Antenna Array OTA Measurement with Near-Field Phase Compensation
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Solution Overview
Problem
Existing over-the-air measurement systems for antenna arrays in 5G communications are bulky and costly due to the need for far-field measurements, which are not suitable for large-scale deployment and require complex mounting and maintenance.
Innovation Solution
A method and system that aligns the phases and amplitudes of electromagnetic waves from multiple antenna groups using compensation values to achieve coherent superposition at a measurement probe within a short distance, allowing for equivalent far-field measurements in a compact setup.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If far-field measurement is used to obtain accurate over-the-air beam indicator, then measurement precision is improved, but the space occupied by the measurement system increases and device complexity increases
Solution Approach 1:
A spherical wave to plane wave converting component is introduced as an intermediary element between the antenna array and measurement probe. This component transforms the spherical wave emitted by the antenna array into a plane wave, enabling far-field measurement conditions to be achieved within a short distance without requiring large measurement space.
Solution Approach 2:
The measurement system changes the wavefront parameter from spherical to plane wave through the converting component. This parameter transformation allows the system to achieve far-field measurement characteristics (plane wavefront) at near-field distances, resolving the contradiction between measurement accuracy and space occupation.
2Area of stationary object
If spherical wave is converted into plane wave through collimating component to reduce space, then measurement space is reduced, but manufacturing precision requirements increase and device complexity increases
Solution Approach 1:
The antenna array is divided into multiple independently controllable antenna units, each capable of independent phase and amplitude adjustment. This segmentation allows digital beamforming techniques to be applied, where the collimating function is achieved through software-controlled phase shifting rather than requiring high-precision mechanical collimating components.
Solution Approach 2:
The mechanical/optical collimating component is replaced with a digital signal processing system. Instead of using physical components to transform spherical waves to plane waves, the system uses electronic phase and amplitude control of individual antenna elements to achieve the same effect, eliminating manufacturing precision requirements for optical/mechanical collimating components.
3Area of stationary object
If collimating component is used to achieve far-field measurement in short distance, then measurement space is reduced, but ease of manufacture decreases and ease of operation decreases
Solution Approach 1:
The antenna units serve multiple functions: they act as both radiating elements and phase-shifting elements. Each antenna unit can independently control its phase and amplitude, eliminating the need for separate collimating components and simplifying the overall system structure, making it easier to manufacture and maintain.
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
Reduces measurement costs and system size while maintaining accuracy, enabling wide deployment and achieving accurate far-field measurement results in a medium or near field.
Implementation Method 1
adjust phases and amplitudes of the electromagnetic waves transmitted by the antenna units, so that the electromagnetic waves have aligned phases and amplitudes when the electromagnetic waves are coherently superposed
Data Source
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AI summary
Embodiments of this application disclose a measurement method and a device, and relate to the communications field, to reduce measurement costs while achieving an equivalent far-field measurement effect within a short distance by using a small-sized measurement system, helping deploy the measurement system widely. The method includes: for each antenna group other than a target antenna group in an antenna array, determining compensation values of the antenna group based on characteristic parameters of the antenna group and characteristic parameters of the target antenna group, and adjusting, based on the compensation values of the antenna group, an electromagnetic wave transmitted by each antenna unit in the antenna group, so that electromagnetic waves transmitted by all antenna units in the antenna array have a same phase and/or amplitude when the electromagnetic waves arrive at a measurement probe of a second device, where the electromagnetic wave is used to measure an over-the-air beam parameter of the first device, and a distance between the first device and the measurement probe is less than a far-field boundary distance.