The physical limitations of omnidirectional antennas are considered. With the use of the spherical wave functions to describe the field, the directivity gain G and the Q of an unspecified antenna are calculated under idealized conditions. To obtain the optimum performance, three criteria are used: (1) maximum gain for a given complexity of the antenna structure, (2) minimum Q, (3) maximum ratio of G/Q. It is found that an antenna of which the maximum dimension is 2a has the potentiality of a broad bandwidth provided that the gain is equal to or less than 4a/. To obtain a gain higher than this value, the Q of the antenna increases at an astronomical rate. The antenna which has potentially the broadest bandwidth of all omnidirectional antennas is one which has a radiation pattern corresponding to that of an infinitesimally small dipole. PHYSICAL LIMITATIONS OF OMNIDIRECTIONAL ANTENNAS

No abstract

Dear readers, when you are hunting the new book collection to read this day, electromagnetic energy transmission and radiation can be your referred book. Yeah, even many books are offered, this book can steal the reader heart so much. The content and theme of this book really will touch your heart. You can find more and more experience and knowledge how the life is undergone. We present here because it will be so easy for you to access the internet service. As in this new era, much technology is sophistically offered by connecting to the internet. No any problems to face, just for this day, you can really keep in mind that the book is the best book for you. We offer the best here to read. After deciding how your feeling will be, you can enjoy to visit the link and get the book.

This book develops a consistent macroscopic theory of electromagnetism and discusses the relation between circuit theory and filed theory. The theory is developed in successive steps from the Lorentz force, the integral form of Maxwell's equations in free space, and suitable macroscopic models of polarized and magnetized matter. It covers the electromagnetism of moving bodies and the process of electromechanical energy conversion; introduces a power-series technique for analyzing quasi-static fields and quasi-stationary systems; it emphasizes the synthesis of fields as opposed to the analysis of fields. Presented in an appendix, the reader will also find, the four-dimensional relativistic formulation of macroscopic electrodynamics.

A theoretical study of the transmission of electromagnetic waves in hollow conducting pipes of elliptic cross section, including field configurations, critical frequencies, velocities of propagation, and attenuations for the six lowest order waves. The pipe of circular cross section is treated as a special case, and the stability of waves in it for small deformation of the cross section is discussed.