Multifunctional Broadband Sector Antenna With Folded Strands

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Solution Overview

Problem

Existing antennas struggle to maintain performance and integration on complex structures while operating over a wide frequency band, requiring simultaneous SWR of less than 3, gain greater than 2 dBi, and self-adaptation to impedance without additional matching circuits, especially in VHF/UHF domains.

Innovation Solution

A sectorial antenna design with folded elliptical strands and a ground plane, where the strands are supplied in phase opposition, optimizing curvature and dimensions to stabilize radiation and impedance patterns across a wide frequency range, eliminating the need for external impedance matching circuits.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the antenna size is reduced to facilitate integration, then the ease of manufacture and integration improve, but the standing wave ratio and gain become insufficient to meet quality of service requirements

Engineering Contradiction:
Improveintegration easeVSAvoidSWR and gain performance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent employs curved and folded strand geometries instead of straight linear elements. The strands follow complex three-dimensional paths including folds and curves that increase the effective electrical length within a compact physical footprint, thereby maintaining adequate SWR and gain performance while achieving reduced overall antenna dimensions for easier integration.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The antenna design transitions from planar two-dimensional configurations to three-dimensional folded and curved strand structures. By utilizing vertical and lateral folding, the antenna packs more radiating length into a smaller volume, achieving the necessary electrical performance in a compact form factor suitable for integration-constrained applications.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Reliability

If the antenna size is increased to improve SWR and gain, then the radiation performance improves, but the networking capability and integration become more difficult

Engineering Contradiction:
ImproveSWR and gain performanceVSAvoidnetworking capability
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The folded and curved strand design concentrates the radiating elements into a compact three-dimensional structure, achieving adequate SWR and gain performance without requiring large antenna dimensions. This compact configuration facilitates easier networking and integration while maintaining the necessary radiation performance through optimized curved geometries.

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Adaptability or versatility

If a dipole-loop antenna configuration is used, then the broadband operation is achieved, but an additional impedance matching circuit is required which limits power handling

Engineering Contradiction:
Improvebroadband operationVSAvoidimpedance matching circuit requirement
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The antenna structure achieves broadband operation and impedance matching through its inherent folded and curved geometric configuration rather than requiring external matching circuits. The strand geometry itself provides the necessary impedance transformation and broadband characteristics, enabling the antenna to be self-sufficient and handle higher power levels without additional matching components.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent utilizes variations in strand geometry parameters including fold angles, curve radii, and element spacing to achieve broadband impedance matching directly in the radiating structure. By optimizing these geometric parameters, the antenna achieves wideband operation and proper impedance matching without requiring separate matching circuits, thereby simplifying the overall device and improving power handling capability.

Inventive Principle:
Principle #35Parameter changes

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 antenna achieves stable sector radiation, self-adaptation to impedance, and efficient integration on complex structures with reduced size, maintaining performance and gain across the VHF/UHF bands, enabling omnidirectional coverage and directionality.

Implementation Method 1

comprising a ground plane acting as a reflector plane

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

The two strands are powered in opposite phase

Methodology Applied
Scientific EffectElectromagnetic radiation: Electromagnetic Induction

Data Source

PatentEP3335277B1Multifunctional broadband sector antenna
Publication Date: 2019.11.13 THALES SA
  • EP3335277B1 patent drawingFigure 1~3
  • EP3335277B1 patent drawingFigure 2
  • EP3335277B1 patent drawingFigure 4

AI summary

The invention relates to a broadband or ultra-broadband sector antenna (1) having a height H, a depth D and a width W, including a first ground plane (2) acting as reflective plane, at least one antenna assembly comprising at least one first strand (101) and at least one second strand (102), the antenna operating in a frequency range [f1, f2], characterised in that: one strand (101, 102) has a folded shape, an inner curve F1 starting at a point A positioned towards the centre of the antenna O, and an outer curve F2 forming an extension of the first inner curve F1; the inner curve F1 is determined so as to guarantee the stability of the radiation pattern at the maximum operating frequency of the antenna; the outer curve F2 is determined so as to guarantee the stability of the impedance of the antenna at the supply terminals thereof, at the minimum operating frequency; and the first strand (101) and the second strand (102) are supplied in opposite phase.