Antenna Systems

This book offers an up-to-date and comprehensive review of modern antenna systems and their applications in the fields of contemporary wireless systems. It constitutes a useful resource of new material, including stochastic versus ray tracing wireless channel modeling for 5G and V2X applications and implantable devices. Chapters discuss modern metalens antennas in microwaves, terahertz, and optical domain. Moreover, the book presents new material on antenna arrays for 5G massive MIMO beamforming. Finally, it discusses new methods, devices, and technologies to enhance the performance of antenna systems

Optimization and Communication in UAV Networks

UAVs are becoming a reality and attract increasing attention. They can be remotely controlled or completely autonomous and be used alone or as a fleet and in a large set of applications. They are constrained by hardware since they cannot be too heavy and rely on batteries. Their use still raises a large set of exciting new challenges in terms of trajectory optimization and positioning when they are used alone or in cooperation, and communication when they evolve in swarm, to name but a few examples. This book presents some new original contributions regarding UAV or UAV swarm optimization and communication aspects

Abstracts on Radio Direction Finding (1899 - 1995)

The files on this record represent the various databases that originally composed the CD-ROM issue of "Abstracts on Radio Direction Finding" database, which is now part of the Dudley Knox Library's Abstracts and Selected Full Text Documents on Radio Direction Finding (1899 - 1995) Collection. (See Calhoun record https://calhoun.nps.edu/handle/10945/57364 for further information on this collection and the bibliography). Due to issues of technological obsolescence preventing current and future audiences from accessing the bibliography, DKL exported and converted into the three files on this record the various databases contained in the CD-ROM. The contents of these files are: 1) RDFA_CompleteBibliography_xls.zip [RDFA_CompleteBibliography.xls: Metadata for the complete bibliography, in Excel 97-2003 Workbook format; RDFA_Glossary.xls: Glossary of terms, in Excel 97-2003 Workbookformat; RDFA_Biographies.xls: Biographies of leading figures, in Excel 97-2003 Workbook format]; 2) RDFA_CompleteBibliography_csv.zip [RDFA_CompleteBibliography.TXT: Metadata for the complete bibliography, in CSV format; RDFA_Glossary.TXT: Glossary of terms, in CSV format; RDFA_Biographies.TXT: Biographies of leading figures, in CSV format]; 3) RDFA_CompleteBibliography.pdf: A human readable display of the bibliographic data, as a means of double-checking any possible deviations due to conversion

Antenna Designs for 5G/IoT and Space Applications

This book is intended to shed some light on recent advances in antenna design for these new emerging applications and identify further research areas in this exciting field of communications technologies. Considering the specificity of the operational environment, e.g., huge distance, moving support (satellite), huge temperature drift, small dimension with respect to the distance, etc, antennas, are the fundamental device allowing to maintain a constant interoperability between ground station and satellite, or different satellites. High gain, stable (in temperature, and time) performances, long lifecycle are some of the requirements that necessitates special attention with respect to standard designs. The chapters of this book discuss various aspects of the above-mentioned list presenting the view of the authors. Some of the contributors are working strictly in the field (space), so they have a very targeted view on the subjects, while others with a more academic background, proposes futuristic solutions. We hope that interested reader, will find a fertile source of information, that combined with their interest/background will allow efficiently exploiting the combination of these two perspectives

Advanced Radio Frequency Antennas for Modern Communication and Medical Systems

The main objective of this book is to present novel radio frequency (RF) antennas for 5G, IOT, and medical applications. The book is divided into four sections that present the main topics of radio frequency antennas. The rapid growth in development of cellular wireless communication systems over the last twenty years has resulted in most of world population owning smartphones, smart watches, I-pads, and other RF communication devices. Efficient compact wideband antennas are crucial in RF communication devices. This book presents information on planar antennas, cavity antennas, Vivaldi antennas, phased arrays, MIMO antennas, beamforming phased array reconfigurable Pabry-Perot cavity antennas, and time modulated linear array

Aeronautical engineering: A continuing bibliography with indexes (supplement 253)

This bibliography lists 637 reports, articles, and other documents introduced into the NASA scientific and technical information system in May, 1990. Subject coverage includes: design, construction and testing of aircraft and aircraft engines; aircraft components, equipment and systems; ground support systems; and theoretical and applied aspects of aerodynamics and general fluid dynamics

