Download or read book Improvement of Performance Characteristics of a Class of Broadband Circularly Polarized Antennas written by ANTENNA CORP OF AMERICA HARLEYSVILLE PA. and published by . This book was released on 1972 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt: The report covers a development program for the improvement of performance characteristics of a class of broadband circularly polarized antennas for use with tactical airborne jamming equipment. A historical record of the program, testing procedures, significant results, conclusions, and recommendations are covered. (Author).

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1985 with total page 1346 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Circularly Polarized Antenna Technology written by and published by Walter de Gruyter GmbH & Co KG. This book was released on 2020-11-23 with total page 353 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book presents basic and advanced concepts of circularly polarized antennas, including design procedure and recent applications. Cross dipole antennas, microstrip antennas, helical antennas, quadrifilar helix antennas, frequency independent antennas, horn antennas, omnidirectional circularly polarized antennas and radial line arry antennas are discussed. With abundant examples, the book is an essential reference for researchers and engineers.

Download or read book Performance Enhancement of Radiation and Scattering Properties of Circularly Polarized Antennas Using Frequency Selective Surface written by Mohammad Akbari Choubar and published by . This book was released on 2018 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt: At millimetre-wave (MMW) frequencies, losses associated with wireless link and system are critical issues that need to be overcome in designing high-performance wireless systems. To compensate the overall loss in a wireless communication system, a high-gain antenna is required. Circularly polarized (CP) antennas are among preferred choices to design because they offer many advantages due to their good resistance to polarization mismatch, mitigation of multipath effects, and some phasing issues and immunity to Faraday rotation. On the other hand, frequency selective surface (FSS) technology is recently employed to enhance the performance of radiation and scattering properties of antennas used in different sectors such as aerospace, medical, and microwave industry. Therefore, it is appropriate and attractive to propose the use of FSS technology to design practical and efficient CP antennas. CP Fabry-Perot cavity (FPC) antennas based on FSS are investigated in this thesis to fulfil the growing demand for broadband high-gain antennas with low radar cross section (RCS). The thesis investigates both characteristic improvement of CP antennas and RCS reduction issues employing FSS structures. Initially, a high gain CP dielectric resonator (DR) antenna is proposed. Using an FSS superstrate layer, a gain enhancement of 8.5 dB is achieved. A detailed theoretical analysis along with different models are presented and used to optimize the superstrate size and the air gap height between the antenna and superstrate layer. The second research theme focusses on developing an effective approach for mitigating the near-field coupling between four-port CP antennas in a Multiple-Input, Multiple-Output (MIMO) system. This is obtained by incorporating a two-layer transmission-type FSS superstrate based on planar crossed-dipole metal strips. Another technique for suppressing the spatially coupling between DR antennas using a new FSS polarization-rotator wall is studied as well. The coupling reduction is achieved by embedding an FSS wall between two DRAs, which are placed in the H-plane. Utilizing this FSS wall, the TE modes of the antennas become orthogonal, which reduces the spatially coupling between the two DRAs. The third research theme of this thesis is to enhance the purity and bandwidth of CP with the least amount of insertion loss by the use of an LP-to-CP-polarizer which is based on multilayer FSS slab. This polarizer is approximately robust under oblique illuminations. To have a high-gain CP antenna, an 8-element LP array antenna with Chebyshev tapered distribution is designed and integrated with the polarizer. Eventually, in order to enhance the scattering property, the fourth research theme investigates on RCS reduction by the use of two different approaches which are based on FSS. Initially, a wideband FSS metasurface for RCS reduction based on a polarization conversion is proposed. To distribute the scattered EM waves and suppress the maximum bistatic RCS of the metasurface over a broad band of incident angles at both polarizations, the elements are arranged using the binary coding matrix achieved by group search optimization (GSO) algorithm. The reflective two-layer metasurface is designed in such a way to generate reflection phase difference of 180° between two elements "0" and "1" on a broad frequency band. A theoretical analysis is performed on the ratio of the "0" and "1" elements using Least Square Error (LSE) method to find the best ratio value. As the second activity of this research theme, wideband CP antenna with low RCS and high gain properties is presented. The proposed antenna is based on a combination of the FPC and sequential feeding technique.

Download or read book Aeronautical Engineering written by and published by . This book was released on 1974 with total page 770 pages. Available in PDF, EPUB and Kindle. Book excerpt: A selection of annotated references to unclassified reports and journal articles that were introduced into the NASA scientific and technical information system and announced in Scientific and technical aerospace reports (STAR) and International aerospace abstracts (IAA).

