Symmetrical Differential Inductor Parasitic Capacitance Reduction
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Solution Overview
Problem
Differential inductors with symmetrical spiral structures experience reduced Q value due to parasitic capacitance generated between adjacent conducting wires, which increases electrical energy consumption.
Innovation Solution
The design of a symmetrical differential inductor with staggered and interwound spiral conducting wires, where the wires are not in contact and are positioned at different heights relative to the substrate, reducing parasitic capacitance and incorporating gain conducting wires to increase cross-sectional area and reduce conductor loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a symmetrical spiral structure is used for differential inductor, then the inductor can be constructed with two ports and opposite electrical properties, but parasitic capacitance is generated between neighboring conducting wires which increases energy consumption and reduces Q value
Solution Approach 1:
The patent applies dimensionality change by transitioning from a planar spiral structure to a three-dimensional interwound structure. The first and second spiral conducting wires are positioned at different heights above the substrate, creating vertical separation. This spatial arrangement in three dimensions reduces the parasitic capacitance between adjacent wires while maintaining the differential inductor functionality.
Solution Approach 2:
The patent introduces asymmetry in the vertical positioning of the conducting wires. The first spiral conducting wire and the second spiral conducting wire are deliberately placed at different heights above the substrate, breaking the symmetrical planar arrangement. This asymmetric vertical positioning reduces the coupling capacitance between adjacent wires while preserving the overall symmetrical differential structure.
2Shape
If conducting wires are placed adjacent to each other in symmetrical spiral structure, then the inductor structure is compact and symmetric, but parasitic capacitance increases reducing Q value
Solution Approach 1:
The patent resolves the contradiction between maintaining symmetrical spiral structure and improving Q value by adding a vertical dimension. The conducting wires are arranged in an interwound three-dimensional configuration at different heights, which preserves the symmetrical differential structure while reducing parasitic capacitance effects that degrade Q value.
Solution Approach 2:
The patent introduces the vertical spacing and air/dielectric medium between the first and second spiral conducting wires as an intermediary element. This spatial separation acts as a mediator that reduces the parasitic capacitance coupling between adjacent wires, thereby improving Q value while maintaining the compact symmetrical structure.
3Volume of moving object
If spiral conducting wires are positioned close to substrate, then the inductor occupies less vertical space, but parasitic capacitance with substrate increases energy consumption
Solution Approach 1:
The patent addresses the contradiction between vertical space occupation and substrate parasitic capacitance by utilizing the vertical dimension strategically. The interwound spiral wires are positioned at optimized heights above the substrate, creating a three-dimensional configuration that balances compactness with reduced capacitive coupling to the substrate, thereby minimizing energy loss.
Data Source
AI summary
A symmetrical differential inductor including a first spiral conducting wire and a second spiral conducting wire is provided. The first spiral conducting wire has a first end and a second end, and the second end whirls in spiral fashion towards a central portion of a spiral structure of the first spiral conducting wire. The second spiral conducting wire and the first spiral conducting wire are interwound with each other and symmetrical to a symmetrical plane. The second spiral conducting wire has a third end and a fourth end, and the fourth end whirls in spiral fashion towards a central portion of a spiral structure of the second spiral conducting wire and is connected to the second end of the first spiral conducting wire. When the first spiral conducting wire and the second spiral conducting wire having the same distance from the substrate are staggered, they extend towards the substrate.