Quasi-Random Antenna Array Layout to Limit Aliasing Effects
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Solution Overview
Problem
Conventional antenna array manufacturing methods for over-the-air measurement applications face challenges in increasing the size of the quiet zone while maintaining measurement accuracy, often resulting in high costs and complexity due to the use of multiple antennas arranged on a rectangular grid, which suffer from aliasing effects when determining far-field properties from near-field measurements.
Innovation Solution
The method involves arranging antennas in a quasi-random fashion using algorithms like blue noise, Poisson disc, or low discrepancy sampling to reduce aliasing effects, allowing for a significant reduction in the number of antennas required, up to 60%, without compromising measurement accuracy, by determining quasi-random positions based on predefined criteria and transforming them into spatial frequency domains for optimal performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If antennas are arranged on a rectangular grid to form a plane wave converter, then the antenna array can measure electromagnetic waves in the near-field area, but aliasing effects occur when determining far-field properties from near-field measurements
Solution Approach 1:
The patent applies asymmetry by transitioning from a symmetric rectangular grid arrangement to an asymmetric quasi-random arrangement of antennas. This asymmetric positioning eliminates the periodic structure that causes aliasing effects in the spatial frequency domain, while still maintaining sufficient sampling density to accurately capture near-field electromagnetic wave characteristics for far-field property determination.
Solution Approach 2:
The patent addresses the aliasing problem by considering the spatial frequency domain (another dimension) rather than only the physical space arrangement. By analyzing and optimizing the distribution in the spatial frequency domain, the patent achieves an antenna configuration that avoids aliasing while maintaining measurement accuracy.
2Area of stationary object
If multiple antennas are used to create a plane-like wave front, then the quiet zone size can be increased, but the cost and complexity of the antenna array increase
Solution Approach 1:
The patent applies parameter changes by optimizing the antenna positions based on spatial frequency domain criteria rather than using a fixed grid pattern. This allows achieving the same or better quiet zone coverage with fewer antennas by strategically placing them where they provide maximum information content for far-field property determination.
Solution Approach 2:
The patent uses algorithms to generate optimal antenna position configurations that replicate the benefits of dense grid arrangements while using fewer physical antennas. The quasi-random positions are designed to capture the essential spatial frequency information needed for accurate far-field measurements.
3Ease of manufacture
If a rectangular grid arrangement is used for antennas, then the manufacturing process is simplified, but the number of antennas required increases significantly
Solution Approach 1:
The patent applies preliminary action by pre-calculating optimal antenna positions using algorithms that consider spatial frequency domain requirements. These pre-determined quasi-random positions are then used for manufacturing, combining the precision of algorithmic optimization with the simplicity of following a predetermined layout, thereby reducing the number of antennas needed while maintaining ease of manufacture.
Data Source
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AI summary
A method for manufacturing an antenna array (14) is described. The method comprises the following steps: - providing several antennas (20); - determining at least one set of quasi-random positions for the antennas (20) based on a predefined algorithm for limiting aliasing effects, wherein the positions are arranged on a manifold having at least one dimension in an irregular manner; and - arranging the antennas (20) according to the at least one set of quasi-random positions obtained from the predefined algorithm for limiting aliasing effects. Further, an antenna array (14) and a test system (10) are described.