Directivity of Uniformly Spaced Optimum Endfire Arrays With Equal Sidelobes

A mathe matical formulation is devised for a uniformly spaced and uniformly progressively phased antenna array of a given number of isotropic ele ments such that the final radiation pattern is end fire with no large bac klobe. The pallern also has the maximum number of sidelobes of equal level, modifying the result of an earlier paper, eve n when the ele ment spacing is made arbitrarily small. The directive gain , the fir st null beamwidth , the half·power beamwidth, the current excitations, and the required phases for s uch an array are given in c urves as a fun ction of the ele me nt spacin g. It is shown that the li miting radiation characteri s ti cs whe n the ele ment spacing approaches zero can also be de termined in a relatively simple manne r.