Self-Grounded Multiport Antenna for MIMO Isolation
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Solution Overview
Problem
Current wideband antennas are inadequate for multiport MIMO communication systems due to issues with compactness, angular coverage, radiation efficiency, and polarization schemes, particularly in environments with multipath fading effects, and there is a lack of compact multiport antennas with low mutual coupling between ports.
Innovation Solution
A multiport UWB antenna arrangement with weak mutual coupling between ports, ensuring orthogonal far-field functions in terms of polarization, direction, or shape, which is easy to fabricate and cost-effective, suitable for micro base stations and measurement systems, including those with MIMO capability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional wideband antennas are used, then they provide basic radiation functionality, but they exhibit high mutual coupling between ports and fail to provide low correlation for MIMO systems
Solution Approach 1:
The antenna is divided into multiple arm sections (first, second, third, fourth arm sections) that are bent backwards onto opposite sides of the central portion. Each arm section functions as a separate radiating element with its own port, creating a multiport antenna structure that provides low mutual coupling between ports while maintaining compact form factor.
Solution Approach 2:
The arm sections are bent backwards in three-dimensional space onto opposite sides of the central portion, utilizing spatial arrangement to achieve low mutual coupling. This 3D configuration allows the antenna to maintain a compact profile while providing the necessary port isolation for MIMO applications.
2Volume of moving object
If compact antenna design is implemented, then low profile and small size are achieved, but angular coverage and radiation efficiency are reduced
Solution Approach 1:
The antenna structure is segmented into multiple arm sections that can be independently configured. These sections are arranged to provide omnidirectional radiation patterns while maintaining a compact overall size, achieving both small volume and wide angular coverage simultaneously.
Solution Approach 2:
The antenna design provides multiple functions: it serves as a compact radiating element, achieves omnidirectional coverage, provides low mutual coupling for MIMO, and maintains low profile. The multi-functional design allows a single antenna structure to satisfy multiple conflicting requirements.
3Adaptability or versatility
If multiport antenna configuration is used, then MIMO capability is enabled, but ohmic losses and impedance mismatch increase
Solution Approach 1:
Each arm section is independently optimized with specific geometric characteristics to minimize ohmic losses. The local configuration of each radiating element is designed to achieve optimal current distribution and impedance matching, reducing losses while maintaining multiport functionality.
Solution Approach 2:
The antenna design allows optimization of various parameters including arm section dimensions, bending angles, and spacing to minimize ohmic losses and improve impedance matching. By adjusting these parameters, the antenna achieves low losses while maintaining MIMO capability.
4Ease of operation
If directional antenna patterns are implemented, then spatial selectivity is improved, but omnidirectional coverage is lost
Solution Approach 1:
The arm sections are bent backwards onto opposite sides of the central portion in an asymmetric configuration that creates omnidirectional radiation patterns. This asymmetric arrangement in three-dimensional space provides uniform coverage in all horizontal directions while maintaining spatial selectivity through the specific geometric configuration.
Data Source
AI summary
A self-grounded antenna arrangement includes a base or central portion in a first plane and a number of arm sections associated with the central portion that taper toward a respective end tip. Each arm section is adapted to form a transition from the central portion and being bent backward toward the central portion by more than 180 degrees so that its end tip approaches a first side of the central portion, at an opening in the central portion. The end tip is connected to a feeder configured to feed, via an arm-section-specific port, one specific port for each arm section. Each arm section has a mixed functionality of a curved monopole antenna and a loop antenna, and the antenna arrangement provides substantially uncoupled ports with far-field functions that are almost orthogonal in polarization, direction, or shape. The arrangement finds use in multiple-input multiple-output antenna systems for statistical multipath environments.