In this much-needed guide, the authors—noted experts in the field—explore the principle of electromagnetics as developed through the Maxwellian principles and describe the properties of an antenna in the frequency domain. The text also includes a review of the characterization of propagation path loss in a cellular wireless environment and examines ultrawideband antennas and the mechanisms of broadband transmission of both power and information. This important resource: Includes a discussion of the shortcomings of a MIMO system from both theoretical and practical aspects Demonstrates how to deploy base station antennas with better efficiency Validates the principle and the theoretical analysis of electromagnetic propagation in cellular wireless communication Contains results of experiments that are solidly grounded in mathematics and physics Written for engineers, researchers, and educators who are or plan to work in the field, The Physics and Mathematics of Electromagnetic Wave Propagation in Cellular Wireless Communicationoffers an essential resource for understanding the principles underpinning wireless communications.

Download or read book Broadband Impedance Matching of Antenna Radiators written by Vishwanath Iyer and published by . This book was released on 2010 with total page 408 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: In the design of any antenna radiator, single or multi-element, a significant amount of time and resources is spent on impedance matching. There are broadly two approaches to impedance matching; the first is the distributed impedance matching approach which leads to modifying the antenna geometry itself by identifying appropriate degrees of freedom within the structure. The second option is the lumped element approach to impedance matching. In this approach instead of modifying the antenna geometry a passive network attempts to equalize the impedance mismatch between the source and the antenna load. This thesis introduces a new technique of impedance matching using lumped circuits (passive, lossless) for electrically small (short) non-resonant dipole/monopole antennas. A closed form upper-bound on the achievable transducer gain (and therefore the reflection coefficient) is derived starting with the Bode-Fano criterion. A 5 element equalizer is proposed which can equalize all dipole/monopole like antennas. Simulation and experimental results confirm our hypothesis. The second contribution of this thesis is in the design of broadband, small size, modular arrays (2, 4, 8 or 16 elements) using the distributed approach to impedance matching. The design of arrays comprising a small number of elements cannot follow the infinite array design paradigm. Instead, the central idea is to find a single optimized radiator (unit cell) which if used to build the 2x1, 4x1, 2x2 arrays, etc. (up to a 4x4 array) will provide at least the 2:1 bandwidth with a VSWR of 2:1 and stable directive gain (not greater than 3 dB variation) in each configuration. Simulation and experimental results for a solution to the 2x1, 4x1 and 2x2 array configurations is presented.

Download or read book Microwave Filters Impedance matching Networks and Coupling Structures written by George L. Matthaei and published by . This book was released on 1964 with total page 1134 pages. Available in PDF, EPUB and Kindle. Book excerpt: