Dual-loop Antenna for Submersible High-Power Communication

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Solution Overview

Problem

Existing submersible antennas face issues with mechanical and electrical damage during deployment and rewinding, and have low radio efficiency and limited power transmission capabilities, making them unsuitable for high-frequency data transmission between submersible vehicles and land bases.

Innovation Solution

A bi-loop antenna system with symmetrical loops supplied in phase opposition, isolated by a dielectric enclosure, which reduces ohmic losses and allows for high-power transmission by canceling out return currents, and optionally incorporates a ferromagnetic core to minimize size while maintaining efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a wire antenna is towed behind a submersible and floated on the surface, then high-frequency transmission is enabled, but the antenna cable is susceptible to mechanical breakage during deployment and rewinding

Engineering Contradiction:
Improveantenna cable reliabilityVSAvoiddeployment and rewinding operation
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The antenna system extracts the vulnerable cable rewinding operation by integrating the antenna directly onto the submersible vehicle, eliminating the need for external towing cables and their associated mechanical supports. This removes the source of mechanical breakage while maintaining HF transmission capability through integrated mounting structures.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces a protective dielectric enclosure as an intermediary between the antenna elements and the external environment. This enclosure protects the antenna structure from mechanical damage while allowing electromagnetic transmission, thereby improving reliability without compromising operational ease.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Power

If a wire antenna is used for HF transmission, then data exchange between submersible and land base is enabled, but radio efficiency is low and power transmission is limited to a few watts

Engineering Contradiction:
Improvetransmission powerVSAvoidradio efficiency
Core Design Contradiction:
PowerVSLoss of energy

Solution Approach 1:

The antenna system divides the radiating structure into multiple discrete elements (multiple antennas with different orientations) rather than using a single wire antenna. This segmentation allows each element to be optimized for specific polarization modes and transmission directions, improving overall radio efficiency and power utilization across the HF spectrum.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent employs composite construction combining conductive antenna elements with dielectric enclosures and supporting structures. This composite approach enables the antenna to handle high power transmissions by distributing electrical loads across multiple materials and structures, preventing breakdown that would limit power in simple wire antennas.

Inventive Principle:
Principle #40Composite materials

3Reliability

If the antenna is floating on the surface to enable transmission, then HF emissions are possible, but the antenna is easily visible and mechanically vulnerable

Engineering Contradiction:
Improvemechanical protectionVSAvoidvisibility
Core Design Contradiction:
ReliabilityVSIllumination intensity

Solution Approach 1:

The antenna system merges the transmission function with the submersible's hull or mounting structures, integrating what would be a separate floating antenna into the vehicle itself. This eliminates the need for a visible surface-floating antenna while maintaining transmission capability through the integrated structure.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent uses dielectric enclosures that can be designed as streamlined shells conforming to the submersible's shape. These shells provide mechanical protection and weather resistance while maintaining a low-profile appearance when deployed, reducing visibility compared to traditional floating antenna structures.

Inventive Principle:
Principle #30Flexible shells and thin films

4Device complexity

If traditional wire antennas are used, then simple structure is maintained, but mechanical damage and electrical breakdown occur during operation

Engineering Contradiction:
Improveantenna structure complexityVSAvoidoperational reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The antenna system incorporates protective dielectric enclosures and surge protection circuits before the antenna elements are exposed to operational stresses. These protective measures are built into the structure in advance, cushioning against mechanical damage and electrical breakdown before they can occur during deployment or operation.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The patent employs composite construction combining conductive antenna elements with dielectric enclosures and supporting structures. This composite approach enables the antenna to handle high power transmissions by distributing electrical loads across multiple materials and structures, preventing breakdown that would limit power in simple wire antennas.

Inventive Principle:
Principle #40Composite materials

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 system enhances mechanical and electrical reliability, increases transmission efficiency, and supports high-power communication up to 1kW, reducing ohmic losses and enabling efficient data transmission in the 1.5 to 30 MHz frequency range.

Implementation Method 1

isolated from the water in which it can be immersed by a dielectric enclosure

Methodology Applied
Scientific EffectDielectric isolation: Dielectric

Implementation Method 2

each loop being supplied in opposite phase so that the resultant of the return currents to ground (water) cancels out, thus greatly reducing ohmic losses in the water

Methodology Applied
Scientific EffectElectromagnetic field cancellation: Electromagnetic Induction

Implementation Method 3

The antenna can also include a ferromagnetic core positioned at the center of the two loops, which allows the size of the antenna to be reduced while maintaining good efficiency

Methodology Applied
Scientific EffectFerromagnetism: Ferromagnetism

Data Source

PatentEP3223360B1Dual-loop antenna for an immersed vehicle
Publication Date: 2020.08.26 THALES SA
  • EP3223360B1 patent drawingFigure 1~3
  • EP3223360B1 patent drawingFigure 2
  • EP3223360B1 patent drawingFigure 4A~4B

AI summary

A transmitting and/or receiving antenna (1) intended for equipping a submersible craft, characterized in that it comprises at least the following elements: • A support element (10), • A first loop (2) of a given shape comprising a first end (21) connected to a first point and a second end (22) connected to a common point, • A second loop (3) comprising a first end (31) connected to a second point and a second end (32) connected to the common point, having a shape similar to that of the first loop, • The two loops are symmetrical with respect to the support element (10) and are fed in opposite phase so that the return currents to the common point cancel each other out, • The first and second loops being protected by an enclosure (8). Antenna system comprising an antenna according to the invention.