Element Failure Correction for a Large Monopulse Phased Array Antenna With Active Amplitude Weighting

Recently a new method is introduced to synthesize low sidelobe patterns for planar array antennas with a periodic element arrangement. The method makes use of the property that for a planar array with periodic spacing of the elements, an inverse Fourier transform relationship exists between the array factor and the element excitations. This property is used in an iterative way to derive the array element excitations from the prescribed array factor. The same method is also able to partially compensate the degradation of the sidelobe and gain performance of array patterns due to element failures. Numerical examples of array-failure correction using this method are given for ultralow sidelobe sum and difference patterns of a 5800-element circular array where the failed elements are randomly dispersed across the aperture. The tapers in this array are created exclusively by active weighting in the transmit/receive (T/R) modules using variable gain control.