Multichannel RF Feedthroughs Double-Side Trace Routing
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Solution Overview
Problem
High-speed optical transceiver modules face challenges in meeting Multi-Source Agreements (MSA) requirements for RF feedthroughs in terms of package dimensions, bandwidth, and channel density due to problematic interconnections within optical subassemblies.
Innovation Solution
The development of multichannel RF feedthroughs with double-side accessibility, featuring internal and external portions with sets of traces and vias that connect them, allowing for reduced packaging width while maintaining channel capacity, and employing a balanced via distribution for improved RF performance across channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If single-side accessibility RF feedthrough design is used, then manufacturing is simpler, but packaging width is larger and channel density is lower
Solution Approach 1:
The patent transitions from single-side accessibility to double-side accessibility, utilizing both top and bottom surfaces of the feedthrough substrate. This dimensional change allows traces to be routed on both sides, effectively doubling the available channel capacity within the same packaging footprint, thereby reducing packaging width while maintaining manufacturing feasibility
Solution Approach 2:
The feedthrough design segments the trace routing into multiple layers and sides (top and bottom surfaces). By dividing the channel distribution across both surfaces and utilizing via connections to link corresponding traces, the patent achieves higher channel density without proportionally increasing packaging width
2Area of stationary object
If packaging width is reduced to meet MSA requirements, then device size is smaller, but RF performance homogeneity across channels deteriorates
Solution Approach 1:
The patent employs asymmetric via placement and trace routing configurations to compensate for the reduced packaging width. By strategically positioning vias and adjusting trace lengths on different sides of the substrate, the design maintains balanced RF performance across all channels despite the compact form factor
Solution Approach 2:
The patent adjusts critical design parameters including via diameter, trace width, trace spacing, and via distribution patterns to optimize RF performance. By carefully controlling these parameters, the design achieves homogeneous RF characteristics across channels while maintaining reduced packaging width
3Productivity
If channel density is increased to support higher data rates, then bandwidth capacity is improved, but manufacturing complexity increases
Solution Approach 1:
The via structures serve multiple functions: they connect traces between sides, provide grounding references, and act as shielding elements. This multi-functionality allows the design to achieve high channel density without proportionally increasing manufacturing complexity, as the same via fabrication process accomplishes multiple objectives
Solution Approach 2:
The patent combines signal traces and ground references into integrated trace patterns on both sides of the substrate. By merging these elements into unified routing schemes and using shared via structures for multiple channels, the design achieves high bandwidth capacity while controlling manufacturing complexity through standardized fabrication processes
Data Source
AI summary
Multichannel RF Feedthroughs. In some examples, a multichannel RF feedthrough includes an internal portion and an external portion. The internal portion includes a top surface on which first and second sets of traces are formed. Each set of traces is configured as an electrical communication channel to carry electrical data signals. The external portion includes a bottom surface on which the first set of traces is formed and a top surface on which the second set of traces is formed. A set of vias connects the first set of traces between the top surface of the internal portion and the bottom surface of the external portion.