Phased Array Radar Super-Element Randomization for Sidelobe Reduction
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Solution Overview
Problem
Large phased array radars face issues with increased peak sidelobe levels and scan loss due to amplitude taper quantization and grating lobes, which are exacerbated by finite instantaneous bandwidth and non-uniform illumination, leading to higher costs and complexity.
Innovation Solution
Randomizing the location and length of super-elements within columns in a phased array radar system, allowing for reduced sidelobes without increasing array costs or complexity, by arranging super-elements end-to-end with randomized positions and lengths, thereby suppressing grating lobes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If super-elements are arranged in a regular lattice pattern, then the array structure is simple and easy to manufacture, but sidelobe levels increase due to grating lobes and amplitude taper quantization effects
Solution Approach 1:
The patent applies asymmetry by randomizing the positions of super-elements within columns, breaking the regular lattice pattern. This randomization creates an asymmetric distribution that suppresses grating lobes and reduces sidelobe levels while maintaining the same average density and coverage area as the regular pattern.
Solution Approach 2:
The patent changes the positional parameters of super-elements from fixed regular intervals to randomized positions within specified ranges. Each super-element's position is varied by adding random offsets to the regular grid coordinates, transforming the deterministic parameter set into a stochastic one that reduces coherent sidelobe formation.
2Object-generated harmful factors
If multiple size super-elements or subarrays are used to suppress sidelobes, then sidelobe levels are reduced, but array cost and complexity increase
Solution Approach 1:
The patent applies local quality by introducing randomness only in the super-element positions within columns, while keeping all other aspects of the array uniform. This localized modification affects only the spatial distribution parameter, leaving the super-element dimensions, feed networks, and beamforming architecture unchanged, thus avoiding system-wide complexity increases.
Solution Approach 2:
Instead of using multiple sizes of super-elements to control sidelobes (the conventional approach), the patent inverts the problem by using uniform-sized super-elements with randomized positions. This inverse approach achieves sidelobe suppression through spatial randomness rather than dimensional variation, simplifying the overall array design.
3Object-generated harmful factors
If super-element size is reduced to suppress sidelobes, then sidelobe levels are reduced, but scan loss increases and scan volume is reduced
Solution Approach 1:
The patent addresses the sidelobe problem by moving from controlling super-element dimensions (one-dimensional approach) to controlling super-element positions (spatial distribution approach). This dimensional shift from size-based control to position-based control allows sidelobe suppression without the penalty of increased scan loss associated with smaller elements.
Data Source
AI summary
Methods and apparatus for a phased array radar system including an array comprising columns of super-elements containing radiator elements located along a length of the super-element, wherein the super-elements form the columns such that super-elements are arranged end-to-end, wherein the super-elements are arranged in the column at randomized locations to reduce sidelobes. In a further embodiment, super element lengths can be randomized.