Reconfigurable Antenna Arrays with Null Limiters
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Solution Overview
Problem
Active electronically scanned antennas (AESAs) often produce null depths that are too deep for export to certain countries, necessitating a solution to adjust null depths selectively without compromising performance.
Innovation Solution
Incorporating a null limiter with dither circuits that introduce noise to phase and amplitude shifts, allowing the antenna to produce nulls with depths adjustable above or below a threshold value, enabling the same antenna to produce deep nulls for domestic or international sales by controlling the null depth through a control signal or authentication mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the antenna produces deep nulls to improve performance, then the null depth is improved, but the antenna becomes subject to export restrictions
Solution Approach 1:
The patent implements a null limiter that dynamically adjusts the null depth of the antenna based on operational conditions. The system can switch between deep null configurations (for domestic use) and shallower null configurations (for export compliance), making the antenna adaptable to different regulatory environments while maintaining optimal performance where permitted
Solution Approach 2:
The invention changes the null depth parameter of the antenna by introducing dithering signals that modify the phase and amplitude of the antenna elements. This parameter modification allows the same physical antenna to produce variable null depths, enabling it to meet different export requirements without hardware changes
2Adaptability or versatility
If dither circuits are added to adjust null depth, then the adaptability is improved, but the device complexity increases
Solution Approach 1:
The patent introduces a null limiter as an intermediary component between the beamformer and the antenna elements. This limiter incorporates dithering circuits that add controlled noise to the signal paths, effectively modifying the null depth without requiring complete redesign of the antenna system. The intermediary approach allows incremental complexity addition while achieving the desired adaptability
Solution Approach 2:
The null limiter circuit serves multiple functions: it limits the maximum null depth to comply with export regulations, it can be disabled to allow deep nulls for domestic use, and it provides a unified solution that works across different operational modes. This multi-functionality reduces the need for separate systems for different markets
Data Source
AI summary
An apparatus may include a plurality of antenna elements forming an antenna array. The apparatus may further include a beamformer that determines one or more of phase and amplitude shifts to cause the plurality of antenna elements to produce a beam in the direction of a target. The apparatus may further include a null limiter comprising dither circuits. The dither circuits may dither the one or more of phase and amplitude shifts by adding noise to cause a side lobe of the beam to increase above a threshold value. The dither circuits may be enabled by a control signal, and the dithered one or more of phase and amplitude shifts may be provided to the antenna elements to produce the beam in the direction of the target with the side lobes above the threshold value.