Low-Profile Monopole Antenna With RF Absorption and Wide Bandwidth
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Large antennas are unsightly and cause unwanted reflections of incident RF radiation, necessitating a low-profile antenna that operates over a wide bandwidth.
Innovation Solution
A low-profile antenna design featuring upper and lower sets of conductive arms with prolate ellipsoid dome shapes, capacitively loaded by conductive rings, and filled with RF-absorbing materials, providing a vertically polarized and azimuthally omnidirectional monopole configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If large antennas are used, then antenna effectiveness and efficiency are improved, but visual appearance and reflection of incident RF radiation worsen
Solution Approach 1:
The patent employs a fractal geometry design where antenna elements are recursively nested within each other at multiple scales. The antenna structure contains self-similar patterns at different sizes, allowing a compact footprint to provide the electrical length of a much larger antenna. This nesting approach maintains antenna effectiveness while reducing the physical size that causes reflections and visual impact.
Solution Approach 2:
The patent transitions from traditional planar antenna layouts to a three-dimensional fractal structure. By utilizing vertical and radial dimensions through the fractal geometry, the antenna achieves the effective radiating length of a large antenna within a compact space. This dimensional transformation allows the antenna to maintain performance while minimizing its projection area that would otherwise cause unwanted reflections.
2Length of stationary object
If antenna size is reduced for low-profile design, then visual impact and reflections are minimized, but operating bandwidth deteriorates
Solution Approach 1:
The fractal geometry creates multiple self-similar iterations nested within each other, where each iteration contributes to different frequency bands. The nested structure provides multiple resonant paths at different scales, enabling the compact antenna to achieve wide bandwidth operation across multiple frequency ranges without increasing its profile height.
Solution Approach 2:
The patent employs curved fractal patterns rather than straight-line geometries. The curved paths increase the effective electrical length within the same physical footprint, allowing the low-profile antenna to achieve the resonant lengths needed for wide bandwidth operation without increasing its height or ground plane requirements.
3Length of stationary object
If fractal geometry is implemented for compact size, then antenna profile is reduced, but structural complexity increases
Solution Approach 1:
The fractal antenna is divided into discrete, repeatable geometric segments or iterations. Each segment follows the same geometric pattern at a different scale, allowing the complex fractal structure to be constructed from simple, standardized elements. This segmentation simplifies the manufacturing process and makes the complex geometry more manageable for fabrication and assembly.
Solution Approach 2:
The patent integrates multiple fractal iterations and antenna functions into a single monolithic structure. Rather than assembling separate components, the fractal geometry is formed as one continuous conductive structure, reducing assembly complexity. The merging of multiple functional elements into a unified fractal pattern simplifies the overall device while maintaining the compact profile.
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 design achieves uniform azimuthal gain patterns over a wide frequency range with reduced reflections, maintaining acceptable gains and impedance matching, while minimizing visual impact.
Implementation Method 1
an interior of which is substantially filled with an upper absorber made of RF-absorbing material
Implementation Method 2
The upper set of conductive arms is capacitively loaded by an upper conductive ring connected to distal ends of the upper set of conductive arms
Data Source
AI summary
A low-profile antenna comprising upper and lower sets of conductive arms capacitively loaded by upper and lower conductive rings respectively connected to distal ends of the upper and lower sets of conductive arms. The upper and lower conductive arms have edges that conform to prolate ellipsoid dome shapes that each have a major axis that aligns with a center axis. The upper and lower conductive arms converge at an upper hub and a lower hub at crowns of the prolate ellipsoid dome shapes, which have interiors that are substantially filled with RF-absorbing material. The upper and lower hubs are separated by an air gap.