Squinted Feed Layout in Lens Array Antennas for Side Lobe Control
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Solution Overview
Problem
Multiple beam antenna arrays face challenges with poor beam-to-beam isolation due to coupling from non-radiating and radiating network components, leading to increased signal interference and VSWR alarms, while traditional methods like Butler Matrix result in inadequate side lobe reduction.
Innovation Solution
The use of spherical lens arrays with rotating feeds to reduce azimuth side lobes and maintain consistent beam width across a wide frequency band, leveraging meta-materials and phase shifting techniques for improved beam isolation and signal integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple feeds are placed behind a single lens to increase beam count, then the number of beams increases, but beam-to-beam isolation deteriorates due to coupling from network components
Solution Approach 1:
The patent divides the single lens into multiple spherical sub-lenses, with each sub-lens handling a specific beam. This segmentation isolates the feed networks for each beam, reducing coupling between adjacent beams while maintaining the ability to generate multiple beams simultaneously.
Solution Approach 2:
The patent introduces spherical sub-lenses as intermediary elements between the feed network and the radiation space. These sub-lenses act as independent beam-forming units that reduce direct coupling between feed networks while maintaining beam-to-beam isolation through their spherical geometry and positioning.
2Ease of operation
If Butler Matrix is used for beam switching, then beam routing is achieved, but side lobe levels increase and beam isolation remains insufficient
Solution Approach 1:
The patent extracts the beam routing function from the traditional Butler Matrix and implements it directly through the spherical sub-lens array configuration. Each sub-lens is independently positioned and fed to achieve beam switching without requiring a complex Butler Matrix, thereby eliminating the side lobe issues associated with matrix-based beam switching.
Solution Approach 2:
The patent replaces the mechanical/electrical beam switching system (Butler Matrix) with a geometric/optical system using spherical sub-lenses. The beam routing is achieved through the physical positioning and optical properties of the sub-lenses rather than through electrical switching networks, reducing side lobe generation.
3Ease of manufacture
If feeds are placed on flat plate antenna, then manufacturing is simplified, but scan angle performance and beam tilt capability are compromised
Solution Approach 1:
The patent replaces the flat plate geometry with spherical sub-lenses. The spherical curvature allows feeds to be positioned on the surface of the lens without compromising performance, enabling wide scan angles and beam tilt capability while maintaining manufacturing feasibility through modular lens assembly.
4Productivity
If beam spacing is reduced to increase beam density, then coverage capacity increases, but beam cross over level deteriorates and interference increases
Solution Approach 1:
The patent applies local quality by giving each spherical sub-lens its own dedicated feed network and optimizing its individual positioning and illumination. This localized optimization allows tight beam spacing while maintaining high beam cross-over levels through precise control of each sub-lens's radiation pattern and feed placement.
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 effectively reduces azimuth side lobes and maintains consistent beam performance, enhancing signal-to-interference-plus-noise ratio and reducing unwanted signal transmission, thereby improving network capacity and reliability.
Implementation Method 1
Lens based antennas using light weight dielectric material have seen a growing market for several applications including base station antennas, stadium antennas, special event antennas, and satellite tracking antennas.
Implementation Method 2
Spherical lenses allow feeds to be placed and moved around the surface of the lens without compromising performance due to scan angle or beam tilt angle.
Implementation Method 3
The use of spherical lens arrays with rotating feeds to reduce azimuth side lobes and maintain consistent beam width across a wide frequency band, leveraging meta-materials and phase shifting techniques for improved beam isolation and signal integrity.
Implementation Method 4
leveraging meta-materials and phase shifting techniques for improved beam isolation and signal integrity.
Data Source
AI summary
A radio frequency antenna array uses lenses and RF elements, to provide ground-based coverage for cellular communication. The antenna array can include two spherical lenses, where each spherical lens has at least two associated RF elements. Each of the RF elements associated with a given lens produces an output beam with an output area. Each lens is positioned with the other lenses in a staggered arrangement. The antenna includes a control mechanism configured to enable a user to move the RF elements along their respective tracks, and automatically phase compensate the output beams produced by the RF elements based on the relative distance between the RF elements.