Download or read book Microstrip Antennas with Polarization Diversity Across a Wide Frequency Range and Phased Array Antennas for Radar and Satellite Communications written by Kevin Ming-Jiang Ho and published by . This book was released on 2015 with total page 169 pages. Available in PDF, EPUB and Kindle. Book excerpt: The thesis comprises of 3 projects; an L-band microstrip antenna with frequency agility and polarization diversity, X-band phased array antennas incorporating commercially packaged RFIC phased array chips, and studies for Ku/Ka-band shared aperture antenna array. The first project features the use of commercially packaged RF-MEMS SPDT switches, that boasts of high reliability, high linearity, low losses, hermetically packaged and fully compatible for SMTA processes for mass-assembly and production. Using the switches in a novel manner for the feed network, microstrip antennas with polarization diversity are presented. Frequency agility is achieved with the use of tuning diodes to provide capacitive loading to the antenna element. Additional inductance effects from surface-mounted capacitors, and its impact, is introduced. Theoretical cross-polarization of probe-fed antenna elements is presented for both linear and circular polarized microstrip antennas. Designs and measurements are presented, for microstrip antennas with polarization diversity, wide frequency tuning range, and both features. Replacement of the tuning diodes with commercially-packaged high Q RF MEMS tunable capacitors will allow for significant improvements to the radiation efficiency. In another project, multi-channel CMOS RFIC phased-array receiver chips are assembled in QFN packages and directly integrated on the same multi-layered PCB stack-up with the antenna arrays. Problems of isolation from the PCB-QFN interface, and potential performance degradation on antenna array from the use of commercial-grade laminates for assembly requirements, namely potential scan blindness and radiation efficiency, are presented. Causes for apparent drift of dielectric constant for microstrip circuits, and high conductor losses observed in measurements, are introduced. Finally, studies are performed for the design of a Ku/Ka-Band shared aperture array. Different approaches for developing dual-band shared apertures are considered. Design for single-fed circular-polarized dual-band antenna element operating at 20 GHz and 30 GHz is presented. Designs for dual-band quadrature and differential phased 3dB couplers are presented. Studies are performed on cross-polarization performances of circularly-polarized microstrip antenna arrays resulting from performance limitations of individual antenna elements. Results of the pattern studies and designs of the dual-band components can be combined to evaluate practical performance of dual-band array implementation and required component specifications and bandwidth constraints.

