Removable Antenna Module With Static Dissipative Radome

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Solution Overview

Problem

Wireless field devices in hazardous locations face challenges with static electricity when removing or replacing antennas, which can generate sparks due to the accumulation of static charges, and there is a need for a solution that allows for removable antennas while preventing sparking.

Innovation Solution

A wireless field device with a removable antenna module featuring a static dissipative radome made from a thermoplastic material with surface resistivity between 10^5 and 10^9 ohms per square, which dissipates built-up static charge to ground, preventing sparking during antenna attachment and detachment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of repair

If the antenna is made removable for field replacement, then the ease of repair is improved, but the risk of static electricity sparking increases

Engineering Contradiction:
Improveantenna replaceabilityVSAvoidstatic electricity spark risk
Core Design Contradiction:
Ease of repairVSObject-affected harmful factors

Solution Approach 1:

A static dissipative material is introduced as an intermediary component between the antenna and the housing. This material serves as a mediator that safely dissipates static charges through controlled conduction, preventing the accumulation and discharge of static electricity that would otherwise occur during antenna removal or installation. The material has specific electrical properties (surface resistivity between 10^5 to 10^9 ohms per square) that enable it to function as a controlled path for static charge dissipation.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The electrical properties of the radome material are specifically controlled by selecting materials with surface resistivity in the range of 10^5 to 10^9 ohms per square. This parameter change transforms the radome from a conventional insulator into a static dissipative component that actively manages electrostatic charges. The specific resistivity range is chosen to balance between preventing charge accumulation and maintaining radio frequency signal transparency.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If a conventional insulating radome is used, then the antenna protection is improved, but the static charge dissipation capability deteriorates

Engineering Contradiction:
Improveantenna protectionVSAvoidstatic charge accumulation
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The radome material exhibits different functional qualities in different aspects: it maintains its protective and radio-transparent properties while simultaneously providing static dissipation capability. The local quality of the material is optimized to have specific surface resistivity characteristics that enable dual functionality - physical protection of the antenna and controlled dissipation of static charges through the same component structure.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention employs composite or specially formulated thermoplastic materials that combine multiple properties: mechanical strength for protection, radio frequency transparency for signal transmission, and controlled electrical resistivity for static dissipation. These composite materials integrate functions that were traditionally separate (protection and electrical insulation) with the new function of static charge management.

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

Enables safe replacement of antennas in hazardous locations by dissipating static electricity, preventing sparks and ensuring safe operation in flammable or explosive environments.

Implementation Method 1

a radome (60) made from a static dissipative material... which dissipates built-up static charge to ground

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

thermoplastic material with surface resistivity between 10^5 and 10^9 ohms per square, which dissipates built-up static charge

Methodology Applied
Scientific EffectElectrical resistance: Electrical Resistance

Data Source

PatentEP2671283B1Wireless field device or wireless field device adapter with removable antenna module
Publication Date: 2019.10.30 PHOENIX CONTACT GMBH & CO KG
  • EP2671283B1 patent drawingFigure 1~2
  • EP2671283B1 patent drawingFigure 3
  • EP2671283B1 patent drawingFigure 4~6

AI summary

A wireless field device or an adapter for converting a wired field device to a wireless field device includes a housing, a first connector on the housing, and a removable antenna module that includes an antenna, a second connector coupleable and uncoupleable with the first connector, and a radome that houses the antenna and fits on the second connector. The radome is made of a static dissipative material that dissipates static buildup without sparking when coupling or uncoupling the connectors, enabling the antenna to be removed or replaced while the field wireless field device is located in a hazardous (classified) location.