PCB Ground Shielding for Microphone RF Noise in Wearables
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Solution Overview
Problem
Conventional wearable electronic devices with sound components like microphones are vulnerable to radio frequency noise from antenna patterns, leading to compromised microphone performance.
Innovation Solution
The electronic device incorporates a printed circuit board (PCB) structure with a ground surrounding at least a portion of the microphone pad, effectively blocking radio frequency noise and minimizing antenna radiation loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the antenna pattern is disposed near the sound component to provide a compact product, then the device size is reduced, but the microphone becomes vulnerable to radio frequency noise
Solution Approach 1:
A ground structure is introduced as an intermediary element between the antenna pattern and the microphone pad. The ground acts as a mediator that blocks radio frequency noise from reaching the microphone while allowing the antenna and microphone to remain in close proximity for compact device design.
Solution Approach 2:
The ground structure, which occupies space on the PCB, is converted from a potential negative (reducing available space) to a positive element that actively blocks radio frequency noise. The ground serves dual purposes: electrical reference and noise shielding, turning a space-consuming element into a protective feature.
2Reliability
If the ground surrounds the microphone pad to block radio frequency noise, then microphone performance is improved, but the PCB layout complexity increases
Solution Approach 1:
The ground structure is configured with local quality by surrounding only the microphone pad area rather than covering the entire PCB. This localized ground arrangement provides noise protection specifically where needed (around the microphone) while maintaining simplicity in other areas of the PCB layout.
3Length of moving object
If space between antenna and microphone is minimized for compact design, then device miniaturization is achieved, but radio frequency interference increases
Solution Approach 1:
The ground structure serves as an intermediary barrier between the antenna and microphone, enabling them to be positioned close together without direct radio frequency interference. The ground acts as a shielding wall that allows minimal spacing while maintaining signal integrity.
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 enhances microphone performance by reducing radio frequency noise interference and allows for a more compact design by minimizing space between the antenna and microphone.
Implementation Method 1
a ground spaced apart from the first microphone pad and configured to block a signal flowing into the first microphone pad from an external electronic device
Data Source
AI summary
An electronic device includes a microphone module and a printed circuit board on which the microphone module is disposed. The printed circuit board includes a first layer having at least one first microphone pad coupled to the microphone module, a first ground spaced apart from the first microphone pad, and a second microphone pad coupled to the microphone module and connected to the first ground; and a second layer disposed under the first layer and having a second ground opposite to the first microphone pad and at least a part of the first ground.