Constrained-Feed Techniques for Phased-Array Subarrays

With the increased and planned future use of very large antenna arrays for space-based radar, communication, and large, ground-based apertures, there is an urgent need to reduce the number of control components, including phase shifters, attenuators, and time-delay units, to reduce the cost and complexity of future designs. A common solution involves the implementation of a subarray architecture in which time delay and phase shift are applied to groups of elements rather than the individual array elements. Current methods using uniform contiguous subarrays have high sidelobes, and space-fed overlapped subarray structures are extremely large and heavy. This novel, constrained-feed technique uses a multiplicity of small, constrained networks, each of which produces low sidelobes, and connects these together in a modular design that can be used with analog, digital, or optical beamformers to provide high gain with very low sidelobes. The technology is appropriate for: Remote sensing of crops or sea state Airport precision approach radar Design benefits over current technology: Lower sidelobes (<30dB) Smaller, lighter structure