Conductive Adhesive for Space Radar Antenna Grounding

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Solution Overview

Problem

Space radar antennas face challenges in grounding metal patches to prevent uncontrolled electrostatic discharges due to the accumulation of static charges from the space environment, with existing electrically conductive adhesives causing high RF loss and potential circuit degradation.

Innovation Solution

An electrically conductive adhesive comprising an organic polymer resin and a doped polyaniline electrically conductive polymer, with a resistance range of 10^4 to less than 10^9 ohms, is used to ground floating metal components, allowing for controlled discharge of static charges without significant RF signal absorption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If solid conductive fillers (carbon powder, graphite, or electrically conductive ceramic or metals) are used in the adhesive, then the adhesive can ground metal patches and bleed off static charges, but the fillers absorb RF signals resulting in high RF return and insertion loss

Engineering Contradiction:
Improvegrounding capabilityVSAvoidRF signal loss
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The invention changes the electrical conductivity parameter of the adhesive by using a conductive polymer matrix instead of solid conductive fillers. The conductive polymer provides a different conductivity mechanism that does not involve RF signal absorption, thereby reducing RF loss while maintaining grounding capability. The conductivity is tuned through polymer selection and formulation rather than filler concentration.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention replaces the mechanical filler-based conductivity system with a polymer-based electrical conductivity system. Instead of relying on physical contact networks of solid fillers that absorb RF energy, the conductive polymer provides electron delocalization pathways for static charge dissipation without interfering with RF signal transmission.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If the electrical conductivity of the adhesive is increased to improve grounding, then static charges can be bled off more effectively, but excessive current may flow between metal patches leading to circuit degradation or shorting

Engineering Contradiction:
Improvestatic charge dissipationVSAvoidexcessive current damage
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention applies partial conductivity to the adhesive - enough to dissipate static charges safely but not so much as to create excessive current pathways. The conductive polymer provides controlled conductivity that exceeds insulating levels but remains below the threshold for harmful current flow, achieving the optimal intermediate state for space antenna applications.

Inventive Principle:
Principle #16Partial or excessive action

3Reliability

If metal pins are used to ground each metal element, then each patch can be reliably grounded, but the design complexity increases and it becomes impractical for lightweight foam tiles

Engineering Contradiction:
Improvegrounding reliabilityVSAvoidantenna design complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention merges the grounding function with the adhesive bonding function. The conductive polymer adhesive simultaneously bonds the foam tile to the substrate and provides the grounding pathway for static charge dissipation, eliminating the need for separate metal pin grounding structures and simplifying the overall antenna design.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The conductive polymer adhesive serves multiple functions: it acts as the bonding adhesive for structural attachment, provides electrical conductivity for static charge dissipation, and maintains low RF loss for signal integrity. This multi-functionality replaces the need for separate grounding components and reduces overall system complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 adhesive provides effective grounding with low RF loss, preventing uncontrolled discharges and maintaining antenna performance, while its resistance remains within a suitable range across varying temperatures.

Implementation Method 1

an electrically conductive polymer, wherein the electrically conductive adhesive has an electrical resistance of from about 10 4 to less than 10 9 ohms

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP2157148B1Low RF loss static dissipative adhesive
Publication Date: 2020.10.07 THE BOEING CO
  • EP2157148B1 patent drawingFigure 1~2
  • EP2157148B1 patent drawingFigure 3
  • EP2157148B1 patent drawing

AI summary

The present disclosure is generally directed to electrically conductive adhesives. More particularly, the disclosure is directed to electrically conductive adhesives comprising an organic polymer resin and an electrically conductive polymer. Advantageously, the electrically conductive adhesives have low RF loss, and are thus suitable for use in a space radar antenna and in other antenna applications where antenna components are in the RF field of view.