Abstract: Mutual coupling between radiative elements (210, FIG. 2) in a phased array antenna (110, FIG. 1) is employed to extend the effective aperture dimension of a radiative element. Mutual coupling is used to force selected modal resonances to occur in the radiative elements (210). The forced modal resonances create zeroes of transmission which are employed to improve the roll-off characteristics of the radiative element's radiation pattern.

Abstract: An array antenna (10) having a plurality of antenna elements (12) keeps only a subset of elements active during normal antenna operation. When a failure of one of the active elements in the array (10) is detected, one of the previously inactive elements (46) is activated to operate as a replacement for the failed element (50). The number of elements that are active during normal operation is selected to achieve a level of antenna performance required by an underlying antenna application. Thus, a desired level of antenna performance is maintained during the life of the array antenna (10) without the consumption of excess power by spare elements in the antenna. Redistributions of inactive element locations are periodically performed during the life of the array antenna (10) to enhance antenna performance in light of failed element locations.