PCB Shielding Structure for RFI Noise Suppression
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Solution Overview
Problem
Power planes on printed circuit boards (PCBs) generate significant radio frequency interference (RFI) noise, which causes interference to LTE, 5G, and Wi-Fi radios, and existing solutions like RF capacitors and metal shields are costly and space-consuming, especially in thin and light form factors.
Innovation Solution
A shielding structure is implemented on the PCB, comprising a metal structure that partially covers the power plane's peripheral region and is electrically grounded through vias to the ground plane, interrupting and blocking unwanted radiation without disturbing the power plane's operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If RF capacitors are added to reduce RFI noise, then radio frequency interference is reduced, but device complexity and cost increase
Solution Approach 1:
The patent extracts the RFI shielding function from complex solutions (multiple capacitors, metal shields) and implements it through a simple grounded metal structure integrated into the PCB layers. This removes the need for additional RF capacitors while maintaining RFI reduction effectiveness.
Solution Approach 2:
The grounded metal structure serves multiple functions: it provides RFI shielding, maintains electrical connection to ground plane, and integrates with the PCB existing structure. This multi-functionality eliminates the need for separate RFI reduction components.
2Object-affected harmful factors
If metal shield enclosures are added to cover exposed power shapes, then RFI radiation is blocked, but device volume and weight increase
Solution Approach 1:
Instead of adding a three-dimensional metal shield enclosure, the patent uses a two-dimensional grounded metal structure integrated into the PCB layers. This dimensional reduction maintains RFI blocking effectiveness while significantly reducing device volume.
Solution Approach 2:
The RFI shielding structure is nested within the existing PCB layer structure, with metal elements integrated into the circuit board layers and grounded through vias. This nesting approach eliminates the need for separate external shield enclosures.
3Object-affected harmful factors
If EMI absorbers are added to reduce radiation, then electromagnetic interference is reduced, but device height and complexity increase
Solution Approach 1:
The patent removes the need for EMI absorbers by implementing a grounded metal structure that passively blocks and redirects electromagnetic interference. This extraction of the shielding function from thickness-consuming absorbers reduces device height.
Solution Approach 2:
Instead of using EMI absorbers that rely on material properties and thickness, the patent uses a grounded metal structure that relies on electromagnetic field interaction and electrical grounding. This substitution achieves the same RFI reduction with minimal height consumption.
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 RFI noise without the need for additional RF capacitors or EMI absorbers, maintaining the power plane's functionality while minimizing unwanted radiation, thus enhancing the performance of wireless devices.
Implementation Method 1
a shielding structure partially covering the power plane, the shielding structure including a metal structure covering a peripheral area of the first main surface
Implementation Method 2
a plurality of vias electrically and mechanically coupling the metal structure to the ground plane
Data Source
AI summary
A printed circuit board includes a ground plane, a power plane having a first main surface and a second main surface opposite to the first main surface, wherein the second main surface faces the ground plane and a shielding structure partially covering the power plane. The shielding structure includes a metal structure covering a peripheral area of the first main surface from a direction facing the first main surface and a plurality of vias electrically and mechanically coupling the metal structure to the ground plane.