Notched Coplanar Ground Patterns for Impedance Matching
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional coplanar lines with a backside ground experience degradation in reflection characteristics from low-frequency to high-frequency waves, requiring excessively short contact distances and close arrangement of surface ground contacts to the signal line, which complicates manufacturing and increases costs.
Innovation Solution
A coplanar line design with a dielectric substrate, a signal line, first and second surface ground patterns, and a backside ground pattern, where contacts penetrate the substrate to connect these patterns, with notches of specific shapes on the surface ground patterns to maintain impedance matching across frequencies, allowing for increased contact spacing and improved reflection characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If contact distances are increased to simplify manufacturing, then ease of manufacture improves, but reflection characteristics deteriorate
Solution Approach 1:
The surface ground patterns are segmented by introducing notches that divide the continuous ground pattern into multiple sections. This segmentation allows the ground pattern to maintain its electrical connectivity function while reducing the effective length of current paths, thereby improving reflection characteristics without requiring excessively short contact distances.
Solution Approach 2:
Notches are strategically introduced at specific locations in the surface ground patterns, creating local variations in the ground structure. These localized modifications improve impedance matching and reflection characteristics at critical points without affecting the overall structure, allowing for increased contact spacing while maintaining performance.
2Reliability
If surface ground contacts are arranged closer to the signal line to improve reflection characteristics, then reflection characteristics improve, but device complexity increases
Solution Approach 1:
The continuous surface ground pattern is divided into segmented sections by notches, allowing the ground pattern to maintain effective electrical connection with the signal line while reducing the overall complexity of contact arrangement. The segmentation provides multiple connection points without requiring excessively close spacing.
Solution Approach 2:
Notches are positioned at specific locations in the surface ground patterns to create local impedance matching improvements. This localized approach enhances reflection characteristics without requiring a uniform reduction in all contact distances, thereby simplifying the overall device structure.
3Ease of manufacture
If contact distances are increased, then manufacturing complexity reduces, but strength reduction occurs
Solution Approach 1:
The notched ground patterns create multiple distributed connection points between the surface grounds and backside ground, replacing reliance on a few long contacts with many shorter effective connection paths. This segmentation maintains structural strength while allowing increased physical spacing between contacts.
Data Source
AI summary
A high-frequency transmission line includes: a dielectric substrate; a signal line formed on one surface of the dielectric substrate; a first and a second surface ground patterns formed so as to sandwich the signal line at a given distance from the signal line on the surface of the dielectric substrate; a backside surface ground pattern formed on another surface of the dielectric substrate; and a plurality of contacts penetrating the dielectric substrate for connecting the first and the second surface ground pattern to the backside surface ground pattern. In a given frequency range, the sum of the shortest distance from any point of the first and the second surface ground patterns to the nearest contact and the thickness of the dielectric substrate is shorter than ¼ of the effective wavelength of a transmission signal converted in the effective permittivity of the dielectric substrate.