Phased Array Antenna Sidelobe Reduction via Phase Offset
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Solution Overview
Problem
Phased array antennas face performance limitations due to undesirable sidelobes caused by phase quantization errors, which are exacerbated by the need for cost-effective phase shifter designs with fewer states.
Innovation Solution
A method and system that modify radiofrequency signals by adding a phase offset and bias to signal portions, ensuring the average bias is the inverse of the phase offset, to reduce sidelobes in phased array antennas, utilizing a beamsteering controller and element level phase shifters to steer the antenna beam with reduced sidelobes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the number of phase states in phase shifters is reduced to lower cost and complexity, then device complexity and cost are reduced, but sidelobe levels increase due to phase quantization errors
Solution Approach 1:
The signal is divided into multiple signal portions, each processed by separate element level phase shifters with different bias phases. This segmentation allows the system to use simpler phase shifters while maintaining overall beamforming accuracy through coordinated processing of multiple signal portions.
Solution Approach 2:
Different bias phases are applied to different signal portions corresponding to different radiating elements or element groups. This local differentiation in phase biasing compensates for quantization errors in a distributed manner, reducing sidelobes without requiring high-precision phase shifters across the entire array.
2Device complexity
If fewer T/R modules are used to reduce cost, then device complexity and cost are reduced, but phase control precision may be compromised
Solution Approach 1:
The phased array is divided into multiple groups of radiating elements, with each group processed by a separate T/R module. Element level phase shifters are then used to provide fine-grained phase control within each group, compensating for the reduced number of T/R modules while maintaining overall phase control precision.
Solution Approach 2:
Element level phase shifters act as intermediary devices between the reduced number of T/R modules and the individual radiating elements. These intermediaries provide the necessary phase control precision that would otherwise require a T/R module at each element, enabling cost reduction without sacrificing performance.
Data Source
AI summary
The Active Electronically Scanned Lens Array design for a phased array reduces the cost of the phased array with minimal sacrifice to array performance. The design replaces transmit/receive (T/R) modules at the front end of the array with low cost and low lost phase shifters. A tradeoff in this design is a periodic phase quantization error that leads to quantization lobes. To reduce quantization lobes, a phase addition approach is presented to break up with the periodicity. In the presented approach, a phase offset is added at a T/R module and then corrected for at each radiating element in the array. The applied phase offset can be either deterministic or random.