Download or read book Novel Microstrip Patch Antennas with Frequency Agility Polarization Reconfigurablity Dual Null Steering Capability and Phased Array Antenna with Beam Steering Performance written by and published by . This book was released on 2016 with total page 208 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nowadays the wireless communication technology is playing an important role in our daily life. People use wireless devices not only as a conventional communication device but also as tracking and navigation tool, web browsing tool, data storage and transfer tool and so for many other reasons. Based on the user demand, wireless communication engineers try to accommodate as many as possible wireless systems and applications in a single device and therefore, creates a multifunctional device. Antenna, as an integral part of any wireless communication systems, should also be evolved and adjusted with development of wireless transceiver systems. Therefore multifunctional antennas have been introduced to support and enhance the functionality on modern wireless systems. The main focus and contribution of this thesis is design of novel multifunctional microstrip antennas with frequency agility, polarization reconfigurablity, dual null steering capability and phased array antenna with beam steering performance. In this thesis, first, a wide bandwidth(1.10 GHz to 1.60 GHz) right-handed circularly polarized (RHCP) directional antenna for global positioning system (GPS) satellite receive application has been introduced which covers all the GPS bands starting from L1 to L5. This design consists of two crossed bow-tie dipole antennas fed with sequentially phase rotated feed network backed with an artificial high impedance surface (HIS) structure to generate high gain directional radiation patterns. This design shows good CP gain and axial ratio (AR) and wide beamwidth performance. Although this design has good radiation quality, the size and the weight can be reduced as future study. In the second design, a frequency agile antenna was developed which also covers the L-band (L1 to L5) satellite communication frequencies. This frequency agile antenna was designed and realized by new implementation of varactor diodes in the geometry of a circular patch antenna. Beside wide frequency agility (1.17 GHz to 1.58 GHz), full polarization reconfiguration was added to the design by controlling ports excitation of circular patch using RF switches (vertical linear, horizontal linear, right-handed circular polarization (RHCP) and left-handed circular polarization (LHCP)). This deign maintains good gain and radiation efficiency over the tunable range as well as acceptable co-polarization and cross-polarization separation for different polarizations. Since many communications applications require beam steering ability, in our third design, we designed and developed a linear phased array antenna using a modified version of our frequency agile polarization reconfigurable antenna for beam steering applications. This design offers wide frequency agility (1.50 GHz to 2.40 GHz), full polarization reconfiguration (vertical linear, horizontal linear, LHCP and RHCP) as well as beam steering of ±52° and ±28° at 1.5 GHz and 2.4 GHz, respectively. In this 1×4 array, the excitation magnitude and phase of each element was controlled by an analog beamforming feed network (BFN) for beam steering purposes. The required excitation for each element to steer the beam toward a desired location was calculated using projection matrix method (PMM) which uses measured active element pattern (AEP) as its input. This array antenna performance for frequency agility, radiation quality for each polarization and beam steering capability was obtained in the acceptable range. In the last design, the full spherical dual null steering capability of a triple mode circular microstrip patch antenna was investigated. By combining the radiation patterns of three individual modes of microstrip circular patch antenna, two nulls have been generated. These nulls can be repositioned in the upper hemisphere by controlling excitation ratio of each mode. The modes excitation ratio to steer the nulls toward the desired positions was calculated using a derivative free hybrid optimization method. This optimization method uses particle swarm optimization (PSO) combined with pattern search (PS) to find the optimum modes excitation ratio which minimizes the received power at the null positions. The calculated coefficients were applied to the multimode antenna using an analog BFN. This design shows an independent dual null steering with null depth of around 20 dB. Discussion about the proposed antennas included detailed theoretical analysis, numerical simulation and optimizations, beam forming and null steering algorithms, fabrication of the antennas and its control/beamforming feed networks along with the associated bias networks, microcontroller units, and finally its characterization (impedance matching, gain and 2D and 3D radiation patterns). The research work was performed at the Antenna and Microwave Lab (AML) which has the required resources including full wave analysis tools, PCB milling machine, surface mount component soldering station, vector network analyzers, and far-field/spherical near-field radiation pattern measurement system.

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 704 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Microstrip Antennas written by N Nasimuddin and published by BoD – Books on Demand. This book was released on 2011-04-04 with total page 556 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the last 40 years, the microstrip antenna has been developed for many communication systems such as radars, sensors, wireless, satellite, broadcasting, ultra-wideband, radio frequency identifications (RFIDs), reader devices etc. The progress in modern wireless communication systems has dramatically increased the demand for microstrip antennas. In this book some recent advances in microstrip antennas are presented.

