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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.
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.
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 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.
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 antennas Multi-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.
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 antennas Multi-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.
Till the very end of the twentieth century tsunami waves (or 'waves in a harbour', translated from Japanese) were considered an extremely rare and exotic natural p- nomenon, originating in the ocean and unexpectedly falling upon the seaside as gigantic waves. The 26th of December 2004, when tsunami waves wiped out, in a single day, more than 250,000 human lives, mourned in many countries, turned out to be a tragic date for all mankind. The authors of this book, who have studied tsunami waves for many years, - tended it to be a systematic exposition of modern ideas concerning * The mechanisms of tsunami wave generation * The peculiarities of tsunami wave propagation in the open ocean and of how waves run-up beaches * Methods for tsunami wave registration and the operation of a tsunami warning system * The mechanisms of other catastrophic processes in the ocean related to the se- mic activity of our planet The authors considered their main goal to be the creation of book prese- ing modern knowledge of tsunami waves and of other catastrophes in the ocean to scienti?c researchers and specialists in geophysics, oceanography, seismology, hydroacoustics, geology, geomorphology, civil and seaside engineering, postgr- uate students and students of relevant professions.
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