دانلود کتاب طراحی و اندازه گیری آنتن ها و انتشار در سیستم های تلفن همراه

This chapter describes the basic theory of antennas to facilitate a discussion on their performance with respect to mobile base stations and terminals. For readers who are unfamiliar with the field of antenna engineering, explanations of the technical terms associated with mobile communication systems are provided. Additionally, a basic knowledge of electromagnetics is useful. Antennas are basic elements for converting radio frequency (RF) energy into electromagnetic waves that propagate through space. Their fundamental characteristics are described by an infinitesimal current element as an initial point source, and the radiation performances of differently shaped antenna elements evaluated with respect to this infinitesimal current element are explained using several supporting examples. The second part of this chapter describes the basics of mutual coupling and array antennas, which are used by mobile base stations to produce the desired radiation pattern for controlling field distributions inside the coverage area.