The Multi-Lens Array Architecture

As communication and radar systems migrate toward wider bandwidths, the quantization lobes inherent in conventional phased array systems manifest as one of the foremost challenges for array designers who must consider not only the need for a large and inexpensive array with wideband requirements but also practical issues, such as the ease of transporting and realizing such an array. Large phased arrays based on conventional subarray architecture, with time delays at the subarray level, exhibit very high quantization lobes when scanned over a wide bandwidth. This paper describes a multi-lens ML array architecture that is suitable for very large arrays with wideband bandwidth to center frequency ratio greater than 0.2 scanning requirements. In addition to having low quantization lobes, the ML array architecture is modular, scalable, and compact in volume. The proposed architecture approximates the ideal gradient time delay network with a combination of time delays at the subarray level, time delays of Rotman lenses, and small phase shifts. The basic idea behind the ML architecture is to concatenate multiple modified Rotman lenses together to form a large array with non-periodic phase settings across the large array to lessen the accumulation of quantization lobes at any specific angle.