IC Rectangular Inductor with Perpendicular Shield Traces
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Solution Overview
Problem
Conventional planar inductors face challenges in achieving a high Q factor due to resistive losses from image currents in substrates and eddy currents in metal shields, which degrade their efficiency and frequency modulation capabilities.
Innovation Solution
A slotted metal shield is used, arranged continuously and symmetrically across the trace, reducing image currents in the substrate while minimizing eddy currents in the shield, and a switchable slotted metal shield can tune the resonant frequency by adjusting the shield's configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a metal shield is added to reduce image currents in the substrate, then the Q factor improves, but eddy currents are generated in the shield causing energy loss
Solution Approach 1:
The continuous metal shield is divided into multiple discrete segments arranged in a pattern. This segmentation interrupts the eddy current paths while maintaining the shielding effect against image currents, thereby reducing eddy current losses without sacrificing the Q factor improvement.
Solution Approach 2:
The shield structure is designed with varying local properties - certain regions have shields while others have gaps, creating a non-uniform distribution. This local variation optimizes the balance between blocking image currents (where shields are present) and minimizing eddy currents (where gaps are present).
2Device complexity
If the metal shield configuration is fixed, then the inductor structure is simple, but the frequency modulation capability is limited
Solution Approach 1:
The shield configuration is made dynamically adjustable through switchable elements that can connect or disconnect different shield segments. This allows the inductor's resonant frequency to be tuned by changing the effective shield geometry, providing frequency modulation capability while maintaining a relatively simple base structure.
Solution Approach 2:
The shield structure serves multiple functions: it provides electromagnetic shielding, enables frequency tuning through switchable configurations, and maintains mechanical support. This multi-functionality reduces the need for separate components and simplifies the overall device architecture.
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 significantly increases the Q factor by over 50% compared to conventional inductors, while allowing for variable frequency modulation by modifying the shield's geometry and switching configurations.
Implementation Method 1
According to Lenz's law magnetic flux 223 causes circular eddy currents in substrate 202 that generate a magnetic flux (not shown) in a direction opposite to that of magnetic flux 223
Implementation Method 2
the associated magnetic field generates additional electromagnetic fields, which will be described in greater detail with reference to FIG. 2
Data Source
AI summary
An inductive device is provided, which includes a substrate, a layer having a plurality of conductive metal traces and a metal shield layer. The conductive trace has an input port, a first portion, a second portion, a third portion and an output port. The metal shield layer is disposed between the substrate and the conductive trace. Each of the plurality of conductive metal traces has a respective length and a respective width. Each of the plurality of conductive metal traces are separated from one another. Each of the plurality of conductive metal traces are disposed perpendicularly with the first portion and the third portion. The metal shield layer provides spaced shield traces substantially perpendicular with the conductive metal traces.