current distribution I e (Z q ). At a beam-pointing angle 9 , the azimuth pattern is 



given by E c (q>,9 ), and depends only on the distribution /(cc ). The elevation pat- 

 tern at 9 is 



E c (q> ,6)E e (e) (3) 



and hence depends on both / c (a p ) and l e (Z ). In the direction of the beam, how- 

 ever, the variation of E(q> ,6) with 6 is small compared with the variation of E e (9). 

 Thus, for practical purposes, the elevation pattern is completely determined by 

 the distribution l e (Z q ). This is shown in figures 50-53 which give radiation 



patterns computed using a 32-element Taylor distribution for I e (Z ) and expres- 

 sion (3). As shown by this discussion, it is clear that ring-array techniques are 

 directly applicable to azimuth-beam forming and steering and that linear-array 

 techniques are applicable for elevation-beam steering. 



For a beam at 9 , the required phases of I c (a ) and I e (Z ) are 



A c (a p ) = -^Lpcos0 o (l-cosa p ) (4) 



A e (ZJ = .?l!Ldsin0 o 



It should be noted that A c (a p ) is not essential to pointing the beam at 6 , but is 

 the phase required to give (approximately) the optimum azimuth pattern at O . 



47 



