A GIBBSIAN MODEL FOR FINITE SCANNED ARRAYS

A finite-by-infinite array of thin half-wave dipoles with H-plane scan is used to show the existence of a Gibbs' phenomenon-type standing wa ve in scan impedance (normalized by the infinite array value) over the elements of the array. The period of this wave is .5 lambda at broads ide for lambda/2 array spacing and increases as the scan angle increas es by a grating lobe-type expression. A simple empirical model based o n Gibbs oscillations is fitted to the scan-impedance wave; the model p redicts the 1/(1 - sin theta(0)) period variation, and should be usefu l for systems trades and for preliminary design purposes.