PCB Shield Structure for Antenna Noise Isolation
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Solution Overview
Problem
Existing electronic devices face challenges in fully contacting shield members with printed boards, leading to potential noise propagation from gaps between them, which can interfere with electronic part operations and wireless communication.
Innovation Solution
The electronic device incorporates a shield member with a protruding portion that extends beyond the printed board and is bent to cover the electronic part, creating a waveguide structure that redirects noise away from the antenna, enhancing isolation by increasing the lengths of the extending and shielding portions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a shield member is arranged to cover electronic parts on a printed board, then noise suppression is improved, but complete contact between the shield member and printed board is difficult to achieve, leading to noise propagation through gaps
Solution Approach 1:
The shield member extends beyond the printed board in the lateral direction and bends downward to contact the side surface of the printed board, transitioning from a single-plane contact to a multi-dimensional contact structure. This allows the shield member to achieve complete contact by utilizing the vertical dimension and side surface of the printed board, eliminating gaps that would otherwise allow noise propagation.
Solution Approach 2:
The contact structure is divided into multiple segments: the main body of the shield member contacts the upper surface of the printed board, while the protruding portion extends laterally and bends to contact the side surface. This segmentation allows each portion to contact different surfaces of the printed board, ensuring complete contact coverage and eliminating gaps for noise propagation.
2Object-affected harmful factors
If the shield member is made to contact the printed board at multiple points, then noise propagation is reduced, but the complexity of the shield member structure increases
Solution Approach 1:
The protruding portion is formed as an integrated extension of the shield member body, combining the shielding function and the contact function into a single continuous structure. This eliminates the need for separate contact elements or fastening mechanisms, reducing structural complexity while achieving complete contact and noise suppression.
Solution Approach 2:
The shield member utilizes the vertical dimension by bending the protruding portion downward to contact the side surface of the printed board. This three-dimensional configuration achieves multiple contact points without requiring additional components or complex assembly mechanisms, as the contact is achieved through the natural geometry of the bent protruding portion.
3Object-affected harmful factors
If the shield member completely contacts the printed board to prevent noise, then noise suppression is improved, but the manufacturing precision requirements increase due to the need for precise positioning and contact
Solution Approach 1:
The protruding portion has a predetermined length and bending radius that are designed to accommodate normal variations in manufacturing and assembly. These parameter tolerances allow the shield member to maintain effective contact with the printed board side surface even when there are minor deviations in positioning, reducing the stringency of manufacturing precision requirements while still achieving complete contact for noise suppression.
Solution Approach 2:
The contact interface is segmented into the protruding portion contacting the side surface and the main body contacting the upper surface. This segmentation provides multiple contact zones that can independently compensate for positioning variations, reducing the overall precision requirements compared to requiring a single precise contact point throughout.
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 suppresses noise propagation, improving isolation between noise-generating electronic parts and antennas, even without screwing the shield member's edge to the printed board, thereby reducing interference and maintaining effective wireless communication.
Implementation Method 1
creating a waveguide structure that redirects noise away from the antenna
Data Source
AI summary
An electronic device includes a printed board having an electronic part mounted on a surface thereof and a shield member arranged so as to be opposite to the surface of the printed board and to cover the electronic part. The shield member has a protruding portion that extends to the outer side beyond one end of the printed board as viewed in top plan, and the protruding portion is bent to the printed board side and has a tip end extending at least to a position opposite to a side face of the printed board.