Impedance-match and element-pattern constraints for finite arrays

It is shown how an
N
-element antenna array may in principle be impedance matched by means of a specially designed interconnecting feed network to
N
real generators (for arbitrary excitation of these generators). The resulting element patterns for a single excited element (a single generator) in the terminated-array environment are then calculated. It is shown that for closely spaced regular arrays a condition of partial match, as contrasted with perfect match for all excitations, is the more appropriate design objective. The theory is illustrated through application to a uniform array of line sources. Element patterns obtained with an appropriately matched finite array are compared with those from the corresponding matched infinite-array model, the latter patterns having been obtained previously by an independent technique. The range of finite-array parameters to which the infinite-array model approximately applies is discussed.