Multilayer Inductor with Gradient Coil Thickness
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Solution Overview
Problem
High-frequency inductors used in RF signal transceivers for smartphones face challenges in achieving a high Q factor due to non-uniform current flow and resistance values across different positions in the coil patterns, leading to reduced performance at high frequencies.
Innovation Solution
The inductor design involves stacking insulating layers with coil patterns of varying thicknesses and cross-sectional areas, where coil patterns inwardly have thicker dimensions than those in the outermost positions, optimizing the resistance values and current flow to enhance the Q factor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If coil patterns have uniform thickness across all positions, then manufacturing is simple, but resistance values are non-uniform leading to low Q factor
Solution Approach 1:
The patent applies local quality by varying the thickness of coil patterns at different positions within the inductor body. Specifically, coil patterns at the outermost positions have a first thickness, while coil patterns at inner positions have a second thickness that is greater than the first thickness. This non-uniform thickness distribution compensates for the skin effect and proximity effect at high frequencies, ensuring more uniform current flow and resistance values across different coil patterns, thereby improving the Q factor.
2Reliability
If coil patterns have varying thicknesses to optimize resistance, then Q factor improves, but manufacturing complexity increases
Solution Approach 1:
The patent applies parameter changes by systematically varying the thickness parameter of coil patterns based on their positional parameters. The thickness is changed from a first value at outermost positions to a second value at inner positions, creating a gradient structure that optimizes electrical performance. This controlled parameter variation achieves uniform resistance distribution and high Q factor while maintaining a regular, manufacturable structure.
3Reliability
If coil patterns have larger cross-sectional area inwardly, then resistance values become uniform, but material usage increases
Solution Approach 1:
The patent applies local quality by strategically increasing the cross-sectional area of coil patterns only at specific inner positions where the skin effect and proximity effect cause higher resistance. The outermost coil patterns maintain a smaller cross-sectional area, while inner coil patterns have progressively larger cross-sectional areas. This localized material distribution optimizes resistance uniformity without unnecessarily increasing the total amount of conductive material used throughout the entire inductor.
Data Source
AI summary
An inductor includes: a body having a stack of a plurality of insulating layers, each of which has a coil pattern disposed thereon; and first and second external electrodes disposed on an external surface of the body, wherein the plurality of coil patterns are connected to each other by a coil connection portion and form a coil having both end portions connected to the first and second external electrodes through a coil lead portion, and the plurality of coil patterns are composed of coil patterns disposed in outermost positions and coil patterns disposed inwardly of the coil patterns disposed in the outermost positions of the body, a thickness of at least one of the coil patterns disposed inwardly being thicker than that of the coil patterns disposed in the outermost positions.