ABSTRACTS OF TKCFINICAL AiniCLKS 819 



eqiuitiuu expresses a relation between tlie u\-eragc electric intensity tangential 

 to a given curve and the time rate of change of the average magnetic intensity 

 normal to a surface bounded b}' this curve. The other equation expresses a com- 

 plementary relation. The reatler will l)e impressed by a simple phj-sical picture 

 from which the authors are able to deri\'e the expression for the radiation field 

 of a short antenna. In this chapter they discuss the effect of heat loss and imped- 

 ance mismatch on the elficiency of antennas. Among other topics will be found di- 

 r(M'ti\'e radiation and reception, large antenna arraj's, horns, leflectors, and lenses. 



After this extended general introduction a more detailed analysis of \'arious 

 problems begins. Chapter 2 is devoted to Maxwell's equations and Chapter 3 

 to plane waves on conductors and in free space. The main topic in Chapter 4 

 is the derivation of the expressions for the complete field surrounding a short 

 antenna from Maxwell's equations. The authors have made a si)ecial effort to 

 show the connection between this field and the oscillating charge in the antenna. 



Applications of this l>asic theory begin with (-hapter 5 devoted to directive 

 radiation. This chapter is concerned with radiation ]mtterns of vaiious arrays 

 ami with calculation of radiated i)ower. A novel method, the method of momonts 

 (pp. 162-195), is likel}' to prove valuable when spatial distrilnitions of antenna 

 current are complicated (as in the case of shunt-fed antennas). Chapter 6 ex- 

 plains methods for calculating directivites and effective areas of antennas. 

 Some ground effects are considered briefly in Chapter 7. In Chapter 8, the dis- 

 cussion of current distributions in antennas made up of tliin wires is particularly 

 thorough. First, simjjle approximations are developed; then the effects of var- 

 ious factors are carefuUj' examined. Various reciprocity and cii'cuit equivalence 

 theorems, so useful in antenna analysis, are collected in Chapter 9. 



Beginning with Chapter 10 the general theory is applied to specific antenna 

 tj'pes. Thus, small antennas are treated in Chapter 10; quarter-wave, half-wave 

 and full-wave antennas in Chapter 11; general dipole antennas in Chapters 12 

 and 13; rhombic antennas in Chapter 14; miscellaneous types of w4re antennas 

 in Chapter 15; horn antennas in Chapter 16; slot antennas in Chapter 17; re- 

 flectors in Chapter 18; and lenses m Chapter 19. 



Practical engmeers will be delighted with the appendices which contain in a 

 compact form some of the most useful information about transmission lines, 

 (.lipole antennas, antenna array's, optimum horns, and lenses. Teachers will 

 welcome the numerous problems scattered throughout the book. 



Advanced Antenna Theory. By Sergei A. Schelkunoff, 216 + xii 

 pages, John Wiley and Sons, Inc., New York (1952). Price: $6.50. 



This book is a recent addition to Wiley's Applied Mathematics Series edited 

 by I. S. Sokolnikoff. It is concerned with recent advances in antenna theory and 

 is divided into six chapters. General expressions in spherical coordinates are 

 derived for electromagnetic fields in free space and in the presence of conducting 

 cones and thin wires diverging froni a common point. In Chapter 2 these expres- 

 sions are applied to dipole antennas, vee antennas, end-fed antennas, etc. Chap- 

 ter 3 gives an account of Stratton and Chu's theory of spheroidal antennas. 

 Integral equations in antenna theory and Hallen's method of their solution are 

 tieated in Chapters 4 and 5. The book is concluded with a chapter on natural 

 oscillations in antennas. A substantial number of problems and several interest- 

 ing appendices will be found at the end. 



