Earth-coverage beams from geosynchronous active transmit phased arrays

Large-aperture active transmit phased arrays are effective at producing narrow beams. However to economize on weight, future architectures may also require these arrays to produce relatively wide Earth-coverage beams. This paper discusses the trades that are involved including the number of elements in the array and the element spacing, as well as the effects of phase quantization and element failure. Beam spoiling is accomplished with phase-only control of the elements, and the minimum EIRP projected onto the Earth is discussed relative to that produced by an Earth-coverage horn with a TWTA