Download or read book Government Reports Announcements written by and published by . This book was released on 1973 with total page 1726 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Electronic Countermeasures and Electronic Counter Countermeasures written by United States. National Technical Information Service and published by . This book was released on 1976 with total page 280 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Government Reports Announcements Index written by and published by . This book was released on 1975-06 with total page 682 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Innovative Antenna Designs for Broadband Circularly Polarized Wireless Systems and Software Radios written by Joshua Kovitz and published by . This book was released on 2015 with total page 347 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sustaining current increases in wireless data rates has driven engineers of all related backgrounds to seek fresh and innovative approaches in wireless system design. With the advancement of RF switching technology, transceiver architectures, and digital signal processing capabilities, the pressure now falls on the antenna designs for future broadband and adaptive wireless services. The rst part of the work focuses on enhancing the bandwidth of low-pro le patch antennas for circularly-polarized (CP) wireless systems. We start with an in-depth examination of the CP patch antenna cavity model and reveal that traditional circularly polarized (CP) patch antennas are not being utilized to their full potential for bandwidth. Some new modi cations to enable broader bandwidths are proposed. A high-performance antenna for future Mars Rover missions is also discussed, and a novel CP Half E-shaped patch antenna subarray was developed and prototyped to demonstrate its use. Another concept uses composite right/left-handed (CRLH) transmission lines towards creating wideband CP arrays. Our resulting array prototype using a CRLH transmission line feed network showed an overall bandwidth of 60%, which is a formidable increase compared to designs using conventional quarter-wavelength transmission lines. In the second part of this work, recon gurable antenna functionalities for software and cognitive radios are pursued. With the development of practical recon gurable antenna simulation models in conjunction with nature-inspired optimization techniques, two recon gurable E-shaped patch antenna implementations are evaluated for potential use as frequency or polarization recon gurable antennas. This is particularly useful for systems wanting to achieve unidirectional patterns with a low-pro le antenna. Both the frequency and polarization recon gurable designs were optimized, fabricated, and characterized through measurement. Our frequency recon gurable E-shaped patch antenna design is able to support an overall bandwidth of 50% by incorporating MEMS switches. The CP recon gurable version design provided CP bandwidths of 17% and 20% for an element and array concept, respectively. Lastly, a rejection recon gurable array element is developed. The design uses a recon gurable frequency rejection slot within a wideband monopole antenna, and some simulation and experimental measurement studies are undertaken. By integrating another recon gurable lter, a higher-order lter capability is achieved, leading to stronger rejection levels from strong blockers.

Download or read book Space Antenna Handbook written by William A. Imbriale and published by John Wiley & Sons. This book was released on 2012-06-25 with total page 772 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book addresses a broad range of topics on antennas for space applications. First, it introduces the fundamental methodologies of space antenna design, modelling and analysis as well as the state-of-the-art and anticipated future technological developments. Each of the topics discussed are specialized and contextualized to the space sector. Furthermore, case studies are also provided to demonstrate the design and implementation of antennas in actual applications. Second, the authors present a detailed review of antenna designs for some popular applications such as satellite communications, space-borne synthetic aperture radar (SAR), Global Navigation Satellite Systems (GNSS) receivers, science instruments, radio astronomy, small satellites, and deep-space applications. Finally it presents the reader with a comprehensive path from space antenna development basics to specific individual applications. Key Features: Presents a detailed review of antenna designs for applications such as satellite communications, space-borne SAR, GNSS receivers, science instruments, small satellites, radio astronomy, deep-space applications Addresses the space antenna development from different angles, including electromagnetic, thermal and mechanical design strategies required for space qualification Includes numerous case studies to demonstrate how to design and implement antennas in practical scenarios Offers both an introduction for students in the field and an in-depth reference for antenna engineers who develop space antennas This book serves as an excellent reference for researchers, professionals and graduate students in the fields of antennas and propagation, electromagnetics, RF/microwave/millimetrewave systems, satellite communications, radars, satellite remote sensing, satellite navigation and spacecraft system engineering, It also aids engineers technical managers and professionals working on antenna and RF designs. Marketing and business people in satellites, wireless, and electronics area who want to acquire a basic understanding of the technology will also find this book of interest.

