High-Frequency Board Recess for Impedance Control
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Solution Overview
Problem
Existing high-frequency boards experience impedance reduction and significant signal loss when trying to transmit high-frequency signals due to the close proximity of line conductors, which decreases their transmission efficiency.
Innovation Solution
A high-frequency board design featuring an insulating substrate with a recess between the first and second line conductors, reducing the dielectric constant in that area and increasing electrostatic capacity, allowing for adjustable characteristic impedance and improved high-frequency signal transmission characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the first and second line conductors are placed close to each other on the insulating substrate, then the board area is reduced, but the characteristic impedance decreases and signal loss increases
Solution Approach 1:
The patent applies local quality by creating a recess portion between the first and second line conductors that extends from the front surface toward the rear surface of the insulating substrate. This recess portion has a different dielectric constant than the surrounding insulating substrate, creating a localized region with modified electromagnetic properties. The recess portion may be filled with a material having a lower dielectric constant (such as air or a low-k material), which increases the characteristic impedance between the conductors without requiring them to be spaced further apart, thus maintaining compact board area while improving signal transmission quality.
2Reliability
If the line conductors are spaced further apart, then the characteristic impedance increases, but the board area increases
Solution Approach 1:
The patent applies the dimensionality change principle by transitioning from a two-dimensional solution (spacing conductors further apart on the surface) to a three-dimensional solution (creating a recess portion that extends vertically from the front surface toward the rear surface). The recess portion's depth into the substrate allows it to affect the electromagnetic field distribution between the conductors without increasing the horizontal distance between them. This vertical dimension enables impedance control while maintaining compact board area.
3Reliability
If a recess portion with lower dielectric constant is created between the line conductors, then the characteristic impedance increases and signal loss decreases, but the manufacturing complexity increases
Solution Approach 1:
The patent applies the porous materials principle by utilizing the recess portion as a void or low-density region within the insulating substrate. The recess portion may be filled with air, vacuum, or a low-k dielectric material, creating a porous or heterogeneous structure that has a lower average dielectric constant than the solid insulating substrate. This approach increases the characteristic impedance and reduces signal loss while the recess portion can be formed using standard semiconductor fabrication techniques such as etching, keeping manufacturing complexity manageable.
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 design effectively maintains or increases the characteristic impedance, reducing signal loss and improving high-frequency signal transmission efficiency by creating a space between the line conductors, thus enhancing the board's frequency characteristics.
Implementation Method 1
The recess is located between the first line conductor and the second line conductor, and has a lower dielectric constant than the insulating substrate
Data Source
AI summary
A high-frequency board includes an insulating substrate, a first line conductor, and a second line conductor. The insulating substrate has an upper surface with a recess. The first line conductor is located on the upper surface of the insulating substrate. The second line conductor is located on the upper surface of the insulating substrate and extends parallel to the first line conductor with a space from the first line conductor as viewed from above. The recess is located between the first line conductor and the second line conductor, and has a lower dielectric constant than the insulating substrate.