Intersecting Metal Strip Ventilation for EMI and Thermal Management

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Solution Overview

Problem

High-performance computing solutions face challenges in thermal management due to limited cooling advancements, particularly in densely packed systems where electromagnetic interference (EMI) constraints restrict airflow, leading to inefficiencies in both cooling and EMI attenuation.

Innovation Solution

A ventilation solution utilizing an EMI containment component with intersecting metal strips that form a Faraday cage behind the faceplate, providing adjustable and customizable airflow openings with an open air ratio greater than 90%, allowing for enhanced cooling while maintaining effective EMI attenuation without the need for machined metal faceplates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If traditional cooling solutions are used in densely packed computing systems, then EMI constraints are satisfied with small openings, but thermal performance deteriorates due to insufficient airflow

Engineering Contradiction:

ImproveEMI attenuationVSAvoidthermal performance

Core Design Contradiction:

Object-affected harmful factorsVSTemperature

Solution Approach 1:

The ventilation opening is segmented into multiple individual openings arranged in a pattern, rather than a single large opening. This segmentation allows the system to maintain adequate EMI shielding (each small opening provides EMI attenuation) while collectively providing sufficient total open area for thermal management

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The ventilation solution applies different characteristics to different regions: the EMI containment component with its specific opening pattern is positioned at the front, while the rear housing and internal structures are designed to complement this arrangement, creating localized EMI shielding zones while maintaining overall airflow pathways

Inventive Principle:

Principle #3Local quality

2Object-affected harmful factors

If machined metal faceplates with ventilation openings are used, then EMI shielding is achieved, but manufacturing cost increases

Engineering Contradiction:

ImproveEMI shieldingVSAvoidmanufacturing cost

Core Design Contradiction:

Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The EMI containment function is segmented from the structural faceplate. Instead of machining EMI openings in an expensive metal faceplate, a separate, simpler EMI containment component with an optimized opening pattern is used, reducing manufacturing complexity and cost

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The EMI containment component is designed as a cost-effective alternative to expensive machined metal faceplates. It provides the necessary EMI shielding function at a lower manufacturing cost, making it economically advantageous for high-volume production

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Productivity

If cooling technology is advanced to match ASIC/FPGA performance improvements, then thermal management improves, but acoustic and thermal impedance limitations prevent further fan technology advancements

Engineering Contradiction:

Improvecooling efficiencyVSAvoidacoustic and thermal impedance

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The ventilation solution optimizes airflow in multiple dimensions by creating a three-dimensional airflow pathway through the device. The EMI containment component with its specific opening pattern, combined with rear ventilation areas, establishes vertical and horizontal airflow channels that maximize cooling efficiency without increasing fan speed or creating acoustic noise

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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

This solution significantly increases airflow and thermal performance, enabling higher power and performance capabilities within a given footprint while ensuring adequate EMI containment, and is cost-effective by eliminating the need for expensive machined metal faceplates.

Implementation Method 1

A ventilation solution utilizing an EMI containment component with intersecting metal strips that form a Faraday cage behind the faceplate

Methodology Applied

Scientific EffectFaraday cage: Faraday Cage

Data Source

PatentUS11140800B2Strip-based ventilation solution for electronic equipment

Publication Date: 2021.10.05 CISCO TECHNOLOGY INC

AI summary

An apparatus suitable for providing ventilation and electromagnetic interference (EMI) containment for a computing device includes a first strip and a second strip. The first strip is sized to span ventilation openings of a computing device covering. The second strip intersects the first strip while also spanning the ventilation openings. Thus, the first strip and the second strip cooperate to define airflow openings within the ventilation openings, the airflow openings being sized to inhibit EMI from exiting the computing device via the ventilation openings.