Hierarchical Phased-Array Antenna Calibration via Subarray Segmentation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Large phased-array antennas require extensive calibration due to a vast number of possible antenna weight vectors (AWVs), making brute-force calibration impractical and time-consuming, especially when precision alignment of transmit and receive beams is necessary for efficient signal transmission and reception.
Innovation Solution
The method involves breaking down the antenna into smaller subarrays for calibration, using a serial bus to disseminate phase shift control information efficiently, and employing a hierarchical calibration process that includes mechanical adjustment and signal strength optimization to reduce the number of calibration states, allowing for quicker and more precise alignment of transmit and receive beams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If brute-force calibration is used to calibrate all possible antenna weight vectors, then alignment precision between transmit and receive beams is improved, but calibration time becomes excessively long
Solution Approach 1:
The patent divides the large phased-array antenna into multiple smaller subarrays, each with its own calibration process. Instead of calibrating all antenna elements simultaneously through brute-force methods, the system performs calibration on individual subarrays separately, significantly reducing the computational complexity and time required while maintaining alignment precision.
Solution Approach 2:
The patent implements a two-stage calibration process where a rough alignment is performed first using a limited set of antenna weight vectors, followed by a fine-tuning stage that refines the alignment. This preliminary action reduces the search space for the optimal AWV, thereby reducing overall calibration time while achieving precise alignment.
2Measurement precision
If the number of antenna elements is increased to improve beam directivity, then beamwidth is reduced and alignment precision requirements increase, but the number of calibration states increases exponentially
Solution Approach 1:
The patent segments the large antenna array into smaller subarrays, making the calibration process manageable. Each subarray has fewer elements, resulting in a much smaller number of calibration states per subarray. The overall system achieves high precision through coordinated calibration of these segmented units rather than attempting to calibrate the entire large array simultaneously.
Solution Approach 2:
The patent introduces a hierarchical calibration structure with multiple levels: individual element calibration, subarray calibration, and full array calibration. This dimensional organization transforms the exponentially complex single-stage calibration problem into a series of manageable stages, reducing overall complexity while maintaining precision.
3Adaptability or versatility
If a codebook with fine granularity is used to cover the field of view, then beam coverage is improved, but the number of required beams and calibration steps increases
Solution Approach 1:
The patent divides the field of view coverage task among multiple subarrays, each responsible for a specific angular sector. Instead of requiring all antenna elements to cover the entire FOV with fine granularity, each subarray covers its designated portion, reducing the number of beams needed per subarray while maintaining overall fine-granularity coverage across the complete field of view.
Data Source
AI summary
An apparatus consisting of hierarchically elaborated antenna modules is calibrated by steps. Although the AWV can be calculated mathematically based on the required phase shift values of each antenna element for a beam direction to compensate for signal delay. However, in practice, due to hardware implementation imperfection, coupling in signal path for each antenna element within hardware, inaccuracies of implementations, physical misalignment, the mathematically generated AWV does not necessarily provide alignment between transmit beam and receive beam. This subset is sufficient is all practical operation. The subset of AWVs are typically called codebook and the receiver beam points to different direction by using a AWV within the codebook.