Circuit Substrate Layout for High-Frequency Coil Impedance
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Solution Overview
Problem
Existing circuit substrates with surface-mounted chip-type coil components experience a reduction in impedance in high frequency regions due to increased capacitance between signal lines and ground patterns.
Innovation Solution
The circuit substrate incorporates first and second signal lines, land patterns, and dummy land patterns, where the dummy land patterns are in a floating state, reducing capacitance between land patterns and ground, and ensuring sufficient mounting strength through connections to dummy terminals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If dummy land patterns are connected to ground pattern, then mounting strength is improved, but capacitance between signal line and ground increases causing impedance reduction in high frequency region
Solution Approach 1:
The land patterns are divided into two distinct types: dummy land patterns connected to ground for mechanical strength, and signal land patterns electrically isolated to maintain impedance. This segmentation allows each type to fulfill its specific function without interfering with the other.
Solution Approach 2:
The electrical connection between signal land patterns and ground is extracted/removed, while maintaining the mechanical connection through dummy land patterns. This separation eliminates the harmful capacitance effect while preserving the beneficial mounting strength.
2Strength
If land pattern area is increased to ensure mounting strength, then capacitance between land pattern and ground increases, but impedance in high frequency region is reduced
Solution Approach 1:
The total land pattern area is segmented into dummy land patterns (connected to ground) and signal land patterns (electrically isolated). The dummy patterns provide mechanical strength through their area, while the signal patterns maintain low capacitance through electrical isolation via cuts.
Solution Approach 2:
Cuts are introduced as intermediary elements between the signal land pattern and ground, allowing the signal pattern to maintain its area for mechanical strength while preventing direct electrical connection that would create harmful capacitance.
3Strength
If dummy land patterns are electrically connected to signal lines, then mounting strength is improved, but noise occurrence increases
Solution Approach 1:
The substrate is segmented into distinct electrical zones: ground-connected dummy land patterns for mechanical support, and electrically isolated signal land patterns for signal transmission. This segmentation prevents noise coupling between signal and ground paths.
Solution Approach 2:
The electrical connection between dummy land patterns and signal lines is extracted, eliminating the noise coupling path while maintaining mechanical strength through the dummy patterns' connection to ground.
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 configuration effectively suppresses the reduction in impedance in high frequency regions while maintaining sufficient mounting strength for the coil component, thereby enhancing the circuit substrate's performance.
Implementation Method 1
a capacitance between the signal line and the ground increases to disadvantageously reduce impedance in a high frequency region
Data Source
AI summary
Disclosed herein is a circuit substrate that includes a coil component mounted on the substrate having first and second land patterns and first and second dummy land patterns. The coil component includes a first signal terminal and a first dummy terminal which are provided on the first flange part, a second signal terminal and a second dummy terminal which are provided on the second flange part, and a wire wound around the winding core part and whose one end and other end are connected respectively to the first signal terminal and the second signal terminal. The coil component is mounted on the substrate such that the first and second signal terminals are connected respectively to the first and second land patterns and that the first and second dummy patterns are connected respectively to the first and second dummy land patterns.