Anechoic Structures for EMI Absorption in Communications Modules

Solution Overview

Problem

Communications modules, such as optical transceivers, emit significant electromagnetic interference (EMI) that can interfere with their operation and adjacent components, necessitating a reduction in EMI emission without altering the module's form factor.

Innovation Solution

Incorporation of an anechoic structure within the communications module, comprising a shell with anechoic elements on its inner surfaces, such as truncated pyramids or columns, made from materials like cast zinc metal and nickel, to intercept and scatter EMI, thereby disrupting and dispersing it.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-generated harmful factors

If an anechoic structure is added to reduce EMI emission, then EMI reduction is improved, but device complexity increases

Engineering Contradiction:

ImproveEMI emissionVSAvoidstructure complexity

Core Design Contradiction:

Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The anechoic elements are nested within the existing module housing structure. The truncated pyramid or column-shaped elements are positioned inside the housing, utilizing the internal space without requiring external additions. This nesting approach reduces EMI while avoiding significant increases in overall device complexity.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The anechoic elements are implemented as discrete structural features that can be integrated into the housing shell. These elements function as EMI-absorbing structures while maintaining the integrity of the housing shell, effectively adding EMI reduction capability without substantially altering the form factor.

Inventive Principle:

Principle #30Flexible shells and thin films

2Object-generated harmful factors

If an anechoic structure is added to reduce EMI emission, then EMI reduction is improved, but manufacturing cost increases

Engineering Contradiction:

ImproveEMI emissionVSAvoidmanufacturing cost

Core Design Contradiction:

Object-generated harmful factorsVSEase of manufacture

Solution Approach 1:

The patent specifies particular geometric parameters for the anechoic elements (truncated pyramid or column shapes with specific dimensions) that can be manufactured using standard processes. By defining specific parameter ranges for element size, shape, and material properties, the design enables cost-effective manufacturing while achieving the required EMI reduction performance.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The anechoic elements are made from materials such as cast zinc metal and nickel, which are effective EMI shields. Using these materials in the specific geometric configurations described provides optimal EMI reduction while maintaining manufacturability through established casting and plating processes.

Inventive Principle:

Principle #40Composite materials

3Object-generated harmful factors

If the module housing is altered to accommodate EMI reduction structures, then EMI reduction is improved, but form factor changes

Engineering Contradiction:

ImproveEMI emissionVSAvoidform factor

Core Design Contradiction:

Object-generated harmful factorsVSShape

Solution Approach 1:

The anechoic elements are nested within the existing module housing structure. The truncated pyramid or column-shaped elements are positioned inside the housing, utilizing the internal space without requiring external additions. This nesting approach reduces EMI while avoiding significant increases in overall device complexity.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The anechoic elements are implemented as discrete structural features that can be integrated into the housing shell. These elements function as EMI-absorbing structures while maintaining the integrity of the housing shell, effectively adding EMI reduction capability without substantially altering the form factor.

Inventive Principle:

Principle #30Flexible shells and thin films

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 anechoic structure effectively reduces EMI emission, preventing interference with signal transmission and reception, while maintaining the module's form factor and integrity of data signals.

Implementation Method 1

an anechoic structure positioned on an inner surface of the top shell portion to disrupt and disperse EMI

Methodology Applied

Scientific EffectElectromagnetic absorption: Absorption (EM radiation)

Implementation Method 2

the anechoic elements extend towards the EMI-emitting component(s)... intercept and scatter EMI, thereby disrupting and dispersing it

Methodology Applied

Scientific EffectElectromagnetic scattering: Scattering

Data Source

PatentUS7830296B2Anechoic structures for absorbing electromagnetic interference in a communications module

Publication Date: 2010.11.09 II VI DELAWARE INC

AI summary

A communications module includes an interior configuration designed to intercept, disrupt, and scatter EMI produced by the module during operation. The interior configuration may include an anechoic structure that includes a plurality of anechoic elements positioned proximate EMI-producing components within the module. The anechoic elements may form truncated pyramids, columns having rounded tops, cones, or other shapes. The anechoic elements may be uniform or non-uniform in size, length, or shape and can be arranged in a periodic, non-periodic, or random pattern. In some embodiments, the anechoic elements may include cast zinc metal, Nickel, and/or radiation absorbent material, such as a mixture of iron and carbon. In operation, EMI impinging on the anechoic elements is scattered by their surfaces until absorbed by the elements or other structures of the module, thereby preventing the EMI from exiting the module.