Center-Tapped Inductor Layout for Higher Q With Patterned Shielding

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Solution Overview

Problem

The quality factor value (Q value) of inductors in integrated circuits is affected by eddy currents generated by the substrate, and existing patterned ground shield structures still impact this value negatively.

Innovation Solution

The inductor device incorporates a patterned ground shield structure with first and second traces and first and second center-tapped elements disposed on different layers, with the center-tapped elements passing through the center points of their respective areas, creating a symmetrical structure that cancels coupling between the traces and center-tapped elements, improving the Q value.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a patterned ground shield (PGS) structure is disposed in the inductor, then eddy current suppression is improved, but the quality factor value is still negatively affected

Engineering Contradiction:

Improveeddy current suppressionVSAvoidquality factor value

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The ground shield structure is divided into multiple segmented regions with different patterns (e.g., grid pattern in first region, cross pattern in second region). This segmentation allows each region to independently suppress eddy currents while minimizing their negative impact on the quality factor, resolving the contradiction between eddy current suppression and Q value maintenance.

Inventive Principle:

Principle #1Segmentation

2Productivity

If the inductor operates with smaller electrical elements, then integration density is improved, but quality factor value deteriorates due to eddy currents

Engineering Contradiction:

Improveintegration densityVSAvoidquality factor value

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

Different regions of the ground shield are assigned different patterns and properties tailored to local requirements. The first region uses a grid pattern while the second region uses a cross pattern, allowing each area to optimize both eddy current suppression and quality factor based on its specific position and function within the integrated circuit.

Inventive Principle:

Principle #3Local quality

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 enhances the quality factor value of the inductor device by canceling coupling between traces and center-tapped elements, thereby improving performance.

Implementation Method 1

the first center-tapped element passes through a first center point of the first area... the coupling between the first trace and the first center-tapped element are cancelled

Methodology Applied

Scientific EffectElectromagnetic coupling cancellation: Electromagnetic Induction

Implementation Method 2

If a patterned ground shield (PGS) structure is disposed in the inductor, it is useful to suppress the eddy current occurring in the inductor

Methodology Applied

Scientific EffectEddy current suppression: Eddy Currents

Data Source

PatentUS12538500B2Inductor device

Publication Date: 2026.01.27 REALTEK SEMICON CORP

AI summary

An inductor device includes a pattern ground shield (PGS) structure, a first trace, a second trace, and a first center-tapped element. The first trace is disposed above the pattern ground shield structure, and located in a first area. The second trace is disposed above the pattern ground shield structure, and located in a second area. The first area is adjacent to the second area. The first center-tapped element is disposed above the first trace or below the first trace, and passes through a first center point of the first area.