Underwater & out of sight: towards ubiquity in underwater robotics

Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 2019.The Earth's oceans holds a wealth of information currently hidden from us. Effective measurement of its properties could provide a better understanding of our changing climate and insights into the creatures that inhabit its waters. Autonomous underwater vehicles (AUVs) hold the promise of penetrating the ocean environment and uncovering its mysteries; and progress in underwater robotics research over the past three decades has resulted in vehicles that can navigate reliably and operate consistently, providing oceanographers with an additional tool for studying the ocean. Unfortunately, the high cost of these vehicles has stifled the democratization of this technology. We believe that this is a consequence of two factors. Firstly, reliable navigation on conventional AUVs has been achieved through the use of a sophisticated sensor system, namely the Doppler velocity log (DVL)-aided inertial navigation system (INS), which drives up vehicle cost, power use and size. Secondly, deployment of these vehicles is expensive and unwieldy due to their complexity, size and cost, resulting in the need for specialized personnel for vehicle operation and maintenance. The recent development of simpler, low-cost, miniature underwater robots provides a solution that mitigates both these factors; however, removing the expensive DVL-aided INS means that they perform poorly in terms of navigation accuracy. We address this by introducing a novel acoustic system that enables AUV self-localization without requiring a DVL-aided INS or on-board active acoustic transmitters. We term this approach Passive Inverted Ultra-Short Baseline (piUSBL) positioning. The system uses a single acoustic beacon and a time-synchronized, vehicle-mounted, passive receiver array to localize the vehicle relative to this beacon. Our approach has two unique advantages: first, a single beacon lowers cost and enables easy deployment; second, a passive receiver allows the vehicle to be low-power, low-cost and small, and enables multi-vehicle scalability. Providing this new generation of small and inexpensive vehicles with accurate navigation can potentially lower the cost of entry into underwater robotics research and further its widespread use for ocean science. We hope that these contributions in low-cost underwater navigation will enable the ubiquitous and coordinated use of robots to explore and understand the underwater domain.This research was funded and supported by a number of sponsors; we gratefully acknowledge them below. Defense Advanced Research Projects Agency (DARPA) and SSC Pacific via Applied Physical Sciences Corp. (APS) under contract number N66001-11-C-4115. SSC Pacific via Applied Physical Sciences Corp. (APS) under award number N66001-14-C-4031. Air Force via Lincoln Laboratory under award number FA8721-05-C-0002. Office of Naval Research (ONR) via University of California-San Diego under award number N00014-13-1-0632. Defense Advanced Research Projects Agency (DARPA) via Applied Physical Sciences Corp. (APS) under award number HR0011-18-C-0008. Office of Naval Research (ONR) under award number N00014-17-1-2474

The direction finder based on the passive multichannel detection of the electromagnetic signal

