Spherical Lens Multi-Beam MIMO Antenna With Wideband Beam Tilt
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Solution Overview
Problem
Current wireless communication systems face challenges in increasing capacity due to poor isolation between antenna ports in MIMO and multi-beam antennas, which limits their ability to provide wideband MIMO performance required for modern and future cellular communications.
Innovation Solution
The use of a spherical RF lens to combine MIMO and multi-beam technologies, resulting in a compact, wideband, and multi-band base station antenna with high isolation between ports, enabling high-order MIMO capabilities such as 4×4 and 8×8 configurations, and allowing for asymmetric beam formation through tilting, offsetting, and phase shifting of radiating elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If absorber material is used for isolation between antenna ports, then isolation between antenna ports is improved, but signal degradation and passive inter-modulation issues occur
Solution Approach 1:
The patent removes the absorber material from the antenna system entirely. Instead of using absorber material between antenna ports, the invention employs a spherical lens element that provides both beam forming and isolation functions through its dielectric properties and geometric configuration, eliminating the harmful effects of absorber material while maintaining port isolation.
Solution Approach 2:
The spherical lens element serves multiple functions simultaneously: it forms multiple beams in different directions, provides isolation between antenna ports through its dielectric constant and physical positioning, and enables wideband operation. This multi-functional approach replaces the need for separate absorber materials and beam-forming structures.
2Adaptability or versatility
If conventional MIMO antennas are used, then MIMO capability is provided, but the antenna becomes bulky and lacks multi-beam functionality
Solution Approach 1:
The patent merges MIMO capability and multi-beam functionality into a single integrated antenna structure. Multiple radiating elements are positioned around the spherical lens, with each element contributing to multiple beams through the lens's focusing properties. This combination achieves both high-order MIMO (4×4, 8×8) and multi-beam operation in a compact form factor.
Solution Approach 2:
The spherical lens introduces a three-dimensional geometric element that enables compact arrangement of multiple radiating elements in space. By utilizing the spherical geometry and positioning elements at different radial distances and angular positions, the patent achieves high isolation and multi-beam formation without requiring large planar arrays, thus reducing overall antenna volume.
3Volume of moving object
If multi-beam antennas based on spherical lens are used, then multi-beam capability and compact size are achieved, but isolation between antenna ports is insufficient
Solution Approach 1:
The patent optimizes the local electromagnetic environment around each radiating element by carefully selecting the dielectric constant of the spherical lens material and positioning elements at specific radial distances. This local optimization of dielectric properties and spatial arrangement enhances isolation between antenna ports while maintaining compact dimensions and multi-beam performance.
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 solution significantly increases communication system capacity by providing more than 10 times the capacity of regular one-port antennas, with isolation exceeding 27 dB in a wide operational frequency band, and allows for flexible beam shaping to optimize cell coverage and reduce interference.
Implementation Method 1
The use of a spherical RF lens to combine MIMO and multi-beam technologies
Implementation Method 2
spherical RF lens allows for marriage of MIMO and multi-beam technologies
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.