100 



BELL SYSTEM TECHNICAL JOURNAL 



The total length of this array is {n — 1) - = 2m - = 9X. All elements 



except the three central ones are separated by one wavelength since the odd 

 powers of z except z^ are missing. 



End-On Arrays with Equispaced Null Points 



We now pass to a more detailed analysis of end-on arrays with null points 

 equispaced on a given circular arc. 



t=\ 



z = 



z=t 



For an end-on array § = ^t and 



3 = gi-^^ ^ = j8/'(c0S e - 1). 



(36) 



The range of z begins at z = 1 and extends clockwise to a point determined 

 by '/' = —2^t. Let n — 1 null points be equispaced on an arc of length ^ 

 as shown in Fig. 20; the field strength is then 



V$ = 1(2 - 0(2 - t')---(z - r')\, 





(37) 



This can be expressed as 



V5 = 2-|si„i(^, + „4,) 



(38) 



