Multilayer Coil Component Stray Capacitance Reduction
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Solution Overview
Problem
Existing multilayer inductors lack satisfactory radio frequency characteristics for operation above 20 GHz due to excessive stray capacitance caused by electrode design, which is not optimized for high-frequency applications.
Innovation Solution
A multilayer coil component with a coil structure where the first and second outer electrodes cover specific parts of the end faces and major faces, respectively, while extending to cover parts of the lateral faces, with a coil length between 85% and 94% of the multilayer body length, reducing stray capacitance and enhancing radio frequency performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the electrode covers the entirety of both end faces of the multilayer inductor, then the ease of mounting is improved, but the stray capacitance increases causing resonance and deteriorating radio frequency characteristics
Solution Approach 1:
The electrode is designed to cover only specific regions of the end faces rather than the entire surface. The electrode pattern is localized to areas that provide sufficient mounting ease while avoiding regions that would generate excessive stray capacitance, thus resolving the contradiction between ease of mounting and radio frequency performance.
2Ease of operation
If the electrode thickness L6 is increased, then the ease of mounting is improved, but the stray capacitance increases causing resonance and deteriorating radio frequency characteristics
Solution Approach 1:
The electrode thickness parameter is optimized to a specific range that balances mounting ease with radio frequency performance. By carefully controlling the thickness parameter within defined limits, the design achieves sufficient mechanical stability for mounting while preventing excessive stray capacitance that would cause resonance at high frequencies.
3Reliability
If the coil length is increased, then the inductance increases, but the radio frequency characteristics deteriorate due to increased stray capacitance
Solution Approach 1:
The coil structure is designed with specific local characteristics including optimized turn spacing and winding density in different regions. This local optimization allows the coil to achieve the required inductance value while minimizing the stray capacitance between adjacent turns and between the coil and electrodes, thereby maintaining good radio frequency characteristics.
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 achieves improved radio frequency characteristics, with transmission coefficients S21 at 40 GHz and 50 GHz ranging from −1 dB to 0 dB, suitable for high-frequency applications such as optical communication circuits.
Implementation Method 1
a coil part embedded in the element body... The winding axis of the coil part and the electrodes intersect each other
Implementation Method 2
This results in a large stray capacitance due to the electrode. This stray capacitance (capacitance component) causes resonance with the inductance component
Data Source
AI summary
A multilayer coil component includes a multilayer body formed by stacking a plurality of insulating layers and including a coil built therein, and first and second outer electrodes electrically connected to the coil. The coil is formed by electrically connecting a plurality of coil conductors stacked together with the insulating layers. The multilayer coil component further includes, inside the multilayer body, first and second connecting conductors. The first connecting conductor connects between a portion of the first outer electrode covering the first end face, and a coil conductor facing the portion. The second connecting conductor connects between a portion of the second outer electrode covering the second end face, and a coil conductor facing the portion. With respect to the length direction, the coil has a length from about 85.0% to about 94.0% of the length of the multilayer body.