Multi-Element Antenna Array Testing Without Anechoic Chambers
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Solution Overview
Problem
Conventional methods for testing multi-element antenna arrays require expensive and inconvenient anechoic chambers to determine far field radiation patterns, limiting efficient factory testing.
Innovation Solution
A method and apparatus using a movable probe in a second plane parallel to the antenna elements, measuring electromagnetic energy at positions less than a quarter wavelength apart, allowing direct determination of far field radiation patterns without anechoic chambers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional anechoic chamber methods are used to measure far field radiation patterns, then measurement accuracy is improved, but testing cost and convenience deteriorate
Solution Approach 1:
The patent introduces a movable probe as an intermediary device that measures electromagnetic fields in the near field region. This probe serves as a mediator between the antenna array and the measurement system, enabling far field pattern determination without requiring far field conditions or anechoic chambers. The probe collects near field data that is then transformed to obtain far field radiation patterns.
Solution Approach 2:
The patent replaces the mechanical/physical anechoic chamber environment with a computational approach. Instead of using physical absorptive materials and far field measurement distances, the system uses near field measurements combined with mathematical transformations (such as near field to far field transformation algorithms) to determine far field radiation patterns, eliminating the need for expensive anechoic chamber facilities.
2Reliability
If an anechoic chamber is used to reduce radiation interference, then measurement reliability is improved, but device complexity and cost increase
Solution Approach 1:
The patent transitions from measuring in the far field region to measuring in the near field region, effectively changing the spatial dimension of measurement. By moving the measurement plane closer to the antenna array and utilizing near field electromagnetic field characteristics, the system achieves reliable far field pattern determination without requiring far field measurement conditions or complex anechoic chamber environments.
3Measurement precision
If near field measurements are taken as far as possible from the antenna, then transformation accuracy is improved, but radiation interference from multiple elements increases
Solution Approach 1:
The patent applies local quality by using a movable probe that can be positioned at specific locations in the near field region. The probe measures electromagnetic fields locally at different positions, and by systematically moving through the near field space, it collects localized field information that can be transformed to obtain accurate far field patterns while minimizing interference effects from multiple antenna elements.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables accurate and efficient factory testing of multi-element antenna arrays by reducing radiation interference and eliminating the need for anechoic chambers, facilitating identification and correction of faulty elements.
Implementation Method 1
causing the movable probe to radiate electromagnetic energy
Data Source
AI summary
A far field radiation pattern is determined for a multi-element antenna array comprising a plurality of antenna elements in a first plane using test apparatus comprising a support member for holding the array and a movable probe having an aperture configured to move in a second plane parallel to the first. A distance between the first and second plane is less than a quarter of a wavelength at an operating frequency of the antenna array. The movable probe radiates electromagnetic energy from the aperture and is moved in a determined trajectory in the second plane. A respective measurement of amplitude and phase of electromagnetic energy received by the antenna array is taken at a plurality of positions on the determined trajectory. The far field radiation pattern is determined from the respective measurements and from a pre-determined radiation pattern for at least one antenna element of the plurality of antenna elements.