Download or read book Design of Stripline fed Dual Polarization Aperture coupled Stacked Microstrip Patch Phased Array Antenna for Wideband Application written by David G. Kim and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent days, antennas play an important role in wireless communication system. Microstrip patch antennas are well known to have positive features for cost-effective, low profile and broadband. This type of antenna can be used in wide range of applications such as in wireless communications, radar systems, and satellites. Inhibiting characteristics of single patch antenna with low gain and narrow band leads to the research area to have array configuration. Beam steering antennas are the ideal solution for various systems such as traffic control and collision avoidance radar systems. The goal of this work is to design and implement a dual-linear polarization stacked microstrip patch phased array antenna. Single stacked microstrip patch antenna fed by microstrip line was designed to have approximately 3 GHz bandwidth in X-band with another ground plane to form a stripline-fed. Stripline-fed design protects feed lines from any outside effects. The array configuration was adapted to design in order to accomplish beam scan angle of /- 30 degrees by /- 15 degrees. Binomial power distribution of 3x2 array structure was used in order to reduce grating lobes, and changing length of feed lines was implemented for phase shifting. Bowtie cross shape aperture and dual-offset microstrip feedline was used to feed radiating patches. For the feed network, T-split power divider was implemented and optimized to achieve low loss. The length of microstrip line was adjusted to meet desired phase shift that in wideband application, the length of the line had to be long enough to have similar wavelength response over broad frequency range. The antenna array was designed using standard equations and simulated by electromagnetic analysis software called Zealand's IE3D which is method-of-moments based simulator. The resulting measured impedance bandwidth and gain of both microstrip and stripline-fed single antenna are 43 percent and 5 to 10 dBi with low cross polarizations for all frequencies. The array antenna was measured to have 29 to 60 percent impedance bandwidths depending on the different types of beam scan angles. The gain of the array antenna is 8 to 13 dBi, and the beams are directed as required with /- 3 degrees beam scan angle tolerance. The array antenna had a small offset as compared with simulated results because of the fabrication process such as alignment, distorted feed lines while etching, and etc, but the bandwidths and array patterns were acceptable.

Download or read book Reconfigurable Antenna Design and Analysis written by Mohammod Ali and published by Artech House. This book was released on 2021-05-31 with total page 310 pages. Available in PDF, EPUB and Kindle. Book excerpt: This exciting new book focuses on the analysis and design of reconfigurable antennas for modern wireless communications, sensing, and radar. It presents the definitions of basic antenna parameters, an overview of RF switches and explains how to characterize their insertion loss, isolation, and power handling issues. Basic reconfigurable antenna building blocks, such as dipoles, monopoles, patches and slots are described, followed by presentations on frequency reconfigurable antennas, pattern reconfigurable antennas, and basic scanning antenna arrays. Switch biasing in an electromagnetic environment is discussed, as well as simulation strategies of reconfigurable antennas, and MIMO (Multiple Input Multiple Output) reconfigurable antennas. Performance characterization of reconfigurable antennas is also presented. The book provides information for the technical professional to design frequency reconfigurable, pattern reconfigurable, and MIMO antennas all relevant for modern wireless communication systems. Readers learn how to select switching devices, bias them properly, and understand their role in the overall reconfigurable antenna design. The book presents practical experimental implementation issues, including losses due to switches, materials, and EMI (Electromagnetic Interference) and shows how to address those.

Download or read book Japanese Science and Technology 1983 1984 written by United States. National Aeronautics and Space Administration. Scientific and Technical Information Branch and published by . This book was released on 1985 with total page 1080 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Large Deployable Satellite Antennas written by Baoyan Duan and published by Springer Nature. This book was released on 2020-06-29 with total page 282 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book discusses the innovative design, cable-net design and analysis, control, deployment, development and applications of large space-deployable antennas. Drawing on the authors’ own work in this field, it describes and analyzes various typical deployable antennas, membrane antennas and super-large space-assembled antennas, while chiefly focusing on mesh antennas due to their wide range of applications. It also investigates forming–finding design and the analysis of cable-truss structures for high-precision reflector antennas, as well as deployment process control and deployment reliability based on flexible multibody dynamic analysis. The book covers not only mechanical structure performance, but also electromagnetic performance realization and stability. Lastly, it proposes an electrical equivalent method for mesh reflector antennas and a coupling model for the structural displacement field and electrostatic field. Given the nature of its content, the book is intended for researchers, graduate students and engineers in the field of space antennas.

Download or read book Air Force Systems Command Research Planning Guide written by and published by . This book was released on 1984-02 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Handbook of Microstrip Antennas written by James R. James and published by . This book was released on 1989 with total page 864 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book reviews developments in the following fields:circular microstrip antennas; microstrip patch antennas; circular polarisation and bandwidth; microstrip dipoles; multilayer and parasitic configurations; wideband flat dipole and short-circuit microstrip patch elements and arrays; numerical analysis; multiport network approach; transmission-line model; rectangular microstrip antennas; low-cost printed antennas; printed phased-array antennas; circularly polarised antenna arrays; microstrip antenna feeds; substrate technology; computer-aided design of microstrip and triplate circuits; resonant microstrip antenna elements and arrays for aerospace applications; mobile and satellite systems; conical conformal microstrip tracking antenna; and microstrip field diagnostics.

