Multilayer Substrate Inductor Shielding
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Solution Overview
Problem
In multilayer substrate modules for communication devices, the proximity of inductors to ground conductors leads to magnetic field interactions, causing eddy currents and degradation of the Q value and insertion loss (IL) improvement effects, especially in low-profile designs.
Innovation Solution
The multilayer substrate module design positions the inductor such that it is not superposed with the ground conductor, either by using separate ground conductors on either side of the inductor or providing openings in the ground conductor to prevent magnetic field interaction, thereby reducing eddy currents and enhancing the Q value and IL improvement effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the inductor is positioned close to the ground conductor to reduce profile height, then the multilayer substrate module achieves a low-profile structure, but eddy currents are generated in the ground conductor causing Q value degradation
Solution Approach 1:
The patent positions the inductor between two ground conductors (first ground conductor and second ground conductor) on opposite sides of the inductor layer. This spatial arrangement in the vertical dimension allows the inductor to maintain proximity to ground conductors for shielding while preventing direct facing that would cause eddy currents, thus resolving the contradiction between low profile height and Q value maintenance.
2Loss of energy
If the inductor is positioned close to the ground conductor to improve impedance matching, then insertion loss is reduced, but magnetic field interactions cause eddy currents that degrade Q value
Solution Approach 1:
The patent introduces a dielectric layer between the inductor and the ground conductors. This dielectric layer acts as an intermediary that allows the inductor to be positioned close to ground conductors for impedance matching and shielding benefits while preventing direct magnetic field coupling that would generate eddy currents, thus maintaining both low insertion loss and high Q value.
3Device complexity
If the inductor is positioned close to the ground conductor to achieve compact design, then the multilayer substrate module profile decreases, but capacitance is generated causing impedance mismatching
Solution Approach 1:
The patent arranges the inductor between two ground conductors on opposite sides in the vertical dimension, creating a compact profile while the dielectric layer prevents unwanted capacitance formation. This dimensional arrangement allows the inductor to be surrounded by ground conductors for shielding without creating parasitic capacitance that would cause impedance mismatching.
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 effectively improves the Q value of the inductor and achieves a significant IL improvement effect while maintaining the existing conductor pattern design, reducing manufacturing costs and preventing degradation of isolation characteristics.
Implementation Method 1
a magnetic field is generated by the inductor when a signal is transmitted through the inductor
Implementation Method 2
an eddy current is generated in the portion of the ground conductor that faces the inductor
Data Source
AI summary
A multilayer substrate module includes a multilayer circuit substrate, a mounting land, and an input/output terminal. Inside the multilayer circuit substrate, a wiring line that connects the mounting land and the input/output terminal to each other, an inductor that defines a portion of the wiring line, a first ground conductor that is positioned on the one main surface side of the inductor, and a second ground conductor that is positioned on the other main surface side of the inductor are defined by conductor patterns. The area where inductor is located is not superposed with the area where the second ground conductor is located, when the one main surface or the other main surface of the multilayer circuit substrate is viewed in plan, the second ground conductor being closer to the layer where the inductor is located than the first ground conductor is.