RF Inductor EMI Shielding Using Segmented Conductive Wires
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Solution Overview
Problem
Current EMI shielding solutions for RF modules, such as electrically-conductive metal cans, are impractical due to size constraints in next-generation smaller and thinner RF modules, which require reduced EMI crosstalk between inductors to maintain high Q factors and integrate multiple frequency bands, while existing solutions like grounded metal planes degrade inductor performance.
Innovation Solution
The use of electrically-conductive wires to construct an EMI shield that surrounds and extends over inductors, with predetermined spacing and connection to a common electrical ground structure, to attenuate specific frequency ranges and prevent EMI crosstalk while maintaining high Q factors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If electrically-conductive metal cans are used for EMI shielding, then EMI emissions are reduced, but device size increases and space constraints are violated
Solution Approach 1:
The patent divides the EMI shielding function into segmented electrically-conductive traces routed through multiple PCB layers, replacing the monolithic metal can structure. Each trace segment contributes to the overall shielding effect, enabling distributed EMI protection that integrates within the existing PCB footprint without requiring additional external space.
Solution Approach 2:
The EMI shielding traces are nested within the existing PCB multi-layer structure, utilizing the vertical space between PCB layers. The conductive traces are embedded in the PCB substrate itself, nesting the shielding function within the device's existing structural framework rather than adding external shielding components.
2Object-affected harmful factors
If grounded metal planes are used near inductors for EMI shielding, then EMI crosstalk is reduced, but inductor Q factor deteriorates
Solution Approach 1:
The patent applies different electromagnetic properties to different regions of the PCB by routing electrically-conductive traces selectively in specific layers and patterns. The shielding effect is localized to areas where EMI crosstalk occurs between adjacent inductors, while maintaining optimal magnetic field conditions in the inductor regions through careful trace placement and spacing.
Solution Approach 2:
The electrically-conductive traces act as intermediary elements that provide EMI shielding without directly contacting or being adjacent to the inductors. The traces are routed through intermediate PCB layers, creating a protective electromagnetic barrier that reduces crosstalk while maintaining sufficient distance from the inductors to preserve their Q factors.
3Adaptability or versatility
If multiple frequency bands are integrated into compact RF modules, then functionality increases, but EMI interference between functional blocks increases
Solution Approach 1:
The patent segments the RF module's functional blocks into distinct electromagnetic zones by routing electrically-conductive shielding traces between adjacent functional elements. Each frequency band's circuitry is separated by these conductive barriers, allowing multiple frequency bands to coexist in compact integration while minimizing mutual EMI interference through the segmented shielding approach.
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 solution effectively reduces EMI crosstalk between inductors, enhancing the Q factors and improving EMI shielding efficiency, allowing for compact RF modules with integrated multiple frequency bands and increased package density.
Implementation Method 1
electrically-conductive wires to construct an EMI shield that surrounds and extends over inductors, with predetermined spacing and connection to a common electrical ground structure, to attenuate specific frequency ranges and prevent EMI crosstalk
Data Source
AI summary
Electrically-conductive wires are used to construct an EMI shield between inductors of an RF module that prevents, or at least reduces, EMI crosstalk between the inductors while maintaining high Q factors for the inductors. The EMI shield comprises at least a first set of electrically-conductive wires that at least partially surrounds and extends over at least a first inductor of a pair of inductors. Adjacent wires of the first set are spaced apart from one another by a predetermined distance selected to ensure that the EMI shield attenuates a frequency or frequency range of interest. First and second ends of each of the wires are connected to an electrical ground structure. A length of each wire in between the first and second ends of the respective wire extends above the first inductor and is spaced apart from the first inductor so as not to be in contact with the first inductor.