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1000 tulosta hakusanalla Boris Levin

Antennas

Antennas

Boris Levin

CRC Press
2021
sidottu
The book comprises a new method of solving the integral equation of Leontovich, the most rigorous and most effective equation for the current in thin linear antennas. The book describes the features of the new method in its application in various types of antennas. It considers new ways of analyzing antennas, in particular in the calculation of an antenna gain based on main radiation patterns and the calculation of the directional characteristics of radiators with known distribution of current amplitude. The method of electrostatic analogy proposed by the author, provides the base for comparison of electromagnetic fields of high-frequency currents and electrostatic charges located on linear conductors to improve the directional characteristics of log-periodic and director-type antennas. A new approach to the analysis of the electrical characteristics of a microstrip antenna, which allows expansion of its operation range, is substantiated and developed. New results of antenna synthesis are obtained. The second part of the book is devoted to specific types of antennas (the author had a significant role in their creation). Particular attention is given to ship antennas for different frequency ranges.The book is intended for professionals, working in electrodynamics and those working on development, placement and exploitation of antennas. It will be useful for lecturers (university-level professors), teachers, students of radio engineering and researchers working in various fields of radio electronics and interested in an in-depth study of theoretical problems and designs f antennas. It can also be used for short university courses.
Antennas

Antennas

Boris Levin

TAYLOR FRANCIS LTD
2023
nidottu
The book comprises a new method of solving the integral equation of Leontovich, the most rigorous and most effective equation for the current in thin linear antennas. The book describes the features of the new method in its application in various types of antennas. It considers new ways of analyzing antennas, in particular in the calculation of an antenna gain based on main radiation patterns and the calculation of the directional characteristics of radiators with known distribution of current amplitude. The method of electrostatic analogy proposed by the author, provides the base for comparison of electromagnetic fields of high-frequency currents and electrostatic charges located on linear conductors to improve the directional characteristics of log-periodic and director-type antennas. A new approach to the analysis of the electrical characteristics of a microstrip antenna, which allows expansion of its operation range, is substantiated and developed. New results of antenna synthesis are obtained. The second part of the book is devoted to specific types of antennas (the author had a significant role in their creation). Particular attention is given to ship antennas for different frequency ranges.The book is intended for professionals, working in electrodynamics and those working on development, placement and exploitation of antennas. It will be useful for lecturers (university-level professors), teachers, students of radio engineering and researchers working in various fields of radio electronics and interested in an in-depth study of theoretical problems and designs f antennas. It can also be used for short university courses.
Wide-Range Antennas

Wide-Range Antennas

Boris Levin

CRC Press
2021
nidottu
Expanding the range of antenna frequency is the main objective of this book. Solutions proposed are based on the development of new theoretical methods for analyzing and synthesizing antennas. The book shows that concentrated capacitive loads connected along linear and V-antennas provide a high level of matching with a cable over a wide frequency range and improves directional characteristics of antennas, i.e. increases the communication distance.New theoretical methods are proposed for analysis and synthesis of antennas under consideration: 1) method of calculating directional characteristics of radiators with a given current distribution, and 2) method of electrostatic analogy for calculating mutual and total fields of complex multi-element radiating structures. These methods allow us to obtain optimal directional characteristics for director-type antennas (arrays of Yagi-Uda) and log-periodic antennas with concentrated capacitances and show that use of capacitors makes it possible to extend the frequency range of the director antennas and to decrease dimensions of the log-periodic antennasMulti-element (flat and three-dimensional) self-complementary antennas with different variants of connecting generator poles and cable wires to antenna elements are proposed, which improves the matching with a cable. Characteristics of flat structures are compared with characteristics of volume structures: conical, parabolic, and located on a pyramid edges.The book describes new versions of transparent antennas, antennas for cellular communication, multi-tier and multi-radiator antennas, and much more.
Antenna Engineering

Antenna Engineering

Boris Levin

CRC Press
2021
nidottu
The book deals with theoretical and experimental research of antennas. The presentation is based on the electromagnetic theory. It begins with the theory of thin antennas. Thin antennas represent one of the main types of radiators, thus the theory of thin antennas is the basis of the antennas analysis. Special attention is paid to the integral equation of Leontovich-Levin for a current along a straight thin-walled metal cylinder, which is equivalent to the equation of Hallen with a precise kernel. Together with the analysis of various types of antennas, the book deals with the problems of synthesis including the creation a wide-band radiator by means of determining of the types and the magnitudes of concentrated loads, which are connected along a linear radiator and create in a given frequency band high electrical performance. Problems of antenna engineering are discussed in the second half of the book, including the results of application of a compensation method for the protection of humans against irradiation and structural features of ship antennas.
Antennas

