PLANE PHASED ARRAYS: DEPENDENCE OF GAIN ON STEERING, THINNING AND ELEMENT DIRECTIVITY.

摘要

Two related topics in the design of plane phased arrays are discussed. One is the dependence of gain upon thinning,steering and element directivity; the other is a systematic procedure for locating the elements of highly thinned,plane arrays. A few general observations on the effects of thinning and steering can be made from the expression for the gain of an array of elements having an arbitrary directivity factor. The specializations to isotropic elements and to infinitesimal dipoles are then made and these observations are verified for some actual arrays. A systematic way to randomize element locations in a thinned array while still approximating some basic excitation taper is also suggested and illustrated. The thinning scheme is based on an equal area approximation to a continuous excitation distribution,with the equal areas being laid out in the form of an expanding spiral. This procedure insures against accidental element alignment in any particular direction. Its effectiveness is shown by applying it to a 100-element array and plotting several sections of the resulting directivity pattern. (Author)