Metamaterial Antenna Array Layout for Low-Coupling Isolation
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Solution Overview
Problem
Conventional antenna arrays face challenges in achieving accurate directional angle estimations due to coupling between antenna elements, leading to impedance and radiation pattern issues, which complicates design and requires significant space for ground guard rings, making them unsuitable for devices with limited space.
Innovation Solution
An antenna array utilizing a reactive impedance surface (RIS) layer with metamaterial structures and a ground skirt, which reduces coupling between antenna elements, allowing for a smaller form factor and improved radiation efficiency, while maintaining performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ground guard rings are used to reduce coupling between antenna elements, then isolation between antennas is improved, but the array size increases due to large gaps required
Solution Approach 1:
A reactive impedance surface (RIS) layer with metamaterial structures is introduced as an intermediary between the antenna elements and the ground plane. This RIS layer acts as a mediator that provides electromagnetic isolation and coupling reduction without requiring the large physical gaps traditionally needed between antennas and ground guard rings, thereby maintaining antenna isolation while reducing overall array size
Solution Approach 2:
The patent transforms the ground plane from a simple conductive layer into a reactive impedance surface by incorporating metamaterial structures with specific electromagnetic properties. By changing the electrical parameters of the ground plane through these metamaterial inclusions, the system achieves improved antenna isolation and coupling control without increasing the physical dimensions of the array
2Area of stationary object
If antenna elements are closely spaced to reduce array size, then area is reduced, but coupling between elements increases causing impedance and radiation pattern issues
Solution Approach 1:
The reactive impedance surface serves as a mediator between closely spaced antenna elements, providing electromagnetic isolation that enables tight spacing without excessive coupling. The metamaterial structures in the RIS layer create controlled electromagnetic environments that prevent harmful interactions between adjacent elements while allowing them to be positioned closer together
Solution Approach 2:
The patent applies local electromagnetic property modification by placing specific metamaterial structures in the RIS layer at strategic locations between antenna elements. These localized metamaterial inclusions create regions of controlled impedance and electromagnetic field distribution, reducing coupling in critical areas while maintaining overall array compactness
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
The proposed antenna array achieves better performance with reduced coupling and size, wider bandwidth, and improved radiation efficiency, simplifying design and simulation by using identical antenna unit cells with metamaterial structures and a ground skirt, resulting in more accurate Angle of Arrival and Angle of Departure calculations.
Implementation Method 1
The RIS layer comprises a plurality of metamaterial structures. The metamaterial structures are configured to present an inductance to the patch antennas, thereby allowing the patch antennas to be smaller than would otherwise be possible.
Implementation Method 2
the coupling between the antenna elements causes impedance, radiation pattern and radiation efficiency spreading
Data Source
AI summary
An antenna array that utilizes ground guard rings and metamaterial structures is disclosed. In certain embodiments, the antenna array is constructed from a plurality of antenna unit cells, wherein each antenna unit cell is identical. The antenna unit cell comprises a top surface, that contains a patch antenna and a ground guard ring. A reactive impedance surface (RIS) layer is disposed beneath the top surface and contains the metamaterial structures. The metamaterial structures are configured to present an inductance to the patch antennas, thereby allowing the patch antennas to be smaller than would otherwise be possible. In some embodiments, the metamaterial structures comprise hollow square frames. An antenna array constructed using this antenna unit cell has less coupling than conventional antenna arrays, which results in better performance. A ground skirt surrounds the perimeter of the antenna array to improve radiation phase pattern balance within the array.