Antennas

Boris Levin

TAYLOR FRANCIS LTD
2024
sidottu
This book describes both known and new results. In the sections devoted to the use of integral equations for the current in a linear metal radiator, the focus is on Leontovich's equation. An advantage of this equation is the simplicity of the solution and the absence of the argument f in it because the integration over f already performed. The refined solution makes it possible to determine the total sum of the series for the current, which is close to the known solution including only the first terms. The results of the synthesis of different types of antennas with capacitive loads are presented, which makes it possible to implement Hallen's hypothesis about the usefulness of applying such loads to create an in-phase current distribution in antennas and to obtain required characteristics.New results include the widespread use of the complex potential method in relation to the calculation of capacitive structures in homogeneous and inhomogeneous media, antenna patterns and flows of electrical fields between antenna elements and in the surrounding space. In particular, the analysis of field flows makes it possible to substantiate a rigorous method for analyzing microstrip antennas. The characteristics of antennas in various conditions of their installation are considered and compared. The results of the use of multi-floors structures that provide in the wide frequency range the radiation in direction perpendicular to the antenna axis, and structures that make it possible to reduce the mutual influence of antennas located at different heights on a common mast are described.
Wide-Range Antennas

Wide-Range Antennas

Boris Levin

CRC Press
2019
sidottu
Expanding the range of antenna frequency is the main objective of this book. Solutions proposed are based on the development of new theoretical methods for analyzing and synthesizing antennas. The book shows that concentrated capacitive loads connected along linear and V-antennas provide a high level of matching with a cable over a wide frequency range and improves directional characteristics of antennas, i.e. increases the communication distance.New theoretical methods are proposed for analysis and synthesis of antennas under consideration: 1) method of calculating directional characteristics of radiators with a given current distribution, and 2) method of electrostatic analogy for calculating mutual and total fields of complex multi-element radiating structures. These methods allow us to obtain optimal directional characteristics for director-type antennas (arrays of Yagi-Uda) and log-periodic antennas with concentrated capacitances and show that use of capacitors makes it possible to extend the frequency range of the director antennas and to decrease dimensions of the log-periodic antennasMulti-element (flat and three-dimensional) self-complementary antennas with different variants of connecting generator poles and cable wires to antenna elements are proposed, which improves the matching with a cable. Characteristics of flat structures are compared with characteristics of volume structures: conical, parabolic, and located on a pyramid edges.The book describes new versions of transparent antennas, antennas for cellular communication, multi-tier and multi-radiator antennas, and much more.
Antenna Engineering

Antenna Engineering

Boris Levin

Productivity Press
2016
sidottu
The book deals with theoretical and experimental research of antennas. The presentation is based on the electromagnetic theory. It begins with the theory of thin antennas. Thin antennas represent one of the main types of radiators, thus the theory of thin antennas is the basis of the antennas analysis. Special attention is paid to the integral equation of Leontovich-Levin for a current along a straight thin-walled metal cylinder, which is equivalent to the equation of Hallen with a precise kernel. Together with the analysis of various types of antennas, the book deals with the problems of synthesis including the creation a wide-band radiator by means of determining of the types and the magnitudes of concentrated loads, which are connected along a linear radiator and create in a given frequency band high electrical performance. Problems of antenna engineering are discussed in the second half of the book, including the results of application of a compensation method for the protection of humans against irradiation and structural features of ship antennas.
The Theory of Thin Antennas and Its Use in Antenna Engineering
This book deals with the methods of theoretical and experimental research of antennas, which are based on the electromagnetic (EM) theory. The theory of thin antennas is the basis of antenna analysis, as thin antennas represent one of the main types of radiators and are extensively applied as both independent antennas and as elements of more complicated antennas. The contents of the book cover new methods of antenna analysis and design, including the theory of electrically coupled lines, the methods of complex potential, compensation, impedance line, and mathematical programming among others. New results of using these methods are obtained and described. The complex potential method is generalized to inhomogeneous media and is employed in conical and parabolic problems. The theory of electrically coupled lines allows considering theoretical problems of multi-conductor cables and multi-radiator antennas. The compensation method permits creating a weak field area in the near region of a transmitting antenna. The method of impedance line is applied to antennas with loads, and it permits, together with the method of mathematical programming, selecting loads to develop antennas with the required characteristics. The methods described within this text enable engineers to calculate parameters for new types of antennas, particularly, of new self-complementary antennas. In the general case, its properties pertain to the three-dimensional self-complementary antennas, their variants are considered in the book. Close attention is also paid to the field compensation in the near region of a transmitting antenna and to the creation of the 'dark spot'. The book is an essential reference for graduates and researchers requiring knowledge of the design and engineering of new antennas as well as the underlying electromagnetic and mathematical methods of its analysis and synthesis.
Physics of Tsunamis

