Phased array flatness effects on antenna system performance

Large S-Band phased array performance degradation effects are quantified under conditions of parametric array face Z-directed deformations. Phased array diameters of 7.5 and 15 feet are examined. The array face deformations can have a sag, potato chip, sinusoidal or Bessel character. The sag, potato chip, and Bessel deformations can be asymmetric with the peak deformations as far as 0.50 radii from the center of the array in any direction. Sinusoidal deformations for frequencies of 1, 2, and 3 Hz in the x-direction are examined. For all types of deformations, peak-to-peak errors from 0.1 to 0.5 inches are investigated. Beam pointing error increases with both decreasing array size and increasing deformation asymmetry. Main beam gain loss does not change with array size, but increases with increasing deformation asymmetry and decreases with increasing scan angle. Both beam pointing error and gain loss can be compensated with element level phase corrections if the deformation profile is known accurately.