Optical Transceiver Combed Structure EMI Attenuation
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Solution Overview
Problem
Conventional optical transceivers face challenges in reducing electro-magnetic interference (EMI) radiation, particularly at higher frequencies, due to small gaps and misalignment between the face panel and cage, as well as inherent gaps in ground fingers, which are exacerbated by the use of smaller connectors lacking shielding members.
Innovation Solution
The optical transceiver incorporates a combed structure within its housing, featuring a plurality of fins that extend laterally and downwardly, functioning as stubs to attenuate electromagnetic radiation, effectively reducing EMI by increasing the count of fins and optimizing their design to match the operating frequency, including the use of T-shaped fins and dielectric fillers to enhance attenuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If ground fingers are used to fill gaps and stabilize ground, then EMI radiation is reduced, but at higher frequencies (exceeding 10 GHz), small gaps between fingers and misalignment cause EMI radiation to leak
Solution Approach 1:
The housing is segmented into multiple combed fins that extend into the cage, creating multiple grounding contact points. This segmentation allows the structure to maintain effective EMI shielding even when individual fin positions vary due to manufacturing tolerances or misalignment, as the multiple segments provide redundant shielding paths.
Solution Approach 2:
The combed fins extend in a direction perpendicular to the main housing surface, adding a dimensional element that increases the surface area of contact with the cage. This dimensional extension creates overlapping shielding zones that are more tolerant of misalignment and reduce the impact of small gaps between components.
2Volume of moving object
If smaller connectors are used, then device size is reduced, but room for shielding members is eliminated
Solution Approach 1:
The combed fins are integrated directly into the housing structure rather than being separate shielding members attached to the connector. This merging of the shielding function into the existing housing eliminates the need for additional space that would be required for separate shielding components, allowing effective EMI protection even with compact connectors.
Solution Approach 2:
The housing structure serves multiple functions: it provides mechanical support, defines the device envelope, and through the combed fins, provides EMI shielding. This multi-functionality eliminates the need for dedicated shielding members that would require additional space, allowing small connectors to be used without compromising EMI protection.
3Ease of operation
If face panel and cage are misaligned, then assembly ease is improved, but EMI radiation leaks through the gap
Solution Approach 1:
The combed fins provide a dynamic shielding solution where the overlapping fin structures create effective EMI barriers even when the relative position between face panel and cage varies within a range. This dynamic tolerance to position variation allows for easier assembly without requiring precise alignment while maintaining EMI protection.
Solution Approach 2:
The design accepts that some misalignment will occur during assembly and converts this potential harm into a benefit by designing combed fins with overlapping structures that maintain shielding effectiveness across a range of positions. The misalignment that would normally create gaps is compensated for by the extended fin structures that provide continuous shielding coverage.
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 combed structure achieves a significant reduction in EMI radiation, with measured improvements of up to 37% at 10 Gbps and 20.625 GHz, effectively blocking frequency components within the operating range of the optical transceiver, while allowing lower frequency components to propagate, thus enhancing EMI tolerance.
Implementation Method 1
the housing includes a combed structure to attenuate the electromagnetic radiation
Implementation Method 2
the combed structure achieves a significant reduction in EMI radiation, with measured improvements of up to 37% at 10 Gbps and 20.625 GHz, effectively blocking frequency components within the operating range
Data Source
AI summary
An optical transceiver that attenuates the EMI radiation leaked therefrom is disclosed. The optical transceiver includes a top cover and the bottom base to form a cavity into which a TOSA, a ROSA, and a circuit are set. At least one of the top cover and the bottom base provides a combed structure in a rear portion of the optical transceiver, where the combed structure has a plurality of T-shaped fins to attenuate the EMI radiation.