Sphere Antenna with Nested Planar Assemblies for Compact Direction-Finding
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Solution Overview
Problem
Existing direction-finding antennas face challenges in providing extensive three-dimensional coverage and operating in a wide frequency band, particularly in the VHF and UHF domains, due to complexity in defining conductive cable passages and limitations imposed by the use of electrically small loops or short dipoles, which restricts radioelectric performance and compactness.
Innovation Solution
A sphere antenna design featuring planar assemblies of sectoral radiation patterns with folded-loaded dipoles, arranged to provide multi-sectoral and multi-polarization operation, allowing for extended spatial coverage and compactness, enabling operation across a wide frequency band from 30 MHz to 3000 MHz.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional antenna systems are integrated on carriers for on-board operation, then direction-finding capability is achieved, but compactness constraints cannot be complied with
Solution Approach 1:
Multiple planar assemblies are nested or closely integrated in three-dimensional space, with each assembly occupying a compact volume while contributing to overall directional coverage. The folded-loaded dipole structures are nested within the planar assembly framework, achieving maximum radiation capability within minimum volume, thus satisfying on-board compactness constraints.
Solution Approach 2:
The antenna system utilizes three-dimensional spatial arrangement of planar assemblies rather than planar expansion, transitioning from two-dimensional layout to three-dimensional configuration. This dimensional change enables comprehensive directional coverage while maintaining compact footprint suitable for carrier integration.
2Adaptability or versatility
If extensive elevation and polarization coverage is required for direction-finding applications, then electromagnetic field measurements in different directions are achieved, but antenna system complexity increases
Solution Approach 1:
Each planar assembly is designed with multi-functionality to handle multiple polarizations and spatial sectors simultaneously. The folded-loaded dipole structures provide universal response to both electric and magnetic field components across multiple polarizations, reducing the need for separate specialized elements and thereby managing system complexity while achieving extensive coverage.
Solution Approach 2:
Different planar assemblies are positioned and oriented to provide specialized local coverage for specific elevation angles and polarization types. Each assembly is locally optimized for its designated spatial sector, with the collective arrangement providing comprehensive global coverage. This local specialization approach manages complexity by dividing the coverage task among optimized local units.
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 sphere antenna achieves enhanced spatial coverage and radioelectric performance across a wide frequency band, addressing the limitations of existing antennas by ensuring compactness and efficient operation in direction-finding applications, particularly in the VHF and UHF domains.
Implementation Method 1
a sphere antenna (2) adapted to operate in a wide band of frequencies, in particular in the VHF and UHF domains
Implementation Method 2
Each strand (12, 14) is formed from an electrically conductive material
Data Source
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AI summary
The invention relates to a spherical antenna (2) adapted to operate over a wide frequency band, adapted to transmit/receive electromagnetic radiation in a plurality of spatial directions, and composed of a plurality of radiating elements. This antenna (2) comprises three planar sets of motifs (301, 302, 303) having the same center of symmetry, arranged in three pairwise orthogonal planes of space. Each planar set of motifs (301, 302, 303) comprises at least four radiating elements, forming elementary motifs with sectoral radiation, arranged symmetrically in pairs with respect to axes of symmetry intersecting said center of symmetry. The arrangement of the three planar sets is carried out such that none of the elementary motifs is intersected by another elementary motif.