Download or read book Government Reports Index written by and published by . This book was released on 1973 with total page 962 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Circularly Polarized Antennas written by Steven Shichang Gao and published by John Wiley & Sons. This book was released on 2014-02-03 with total page 341 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents a comprehensive insight into the design techniques for different types of CP antenna elements and arrays In this book, the authors address a broad range of topics on circularly polarized (CP) antennas. Firstly, it introduces to the reader basic principles, design techniques and characteristics of various types of CP antennas, such as CP patch antennas, CP helix antennas, quadrifilar helix antennas (QHA), printed quadrifilar helix antennas (PQHA), spiral antenna, CP slot antennas, CP dielectric resonator antennas, loop antennas, crossed dipoles, monopoles and CP horns. Advanced designs such as small-size CP antennas, broadband, wideband and ultra-wideband CP antennas are also discussed, as well as multi-band CP antennas and dual CP antennas. The design and analysis of different types of CP array antennas such as broadband CP patch arrays, dual-band CP arrays, CP printed slot arrays, single-band and multi-band CP reflectarrays, high-gain CP waveguide slot antennas, CP dielectric resonator antenna arrays, CP active arrays, millimetre-waveband CP arrays in LTCC, and CP arrays with electronically beam-switching or beam-steering capabilities are described in detail. Case studies are provided to illustrate the design and implementation of CP antennas in practical scenarios such as dual-band Global Navigation Satellite Systems (GNSS) receivers, satellite communication mobile terminals at the S-band, Radio Frequency Identification (RFID) readers at 2.4 GHz, and Ka-band high-speed satellite communication applications. It also includes the detailed designs for a wideband Logarithmic spiral antenna that can operate from 3.4-7.7 GHz. In addition, the book offers a detailed review of the recent developments of different types of CP antennas and arrays. Presents comprehensive discussions of design techniques for different types of CP antennas: small-size CP antennas, broadband CP antennas, multi-band CP antennas and CP arrays. Covers a wide range of antenna technologies such as microstrip antennas, helix, quadrifilar helix antenna, printed quadrifilar helix antenna, dielectric resonator antennas, printed slots, spiral antennas, monopoles, waveguide slot arrays, reflectarrays, active arrays, millimetre-wave arrays in LTCC, electronically beam-switching arrays and electronically beam-steerable arrays. Reviews recent developments in different types of CP antennas and arrays, reported by industries, researchers and academics worldwide. Includes numerous case studies to demonstrate how to design and implement different CP antennas in practical scenarios. Provides both an introduction for students in the field and an in-depth reference for antenna/RF engineers who work on the development of CP antennas. Circularly Polarized Antennas will be an invaluable guide for researchers in R&D organizations; system engineers (antenna, telecom, space and satellite); postgraduates studying the subjects of antenna and propagation, electromagnetics, RF/microwave/millimetre-wave systems, satellite communications and so on; technical managers and professionals in the areas of antennas and propagation.

Download or read book Artificial Intelligence and Data Science in Environmental Sensing written by Mohsen Asadnia and published by Academic Press. This book was released on 2022-02-09 with total page 326 pages. Available in PDF, EPUB and Kindle. Book excerpt: Artificial Intelligence and Data Science in Environmental Sensing provides state-of-the-art information on the inexpensive mass-produced sensors that are used as inputs to artificial intelligence systems. The book discusses the advances of AI and Machine Learning technologies in material design for environmental areas. It is an excellent resource for researchers and professionals who work in the field of data processing, artificial intelligence sensors and environmental applications. Presents tools, connections and proactive solutions to take sustainability programs to the next level Offers a practical guide for making students proficient in modern electronic data analysis and graphics Provides knowledge and background to develop specific platforms related to environmental sensing, including control water, air and soil quality, water and wastewater treatment, desalination, pollution mitigation/control, and resource management and recovery

Download or read book Conference Proceedings written by and published by . This book was released on 1959 with total page 520 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Digest written by IEEE Antennas and Propagation Society. International Symposium and published by . This book was released on 2001 with total page 908 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Electrical Electronics Abstracts written by and published by . This book was released on 1997 with total page 1948 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Electromagnetic Band Gap Structures in Antenna Engineering written by Fan Yang and published by Cambridge University Press. This book was released on 2009 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a detailed account of electromagnetic band gap (EBG) theory, analysis and applications, ideal for researchers and engineers.