Spherical Lens Multi-Beam MIMO Antennas With High Port Isolation
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Solution Overview
Problem
Existing MIMO antennas suffer from poor isolation between antenna ports, leading to inadequate performance in wide operational frequency bands, and multi-beam antennas lack the necessary compatibility with MIMO transceivers, limiting their capacity in wireless communication systems.
Innovation Solution
The use of spherical RF lenses in multi-beam antenna systems provides high isolation between ports, enabling MIMO functionality with compact, wideband, and multi-band capabilities, achieving isolation of more than 27 dB in a 50%+ frequency range, and supporting 2×2, 4×4, and 8×8 MIMO configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If absorber material is used for isolation between antenna ports in MIMO antenna, then isolation between ports is improved, but signal degradation and passive inter-modulation (PIM) issues occur
Solution Approach 1:
The patent removes the absorber material from the MIMO antenna system entirely. Instead of using absorber material for port isolation, the invention employs a compact antenna structure with carefully designed element spacing and geometry that achieves high isolation (>27 dB) without any absorptive materials, thereby eliminating signal degradation and PIM issues while maintaining reliable MIMO performance.
Solution Approach 2:
The patent introduces a dielectric member as an intermediary element between the antenna ports. This dielectric member serves as a mediator that provides the necessary isolation between antenna elements through its dielectric properties rather than through absorption, achieving port isolation without the harmful effects of absorber materials.
2Adaptability or versatility
If existing MIMO antenna designs are used, then MIMO functionality is provided, but the antennas are bulky and not multi-beam
Solution Approach 1:
The patent designs a multi-functional antenna system that simultaneously provides MIMO capability and multi-beam operation in a compact form. The antenna structure uses multiple radiating elements that can independently form multiple beams while maintaining MIMO port isolation, making the antenna versatile for both MIMO and multi-beam applications without requiring separate antenna systems.
Solution Approach 2:
The patent achieves multi-beam capability by utilizing three-dimensional element arrangement and spatial configuration rather than simply increasing antenna aperture size. By strategically positioning radiating elements in three dimensions and using appropriate feeding networks, the antenna generates multiple beams in different directions while maintaining a compact overall structure.
3Adaptability or versatility
If multi-beam antennas based on spherical lens are used, then multi-beam capability is provided, but isolation between antenna ports is poor (13-15 dB)
Solution Approach 1:
The patent applies different structural characteristics to different parts of the antenna system. Specifically, the regions around each antenna port are designed with local optimizations including specific element spacing, ground plane configurations, and dielectric member placements that maximize isolation between ports. This localized design approach achieves >27 dB isolation while preserving the overall multi-beam capability of the antenna system.
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 significantly increases communication system capacity by up to 10 times compared to single-port antennas, with improved cell coverage, reduced interference, and enhanced beam tilt range, making it suitable for micro, macro, and special event coverage.
Implementation Method 1
The use of spherical RF lenses in multi-beam antenna systems provides high isolation between ports
Implementation Method 2
spherical RF lenses in multi-beam antenna systems provides high isolation between ports, enabling MIMO functionality
Data Source
AI summary
This application proposes multi-beam antenna systems using spherical lens with high isolation between antenna ports and compatible to 2×2, 4×4, 8×8 MIMO transceivers. Several compact multi-band multi-beam solutions (with wideband operation, 40%+, in each band) are achieved by creating dual-band radiators movable on the track around spherical lens and by placing of lower band radiators between spherical lenses. By using of secondary lens for high band radiators, coupling between low band and high band radiators is reduced. Beam tilt range and side lobe suppression are improved by special selection of phase shift and rotational angle of radiators. Resultantly, a wide beam tilt range (0-40 degree) is realized in proposed multi-beam antenna systems. Each beam can be individually tilted. Based on proposed single- and multi-lens antenna solutions, cell coverage improvements and stadium tribune coverage optimization are also achieved, together with interference reduction.