Manhole Cover Antenna Layout for Reliable Underground Signal Transmission

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Solution Overview

Problem

Manhole covers made of cast iron, often reinforced with concrete and electrically grounded, pose significant challenges for transmitting radio signals from inside a manhole to the outside due to electromagnetic interference and physical durability issues.

Innovation Solution

A remote sensing system with an internal antenna unit secured to the lower surface of a manhole cover and an external antenna unit placed within an aperture, coupled via connector cables or a repeater unit, using LoRaWAN technology for effective signal transmission while withstanding harsh conditions and electromagnetic interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a manhole cover is made of cast iron and electrically grounded, then the structural strength and grounding are improved, but the transmission of radio signals deteriorates due to electromagnetic interference

Engineering Contradiction:
Improvestructural strengthVSAvoidsignal transmission reliability
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The antenna system is segmented into two separate units: an internal antenna unit secured to the lower surface of the manhole cover and an external antenna unit placed within the aperture. This segmentation allows the internal antenna to operate close to the signal source while the external antenna transmits signals to the outside, bypassing the electromagnetic interference caused by the grounded cast iron cover.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The aperture in the manhole cover serves as an intermediary structure that allows the external antenna unit to be positioned within it, creating a transmission path through the cover without compromising the cover's structural integrity or grounding properties. The coupling means electrically connect the two antenna units through this intermediary structure.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If an external antenna is exposed on the upper surface of the manhole cover, then signal transmission to the outside is improved, but the protection against harsh usage conditions deteriorates

Engineering Contradiction:
Improvesignal transmission reliabilityVSAvoidprotection against harsh usage conditions
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The external antenna unit is nested within the aperture structure of the manhole cover, which provides physical protection against harsh usage conditions such as vehicle traffic and environmental exposure. The aperture acts as a protective enclosure that shields the antenna while still allowing it to function effectively for signal transmission.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Reliability

If an aperture is created in the manhole cover for the external antenna, then signal transmission is improved, but the structural integrity deteriorates

Engineering Contradiction:
Improvesignal transmission reliabilityVSAvoidstructural integrity
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The aperture is designed with specific local characteristics - it is positioned and sized to provide adequate signal transmission while minimizing impact on the overall structural integrity of the manhole cover. The aperture's location and dimensions are optimized to maintain strength in critical areas while enabling antenna functionality.

Inventive Principle:
Principle #3Local quality

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 system enables reliable and durable transmission of radio signals from inside a manhole to the outside, effectively protecting the external antenna and maintaining signal integrity despite harsh usage conditions and electromagnetic interference.

Implementation Method 1

an internal antenna unit (3) secured to the lower surface (6) of the manhole cover body (2a)... a transmitter unit (10) configured to transmit radio signals to the internal antenna unit (3)

Methodology Applied
Scientific EffectRadio signal reception: Electromagnetic Induction

Implementation Method 2

coupling means (5) electrically coupling the internal antenna unit (3) to the external antenna unit (4)... the coupling means transmit radio signals received by the internal antenna unit (3) to the external antenna unit (4)

Methodology Applied
Scientific EffectRadio signal transmission: Electromagnetic Induction

Data Source

PatentEP3651267B1Cover element with transmitter system
Publication Date: 2023.09.13 REMONDIS AQUA IND GMBH & CO KG
  • EP3651267B1 patent drawingFigure 1~2
  • EP3651267B1 patent drawingFigure 3~4
  • EP3651267B1 patent drawingFigure 5~6

AI summary

The invention relates to a remote sensing system comprising an internal antenna unit securable to the lower surface of a cover element, especially a manhole cover, an external antenna unit for transmitting a signal to a communication device outside of the upper surface of the cover element, especially the manhole cover, and coupling means electrically coupling the internal antenna unit to the external antenna unit. The invention also relates to a cover element, especially a manhole cover, with an aperture comprising an internal antenna unit secured to the lower surface and an external antenna unit placed within/inside the aperture and coupling means electrically coupling the internal antenna unit to the external antenna unit. The invention further also relates to a transmitter system comprising a cover element, especially a manhole cover, with an aperture, an internal antenna unit secured to the lower surface of the manhole cover body, an external antenna unit placed within/inside the aperture, coupling means electrically coupling the internal antenna unit to the external antenna unit, and finally a transmitter unit configured to transmit radio signals to the internal antenna unit.