Пасивно одређивање правца долазећег електромагнетског таласа (passive direction finding - DF) је једна од техничких дисциплина стандардно примењивана у различитим цивилним и војним областима. Типичан пример су пасивни системи за рану детекцију борбене технике која емитује електромагнетско зрачење, као што су летелице или пловила са активираним радарима. У области цивилне примене, употреба DF-а је много разноврснија и масовнија, па се такви системи рутински користе у сврху детекције покретних и стационарних извора зрачења, препознавања и отклањања интерференције у радио-везама, лоцирању неауторизованих предајника, у сигурносним и безбедносним сервисима, итд. Због широке области примене, DF системи могу бити различитих карактеристика, као што су: а) портабилност – могућност интеграције уређаја у мале преносиве системе, или мале покретне системе (беспилотна летелица, лако теренско возило, патролни чамац, и др.); б) рад у реалном времену; в) детекција зрачења на више фреквенцијских канала, итд. Да би се испунили тако специфични захтеви, потребно је системски приступити дизајну, што је главна тема докторске дисертације. Како је за аквизицију било које физичке величине потребан одговарајући сензор, аквизиција електромагнетских таласа, постиже се употребом одговарајућих антена, које су у DF техникама типично интегрисане у одговарајући антенски низ. За примену дефинисану у дисертацији, постоји више типова погодних антена. Са циљем селекције одговарајуће антене направљен је преглед најпогодније класе антена – антене хорн типа, и закључено је да је пирамидални хорн најбоље решење. Циљ метода процесирања сигнала добијених са антенског низа као сензора је одређивање правца долазећег електромагнетског сигнала. Могу да буду реализоване различитим типовима алгоритама, па се сходно томе методи међусобно и разликују. Иако постоје супер-резолуционе технике које дају најбоље резултате по питању резолуције, оне нису ефикасне и погодне за рад у портабилним системима, тако да је за дизајн одабрана једна од класичних техника амплитудског типа. Анализиране су основне технике амплитудског типа и одабрана је најпогоднија са становишта ефикасности хардверске и софтверске реализације, као и са становишта уведеног критеријума – амплитудског динамичког опсега. Одређивање правца електромагнетског сигнала из једног извора, уколико нема додатних нарушавајућих фактора, релативно је лако решив проблем. Озбиљан проблем настаје када се ради о више извора и који су при том физички блиски, па одређивања правца за сваки од њих може да буде у општем случају нерешив. Супер-резолуциони методи, судећи према литератури, могу да реше тај проблем у великом броју случајева, али по цену брзине, величине опреме, потрошње енергије, итд. Ако је потребно портабилно решење онда је тај проблем у основи нерешив. У пракси, физички блиски извори емитују зрачење на различитим фреквенцијским каналима, па је сукцесивном детекцијом по сваком каналу могуће детектовати и све такве изворе. Такав поступак је назван вишеканална детекција. Пошто се антенски низ као сензор користи на више фреквенција, његове карактеристике нису исте за сваки фреквенцијски канал. Уз то елементи антенског низа, у општем случају, немају идентичне карактеристике, без обзира на исту геометрију. Због тога је у дисертацији предложен поступак калибрације по свим антенама, и по свим фреквенцијским каналима, као и формирање одговарајуће табеле претраживања која омогућује касније брзо процесирање података. Теоретски, за дефинисану примену, сваки циркуларни антенски низ са усмереним антенама прилагођеним за дефинисани фреквенцијски опсег, могао би да послужи сврси. Међутим како је у питању портабилна примена, циљ је уклапање у задате димензије, односно минимизација габарита и потребног броја елемента антенског низа. Због тога је дефинисана оригинална процедура пројектовања пирамидалних хорн антена, која редефинише стандардни критеријум оптималности, и уводи додатне критеријуме који оптимизују саме антене по питању електричних и механичких карактеристика, као и комплетан антенски низ по питању броја употребљених елемента. Комплетан DF систем је реализован применом савремене аналогно-дигиталне методологије пројектовања електронских система, као и применом робусних софтверских решења. Сви блокови система, њихова функција и реализација детаљно су описани у дисертацији. За реализовани систем и процењену вероватноћу грешака које се генеришу током рада, израчуната је вероватноћа исправне детекције. Одређене су метролошке карактеристике реализованог DF система, мерењем карактеристика појединих склопова система и целог система у целини. Израчунате су мерне несигурности како за појединачне склопове, тако и за цео систем, чиме је дато виђење употребне вредности система.Passive radio direction finding DF is a technical discipline commonly used in many civil and military applications. Typical applications are passive early warning systems, such are aircrafts and vessels equipped with radars. In area of civil applications, DF usage is much more manifold and widespread: such systems are used for detection of moving or stationary radiation sources, in reconnaissance and cleaning interference in radio communications, localization of non-authorized transmitters, in intelligent and security systems, etc. According to widespread application area, DF systems might have different characteristic, such are: a) portability – ability of integration into small transferable or mobile systems (unmanned aircraft, light infantry vehicle, patrol boat, etc.); b) real time operation; c) different channel signals detection, etc. With an aim to be able to achieve all specific DF features, it is mandatory to perform a systematic design, what is the main topic of this doctoral dissertation. For the acquisition of any physical signal, appropriate sensor is required. For the case of acquisition of the electromagnetic waves in DF techniques, the sensor is based on convenient antenna, typically organized in corresponding antenna array. For the application given in the dissertation, there are several suitable types of antennas. In order to select appropriate antenna, an overview of all suitable antennas types – horn antennas, are given, and the conclusion is that the most suitable selection is the pyramidal horn antenna. The purpose of processing signals obtained from the antenna array as a sensor, is to determine the direction of the incoming electromagnetic signal. The processing can be achieved by several techniques, and accordingly, each differ one to another. Although, there are super-resolution techniques that provides the best results in terms of resolution, they are not efficient and suitable for portable systems applications, thus, the classical techniques with amplitude detection are selected for consideration. Basic amplitude detection techniques are analysed, and one is selected as the most suitable from the point of the software and hardware efficiency and implementation, same as from the point of the introduced criterion - amplitude dynamic range. Determination of an electromagnetic wave Direction, from unique radiation source, with no interfering conditions, is a quite easy task. The problem arises when it comes to presence of multiple, physically very close, radiation sources, so in general, determination of direction, per each of them, might be unsolvable. Super-resolution methods, according to literature, are able to solve such tasks in most of cases, for the price of speed, equipment size, energy consumption, etc. If a portable solution is requested, then this problem is essentially unsolvable. In practice, physically close sources radiate at different frequency channels, so by successive detection on each channel it is possible to detect all possible sources. Such a procedure is called multichannel detection. Since the antenna array, considered as a sensor, is used on multiple frequencies, its characteristics are not the same for each frequency channel. In addition, the elements of an antenna array do not have identical characteristics in general, regardless of the same geometry. Therefore, in the dissertation, a calibration procedure is proposed for all antennas, and at all frequency channels. Accordingly, constitution of lookup table that allows, efficient data processing is proposed. Theoretically, for a defined application, any circular antenna array with directional antennas adapted for the defined frequency range can be applied. However, the portable application is concerned, so the goal is to fit it into the given dimension, that is, minimize dimension and number of antenna array elements. For this reason, an original pyramidal horn antenna design procedure is defined, which redefines the standard optimization criterion, and introduces additional criteria for antenna optimization, in terms of electrical and mechanical characteristics, as well as the antenna array optimization in term of number of elements. The complete DF system was realized using the modern mix-signal electronic systems design methodology, and by applying the robust software solutions. Detail description of all system blocks, their function and realization is given in the dissertation. Using the estimated probability of errors generated during operation, the probability of correct detection is calculated. For the case of designed system, and the estimated probability of errors, the probability of correct detection is evaluated. The metrology characteristics of the realized DF system are determined, by measuring the characteristics of individual system components and the entire system itself. Measurement uncertainty for individual components and entre system are calculated, demonstrating the system quality value