The problems and techniques of linear-array design have been divided in this chapter into three general parts. The first concerns itself with general pattern theory, that is, the relation between the far-zone pattern of an array and the amplitude and phase distribution among the elements and their spacing; in this section no attention is paid to the problem of realizing a given amplitude and phase distribution. The second part is a survey of the radiating elements that have been developed for micro wave arrays. The final division treats the problems associated with combination of the elements into linear arrays and the techniques avail able to produce the desired amplitude and phase distributions.