Combining multiple sub-apertures for reduced-profile shipboard SATCOM-antenna panels

In naval SATCOM applications, there are advantages to using multiple antenna panels, each of limited scan range covering only a portion of the required hemisphere. For mechanical steering, the depth of each panel can be reduced by dividing the required aperture into smaller sub apertures at the cost of needing coherent combining. Some aspects of operating such an antenna system are considered. The EIRP, G/T and antenna patterns of combined signals are derived under the assumption of perfect coherent combining. Effects of errors in phase and in time-delay matching are provided in terms of power loss and data rate supported. Practical methods of implementing coherent combining are presented.