Dual-Band Phased Array Subarrays for Grating Lobe Mitigation
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Solution Overview
Problem
Phased array antennas face challenges in achieving wide angular scanning without grating lobes, particularly in dual-band operations, where existing methods either reduce scanning area, increase costs, or compromise radar performance.
Innovation Solution
A dual-band phased array antenna design with independently steerable planar subarrays having different boresight normal vectors, arranged on a regular or irregular polyhedral surface, ensuring radiating elements are compatible with the λ/2 condition for the lower band and suppressing grating lobes in the upper band.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the distance between radiating elements is increased to reduce the number of elements, then cost is reduced, but grating lobes appear in the radiation pattern
Solution Approach 1:
The antenna array is divided into multiple subarrays, each with its own phase shifters and beamforming capabilities. This segmentation allows independent control of each subarray's radiation pattern, enabling the system to maintain element spacing larger than λ/2 while suppressing grating lobes through coordinated subarray beamforming.
Solution Approach 2:
The patent transitions from conventional 2D planar subarray arrangements to 3D tetrahedral subarray configurations. This dimensional change provides additional spatial degrees of freedom for beamforming, enabling more effective grating lobe suppression while maintaining reduced element density.
2Object-generated harmful factors
If the distance between radiating elements is decreased to satisfy the λ/2 condition, then grating lobes are suppressed, but the number of elements and associated TRMs increases, raising cost
Solution Approach 1:
By segmenting the array into independently controllable subarrays, the patent achieves grating lobe suppression through coordinated beamforming rather than relying solely on dense element spacing. Each subarray can be optimized with larger element spacing while the collective subarray arrangement maintains overall pattern control.
Solution Approach 2:
The patent changes the geometric parameters of the subarray configuration from conventional 2D planar to 3D tetrahedral arrangements. This parameter change enables more efficient spatial utilization and grating lobe control with fewer total elements.
3Object-generated harmful factors
If the operation frequency is lowered to avoid grating lobes, then grating lobe issues are reduced, but antenna beam width increases and directivity decreases
Solution Approach 1:
The patent implements dynamic beamforming control across multiple subarrays, allowing the system to adaptively adjust beam patterns and suppress grating lobes through electronic control rather than relying on fixed geometric constraints that would limit angular resolution.
Solution Approach 2:
By changing the operational parameters of each subarray's beamforming weights and phases, the system can maintain high directivity and angular resolution while suppressing grating lobes, avoiding the need to lower the operating frequency.
4Reliability
If separate antennas are used for lower and upper bands, then each antenna can be optimized for its band, but system complexity and cost increase
Solution Approach 1:
The patent designs a universal dual-band antenna system where the same physical array structure and subarray configuration serve both lower and upper frequency bands. The multi-functional subarray architecture enables single-polarization operation across both bands without requiring separate antenna systems.
Solution Approach 2:
The patent employs periodic switching and beamforming across subarrays to handle different frequency bands, allowing the same hardware to be time-multiplexed or frequency-multiplexed for dual-band operation, reducing the need for separate dedicated antennas.
Data Source
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AI summary
Dual-Band phased array antenna with built-in grating lobe mitigation comprising: - an array of radiating elements (110) capable of working at both bands and arranged at distances small enough, avoiding grating lobes with respect to the lower band within the desired field of view, - whereas the radiating elements are arranged in planar subarrays (100) which can be steered independently from each other, and - each of the subarrays (100) has a different boresight normal vector, so that grating lobes in the upper band being mitigated.