MIMO Antenna Eigenvector Feeding Decoupling
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Solution Overview
Problem
Existing MIMO antenna systems face challenges in achieving low correlation between antenna ports, which is crucial for efficient data throughput and reliability, especially in compact devices like handsets, due to geometrical and mechanical constraints, and near-field coupling with the user's body disrupts symmetry.
Innovation Solution
The implementation of a MIMO antenna system that uses eigenvector-based feeding profiles derived from a mathematical representation of the antenna system, allowing for uncorrelated 'antenna modes' with distinct efficiencies, achieved through an active feeding network with programmable gains and time delays, enabling complex weight applications to optimize antenna performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If antenna ports are decoupled by separating antenna elements physically or placing them orthogonal to each other, then electrical coupling between antenna ports is reduced, but geometrical and mechanical constraints are imposed on the handset architecture
Solution Approach 1:
The patent replaces mechanical/physical decoupling approaches with a mathematical transformation approach. Instead of physically separating or orthogonally positioning antenna elements, the invention uses a transformation matrix to convert correlated antenna ports into uncorrelated eigen-ports, substituting mechanical constraints with signal processing solutions.
Solution Approach 2:
The patent changes the feeding parameters of the antenna ports by applying complex weights through a transformation matrix. This transforms the original antenna port parameters into new eigen-port parameters that achieve decoupling without altering the physical antenna structure or positioning.
2Reliability
If antenna elements are fed in even and odd fashion to decouple antenna ports, then electrical coupling is reduced, but the device must feature substantially mirror-like symmetries
Solution Approach 1:
The patent generalizes the even/odd feeding concept by using a transformation matrix that can handle any antenna configuration, not just symmetric ones. The complex weight parameters are adjusted based on the specific antenna coupling characteristics, allowing decoupling without requiring mirror-like symmetries in the device architecture.
3Volume of stationary object
If MIMO antenna systems are implemented under volume constraints, then compact device design is achieved, but proper antenna isolation becomes difficult
Solution Approach 1:
The patent substitutes physical isolation mechanisms with mathematical transformation. Instead of increasing physical distance or using isolation structures between antenna elements, the invention uses a transformation matrix to create uncorrelated eigen-ports, achieving isolation through signal processing rather than physical separation.
Solution Approach 2:
The patent transforms the antenna port parameters using complex weights to achieve decoupling in the electrical domain, allowing compact physical arrangements while maintaining proper antenna isolation through parameter transformation rather than physical separation.
4Adaptability or versatility
If near-field coupling with user's body occurs, then symmetries are disrupted, but antenna performance degrades
Solution Approach 1:
The patent measures the actual coupling characteristics between antenna ports and uses this information to determine the appropriate transformation matrix. This feedback mechanism allows the system to adapt to changes in the electromagnetic environment, including near-field coupling with the user's body, and maintain optimal performance by adjusting the feeding parameters accordingly.
Data Source
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AI summary
An antenna system includes a multi-port antenna with an active feeding network coupled thereto. The active feeding network applies complex weights to signals received from and transmitted to each port of the multi-port antenna. The complex weights are applied according to eigenvectors corresponding to a Hermitian matrix representation of the multi-port antenna. The Hermitian matrix may be base on such multi-port antenna parameters such as power dissipation, power radiation, real-power flow, volumetric storage of electromagnetic energy, and/or volumetric dissipation of electromagnetic energy. The multi-port antenna yields orthogonal electromagnetic fields in volumes or surfaces of interest in response to the active feeding network excitation.