Download or read book International Aerospace Abstracts written by and published by . This book was released on 1999 with total page 974 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The 20 Ghz Circularly Polarized High Temperature Superconducting Microstrip Antenna Array written by National Aeronautics and Space Adm Nasa and published by . This book was released on 2018-11-12 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt: The primary goal was to design and characterize a four-element, 20 GHz, circularly polarized microstrip patch antenna fabricated from YBa2Cu3O(x) superconductor. The purpose is to support a high temperature superconductivity flight communications experiment between the space shuttle orbiter and the ACTS satellite. This study is intended to provide information into the design, construction, and feasibility of a circularly polarized superconducting 20 GHz downlink or cross-link antenna. We have demonstrated that significant gain improvements can be realized by using superconducting materials for large corporate fed array antennas. In addition, we have shown that when constructed from superconducting materials, the efficiency, and therefore the gain, of microstrip patches increases if the substrate is not so thick that the dominant loss mechanism for the patch is radiation into the surface waves of the conductor-backed substrate. We have considered two design configurations for a superconducting 20 GHz four-element circularly polarized microstrip antenna array. The first is the Huang array that uses properly oriented and phased linearly polarized microstrip patch elements to realize a circularly polarized pattern. The second is a gap-coupled array of circularly polarized elements. In this study we determined that although the Huang array operates well on low dielectric constant substrates, its performance becomes extremely sensitive to mismatches, interelement coupling, and design imperfections for substrates with high dielectric constants. For the gap-coupled microstrip array, we were able to fabricate and test circularly polarized elements and four-element arrays on LaAlO3 using sputtered copper films. These antennas were found to perform well, with relatively good circular polarization. In addition, we realized a four-element YBa2Cu3O(x) array of the same design and measured its pattern and gain relative to a room temperature copper array. The patterns were essentia...

Download or read book Electrical Electronics Abstracts written by and published by . This book was released on 1997 with total page 1860 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book IMDC SDSP 2020 written by Raed Abd-Alhameed and published by European Alliance for Innovation. This book was released on 2020-09-09 with total page 1619 pages. Available in PDF, EPUB and Kindle. Book excerpt: IMDC-SDSP conference offers an exceptional platform and opportunity for practitioners, industry experts, technocrats, academics, information scientists, innovators, postgraduate students, and research scholars to share their experiences for the advancement of knowledge and obtain critical feedback on their work. The timing of this conference coincides with the rise of Big Data, Artificial Intelligence powered applications, Cognitive Communications, Green Energy, Adaptive Control and Mobile Robotics towards maintaining the Sustainable Development and Smart Planning and management of the future technologies. It is aimed at the knowledge generated from the integration of the different data sources related to a number of active real-time applications in supporting the smart planning and enhance and sustain a healthy environment. The conference also covers the rise of the digital health, well-being, home care, and patient-centred era for the benefit of patients and healthcare providers; in addition to how supporting the development of a platform of smart Dynamic Health Systems and self-management.

