Converter Design Eliminating Open Stubs in Laminated Substrates
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Solution Overview
Problem
The existing coaxial-strip line converters experience increased transmission losses and reliability issues due to open stubs and differential thermal expansion between dielectric substrates and via materials, especially in laminated structures with a high number of layers and large aspect ratios.
Innovation Solution
A converter design that eliminates open stubs by providing a via only in one dielectric substrate, reducing the via's aspect ratio and using an adhesive layer to bond substrates, which also simplifies manufacturing and reduces costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a through-hole penetrating the laminated structure is provided with a conductive via to couple the signal line and coaxial connector, then the signal transmission is enabled, but the open stub at the uncoupled end increases inconsistent losses
Solution Approach 1:
The invention extracts and eliminates the harmful open stub portion from the via structure by making the via extend only through the first dielectric substrate and not penetrating the second dielectric substrate, thereby removing the source of inconsistent losses while maintaining signal transmission functionality
Solution Approach 2:
The invention segments the via structure into two distinct parts: a conductive via in the first dielectric substrate that provides signal transmission, and a non-conductive via in the second dielectric substrate that avoids creating an open stub, thereby resolving the contradiction between signal coupling and loss reduction
2Adaptability or versatility
If the number of laminated layers is increased to achieve higher performance, then the antenna functionality is improved, but the aspect ratio of the via increases causing via breakage due to thermal expansion differences
Solution Approach 1:
The invention divides the via structure across different substrate layers, with the conductive via confined to the first dielectric substrate and the through-hole continuing through the second dielectric substrate without being fully conductive. This segmentation reduces the effective conductive path length and aspect ratio, preventing via breakage while allowing increased laminated layers for improved antenna performance
Solution Approach 2:
The invention applies different properties to different regions: the first dielectric substrate contains a conductive via for signal transmission, while the second dielectric substrate contains only a non-conductive through-hole. This local differentiation reduces thermal stress concentration and prevents via breakage in high-layer configurations
3Reliability
If the build-up construction method is used to generate multi-layered substrate with partial via, then the open stub problem is prevented, but the manufacturing difficulty and cost increase when using PTFE as dielectric substrate
Solution Approach 1:
The invention segments the via formation process into two stages: first forming a conductive via in the first dielectric substrate using conventional methods, then forming a non-conductive through-hole in the second dielectric substrate. This segmentation avoids the need for complex build-up construction methods while preventing open stub formation, thereby improving manufacturability
Solution Approach 2:
Instead of creating a conductive via through the entire laminated structure (which causes open stub problems) or using complex build-up methods (which increase cost), the invention inverts the approach by making the via non-conductive in the second substrate layer, thereby eliminating the open stub issue while simplifying manufacturing
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 design prevents inconsistent losses and degradation of via reliability, maintaining signal integrity while reducing manufacturing complexity and costs, even with increased laminated layers.
Implementation Method 1
a second dielectric substrate provided above the first dielectric substrate through an adhesive layer
Data Source
AI summary
According to one embodiment, a converter includes a first dielectric substrate; a second dielectric substrate provided above the first dielectric substrate through a first adhesive layer; a first signal line provided between the first dielectric substrate and the second dielectric substrate; a first via that penetrates the first dielectric substrate and is coupled to the first signal line on an upper side of the first via; and a first conductor plate provided at least one of below the first dielectric substrate and above the second dielectric substrate.