Element pattern approach to design of dielectric windows for conformal phased arrays

Modal analysis is presented for the realized element gain and plane patterns for two-dimensional cylindrical arrays with a concentric dielectric sleeve. Numerical results indicate that a dielectric window in the near field of a conformal phased array may cause significant deterioration of the element pattern due to guided wave effects. If the window is inappropriately configured, this deterioration manifests itself in appearance of pronounced dips and of an excessive off-broadside ripple. A design method of dielectric windows for conformal arrays to reduce the guided wave effects is proposed. The method is validated by direct evaluation of the and plane element patterns for optimized window geometries.