Coplanar-to-Via Transmission Line for Lower High-Frequency Return Loss
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Solution Overview
Problem
In existing input/output structures for high-frequency waves, particularly those using a single through via for transmission between the pair of main surfaces of a substrate, return loss increases with higher frequency due to insufficient transmission line capability.
Innovation Solution
A transmission line design that includes a substrate with a first coplanar line and a two-conductor line, where the two-conductor line features a first through via electrically connected to the signal line pattern and passing through the substrate, along with a ground conductor, to reduce return loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single through via is used for high-frequency wave transmission between substrate main surfaces, then the structure is simple, but return loss increases at higher frequencies
Solution Approach 1:
The invention divides the transmission path into two distinct parts: a coplanar line structure on the first main surface for signal transmission, and a two-conductor line structure with through vias for vertical transmission between surfaces. This segmentation allows each part to be optimized for its specific function, with the two-conductor line providing proper transmission line characteristics that reduce return loss compared to a single via structure
Solution Approach 2:
The invention transitions from a single-point via connection to a distributed two-conductor line structure that extends across the substrate thickness. By adding the dimensional extension of conductors through the substrate and along the surface, the transmission path gains proper transmission line characteristics (characteristic impedance control) that reduce reflections and return loss at high frequencies
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 effectively reduces return loss in transmission lines handling high-frequency waves, compared to traditional input/output structures, by utilizing a two-conductor line with a through via and ground conductor for improved signal transmission.
Implementation Method 1
a two-conductor line provided on the substrate, the two-conductor line including: a first through via that is electrically connected with the first signal line pattern and that passes through the substrate from the first main surface to a second main surface of the substrate; and a ground conductor
Data Source
AI summary
To reduce return loss in a transmission line that transmits a high-frequency wave between a pair of main surfaces of a substrate, as compared with the input/output structure included in the filter device disclosed in Patent Literature 1. The transmission line (1) includes: a substrate (10); a coplanar line (20) including a signal line pattern (21) provided on a main surface (11) and a first coplanar pattern (coplanar patterns 22 and 23) provided on the main surface (11); and a two-conductor line (30) including a first through via (31) electrically connected with the signal line pattern (21) and a ground conductor (through vias 32 and 33).