Antenna Arrays with Closely Spaced Elements

A number of arrays called "flat-top beam" antennas using closely spaced out-of-phase elements are described. Gain equations are developed for arrays with closely spaced horizontal elements above perfectly conducting ground. Curves showing the effect of spacing and loss resistance on the gain and resistance of a "flat-top beam" are presented. It is shown that at small spacings, loss resistance has an important effect on the radiating efficiency of the array. Curves illustrating the effect of height above ground on the gain and vertical radiation pattern are also given.