Antenna Subarray Calibration Using Mutual Coupling and Couplers
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Solution Overview
Problem
Existing massive MIMO technologies face high costs and complexity due to calibration networks in antennas, which often require electrical shielding, leading to increased complexity and cost.
Innovation Solution
An antenna design that utilizes mutual coupling between subarrays of dual polarized radiator elements, employing couplers to flatten the frequency response of coupling signals for phase calibration, eliminating the need for separate calibration networks and reducing complexity and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a calibration network is used in the antenna for phase calibration, then calibration accuracy is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts the calibration function from a separate calibration network and integrates it into the existing antenna feeding structure. By using the existing signal paths and adding only minimal coupling elements, the calibration functionality is obtained without the complexity of a dedicated calibration network, thus reducing device complexity while maintaining calibration accuracy.
Solution Approach 2:
The patent makes the existing feeding network serve dual purposes: both signal transmission and calibration. The same signal paths used for normal operation are also used for calibration by introducing coupling signals, eliminating the need for separate calibration hardware and reducing overall device complexity.
2Reliability
If a calibration network with electrical shielding is implemented, then signal quality is improved, but cost and complexity increase
Solution Approach 1:
The patent utilizes the existing shielded structure of the antenna feeding network to protect calibration signals. The same physical enclosure that protects transmission signals also protects calibration signals, eliminating the need for additional shielding structures and reducing both cost and complexity.
3Device complexity
If mutual coupling calibration is used without couplers, then device complexity is reduced, but frequency response accuracy deteriorates
Solution Approach 1:
The patent introduces couplers as intermediary elements that facilitate accurate mutual coupling calibration. These couplers act as mediators between the antenna elements, providing controlled coupling paths that flatten the frequency response and improve measurement accuracy without significantly increasing overall system complexity.
Solution Approach 2:
The patent modifies the coupling characteristics by introducing couplers with specific coupling coefficients designed to flatten the frequency response. By changing the coupling parameters appropriately, the frequency response accuracy is improved while keeping the calibration structure relatively simple.
4Adaptability or versatility
If separate feedback branch is added for calibration, then calibration functionality is improved, but device complexity increases
Solution Approach 1:
The patent makes the existing feedback paths serve dual purposes by using them for both normal signal processing and calibration. The same feedback branches that receive transmission signals are also used to receive calibration signals, eliminating the need for separate feedback hardware and reducing device complexity.
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
This approach improves antenna performance by enhancing calibration accuracy and reducing costs and complexity, allowing for precise beamforming without the need for separate calibration modes.
Implementation Method 1
a first coupler electrically coupling the first dual polarized radiator element and the second dual polarized radiator element to each other
Implementation Method 2
a coupling signal generatable, during operation of the antenna, between the first subarray and the second subarray
Data Source
AI summary
An antenna comprising first and second dual polarized radiator elements forming a first subarray, and third and fourth dual polarized radiator elements forming a second subarray. The antenna further comprises a calibration unit coupled to the first and second subarrays that is configured, based on a coupling signal generatable, during operation of the antenna, between the first and second subarrays, to generate or receive a calibration signal for calibrating one or both of the first subarray with respect to the second subarray and the second subarray with respect to the first subarray. The antenna further comprises one or both of (i) a first coupler electrically coupling the first and second dual polarized radiator elements to each other, and (ii) a second coupler electrically coupling the third and fourth dual polarized radiator elements to each other. A said coupler is configured to flatten a frequency response of the coupling signal.