Physics of Tsunamis

Boris W. Levin; Mikhail Nosov

Springer International Publishing AG
2015
sidottu
This second edition reflects significant progress in tsunami research, monitoring and mitigation within the last decade. Primarily meant to summarize the state-of-the-art knowledge on physics of tsunamis, it describes up-to-date models of tsunamis generated by a submarine earthquake, landslide, volcanic eruption, meteorite impact, and moving atmospheric pressure inhomogeneities. Models of tsunami propagation and run-up are also discussed. The book investigates methods of tsunami monitoring including coastal mareographs, deep-water pressure gauges, GPS buoys, satellite altimetry, the study of ionospheric disturbances caused by tsunamis and the study of paleotsunamis. Non-linear phenomena in tsunami source and manifestations of water compressibility are discussed in the context of their contribution to the wave amplitude and energy. The practical method of calculating the initial elevation on a water surface at a seismotectonic tsunami source is expounded. Potential and eddy traces ofa tsunamigenic earthquake in the ocean are examined in terms of their applicability to tsunami warning. The first edition of this book was published in 2009. Since then, a few catastrophic events occurred, including the 2011 Tohoku tsunami, which is well known all over the world. The book is intended for researchers, students and specialists in oceanography, geophysics, seismology, hydro-acoustics, geology, and geomorphology, including the engineering and insurance industries.
Physics of Tsunamis

Physics of Tsunamis

Boris W. Levin; Mikhail Nosov

Springer International Publishing AG
2016
nidottu
This second edition reflects significant progress in tsunami research, monitoring and mitigation within the last decade. Primarily meant to summarize the state-of-the-art knowledge on physics of tsunamis, it describes up-to-date models of tsunamis generated by a submarine earthquake, landslide, volcanic eruption, meteorite impact, and moving atmospheric pressure inhomogeneities. Models of tsunami propagation and run-up are also discussed. The book investigates methods of tsunami monitoring including coastal mareographs, deep-water pressure gauges, GPS buoys, satellite altimetry, the study of ionospheric disturbances caused by tsunamis and the study of paleotsunamis. Non-linear phenomena in tsunami source and manifestations of water compressibility are discussed in the context of their contribution to the wave amplitude and energy. The practical method of calculating the initial elevation on a water surface at a seismotectonic tsunami source is expounded. Potential and eddy traces ofa tsunamigenic earthquake in the ocean are examined in terms of their applicability to tsunami warning. The first edition of this book was published in 2009. Since then, a few catastrophic events occurred, including the 2011 Tohoku tsunami, which is well known all over the world. The book is intended for researchers, students and specialists in oceanography, geophysics, seismology, hydro-acoustics, geology, and geomorphology, including the engineering and insurance industries.
Boris

Boris

Cynthia Rylant

Harcourt Children's Books
2006
nidottu
Boris is a big gray cat who loves sleeping and playing and exploring and hunting. And his owner loves him for all of his simple cat ways. But Boris, typical as he may be, is part of a much larger story in this moving exploration of love, longing, compassion, and most of all, the continuous give-and-take of true friendship. Newbery medallist Cynthia Rylant's powerful collection of poems will resonate in the hearts of readers of all ages.
Boris

Boris

Andrew Gimson

Simon Schuster Ltd
2016
nidottu
THE MAKING OF A PRIME MINISTER 'My biography of the year' Michael Crick 'The scariest thing I've read since Silence of the Lambs' Ken Livingstone A brilliant and definitive biography of Boris Johnson, the politician who risked his career to lead the Brexit campaign, won the referendum, and finally became the new prime minister. In Andrew Gimson's acclaimed biography of the most colourful British politician of modern times, we are given a comprehensive portrait of the man. Despite tabloid controversies which led to him being dismissed from Michael Howard's shadow cabinet, Boris bounced back to win two terms as London mayor. It was a remarkable tribute to his huge personal popularity, and he was at the heart of things when London showcased itself during the 2012 Olympics. This updated edition of the book is a comprehensive insight into the dramatic political events of 2016. After Boris decided to join the Brexit campaign, which he led with Michael Gove, against all the predictions he secured a historic vote to leave the EU. Within a few tumultuous and unprecedented days, David Cameron resigned as prime minister, Boris was installed as favourite to succeed him - only for Gove to torpedo his challenge, and seemingly end his career. Yet when Theresa May took charge, she surprised many by appointing Boris as Foreign Secretary. Gimson's superb account not only takes the reader behind the scenes, it vividly brings to life one of the most extraordinary political careers in our history.
Boris

Boris

E J Chambers

Createspace Independent Publishing Platform
2015
pokkari
Do you believe in dragons? Sybil does and it gets her into all sorts of bother until, one day, a small, pink fluffy one appears on the end of her bed. With Boris in tow, Sybil tackles everyday school problems such as mean teachers, class bullies and wandering pencils.
Boris

Boris

Allan Winneker

Authorhouse
2021
sidottu
This is the tale of a charming, intelligent adult with non-existent scruples, who delivers results for his employer that often yield catastrophic endings for those brought into his sphere of influence.
Boris

Boris

Allan Winneker

Authorhouse
2021
pokkari
This is the tale of a charming, intelligent adult with non-existent scruples, who delivers results for his employer that often yield catastrophic endings for those brought into his sphere of influence.