A Study of the Effect of Element Spacing on Performance of Linear Arrays.

摘要

It is well known that the beamwidth of the main lobe of the directivity pattern of a linear array with elements spaced at half wavelengths may be narrowed by lengthening the array,and increasing the number of elements in proportion. The beamwidth can also be decreased by placing more elements in the given array length,thus spacing them closer than a half-wavelengths,and at the same time applying shading factors,including phase reversals,to the elements. On the other hand,the array length can be shortened by spacing the elements more closely,without increasing the beamwidth more than a prescribed amount. Of course,shading factors must be applied. Closer spacing of the elements,together with shading,affects the directivity pattern,beamwidth,signal gain,noise gain,signal-to-noise gain,and the directivity index,in various ways. The principal purpose of this study is to determine the degree of degradation of the array performance which results from a reduction of beamwidth or array length. The unshaded array with elements at half wavelength spacing is used as the reference. (Author)