Download or read book Wideband Phased Array Antennas and Compact Harmonic suppressed Microstrip Filters written by Wen-Hua Tu and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Modern satellite, wireless communications, and radar systems often demand wideband performance for multi-channel and multi-function operations. Among these applications, phased array antennas play an important role. This dissertation covers two wideband phased array antennas, one produces linear polarization and one produces circular polarization. The main difference between these two phased array antennas is the antenna array. For the linearly polarized array, a wideband microstrip line to slotline transition is used to feed a Vivaldi antenna. For the circularly polarized array, a wideband microstrip line to parallel stripline transition is used to feed a spiral antenna. From 3 to 12 GHz, the linearly polarized beam is steered over "15°. Since the electromagnetic spectrum is limited and has to be shared, interference is getting serious as more and more wireless applications emerge. Filters are key components to prevent harmonic interference. The harmonic signals can be suppressed by cascading additional lowpass filters or bandstop filters. A bandstop filter combining shunt open stubs and a spurline is proposed for a compact size and a deeper rejection. Two lowpass filters with interdigital capacitors and slotted ground structures are also studied. Harmonic suppression can also be achieved with the modification of bandpass filters. Three conventional bandpass filters with spurious passbands are investigated. The first one is a dual-mode patch bandpass filter. The second passband of the proposed filter is at 2.88f0, where f0 is the fundametal frequency. The second filter is an open-loop bandpass filter. Two open stubs are added to achieve high suppression in the second harmonic signal. The suppression of 35 dB at the second harmonic is obtained. For the third filter using half-wavelength open stubs, a T-shaped line is used to replace the quarter-wavelength connecting line. The T-shaped line has the same response with the connecting line in the passband. Furthermore, the T-shaped line works as a bandstop filter at the second harmonic. Finally, a new compact slow-wave resonator and bandpass filters are presented. A simple transmission-line model is used to predict the resonant frequency. Compared with the conventional uniform half-wavelength resonator, the slow-wave resonator shows a 25% size reduction.

Download or read book Spaceborne Antennas for Planetary Exploration written by William A. Imbriale and published by John Wiley & Sons. This book was released on 2006-08-04 with total page 594 pages. Available in PDF, EPUB and Kindle. Book excerpt: JPL spacecraft antennas-from the first Explorer satellite in 1958 to current R & D Spaceborne Antennas for Planetary Exploration covers the development of Jet Propulsion Laboratory (JPL) spacecraft antennas, beginning with the first Explorer satellite in 1958 through current research and development activities aimed at future missions. Readers follow the evolution of all the new designs and technological innovations that were developed to meet the growing demands of deep space exploration. The book focuses on the radio frequency design and performance of antennas, but covers environmental and mechanical considerations as well. There is additionally a thorough treatment of all the analytical and measurement techniques used in design and performance assessment. Each chapter is written by one or more leading experts in the field of antenna technology. The presentation of the history and technology of spaceborne antennas is aided by several features: * Photographs and drawings of JPL spacecraft * Illustrations to help readers visualize concepts and designs * Tables highlighting and comparing the performance of the antennas * Bibliographies at the end of each chapter leading to a variety of primary and secondary source material This book complements Large Antennas of the Deep Space Network (Wiley 2002), which surveys the ground antennas covered in support of spacecraft. Together, these two books completely cover all JPL antenna technology, in keeping with the JPL Deep Space Communications and Navigation Series mission to capture and present the many innovations in deep space telecommunications over the past decades. This book is a fascinating and informative read for all individuals working in or interested in deep space telecommunications.

Download or read book Frequency Selective Surfaces based High Performance Microstrip Antenna written by Shiv Narayan and published by Springer. This book was released on 2015-09-24 with total page 62 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book focuses on performance enhancement of printed antennas using frequency selective surfaces (FSS) technology. The growing demand of stealth technology in strategic areas requires high-performance low-RCS (radar cross section) antennas. Such requirements may be accomplished by incorporating FSS into the antenna structure either in its ground plane or as the superstrate, due to the filter characteristics of FSS structure. In view of this, a novel approach based on FSS technology is presented in this book to enhance the performance of printed antennas including out-of-band structural RCS reduction. In this endeavor, the EM design of microstrip patch antennas (MPA) loaded with FSS-based (i) high impedance surface (HIS) ground plane, and (ii) the superstrates are discussed in detail. The EM analysis of proposed FSS-based antenna structures have been carried out using transmission line analogy, in combination with the reciprocity theorem. Further, various types of novel FSS structures are considered in designing the HIS ground plane and superstrate for enhancing the MPA bandwidth and directivity. The EM design and performance analyses of FSS-based antennas are explained here with the appropriate expressions and illustrations.