Vibration Sensitivity Comparison of One-Port and Two-Port MEMS Microphones

Core Concepts

Two-port MEMS microphones exhibit vibration sensitivity inversely proportional to frequency, unlike one-port mics.

Abstract

The content discusses the vibration sensitivity of one-port and two-port MEMS microphones. It starts with an abstract highlighting the interest in two-port microphones for higher directional sensitivity. The introduction explains the difference between one-port and two-port microphones in terms of pressure measurement. The theory section delves into the mechanical models describing vibration sensitivity for both types of microphones. Experimental apparatus and methods are detailed, including validation using a custom shaker setup. Results show that two-port mics have an inversely proportional vibration sensitivity to frequency, while one-port mics are frequency-independent. The conclusion emphasizes that softer sensing elements in microphones increase vibration sensitivity but also sound sensitivity, leading to constant acoustically-referred vibration sensitivity.

Stats

We find that the acoustically-referred vibration sensitivity of two-port MEMS mics is inversely proportional to frequency (𝑆*+/- ∝ 1/𝜔) as opposed to the frequency independent behavior observed in one-port mics.
𝑆*+/-,"/0#' = 9.81𝜌&(𝐿" + 0.5𝐿!) + 9.81𝜌(𝑡(
𝑆*+/-,"/0#' ≈ 9.81𝜌&(𝐿" + 0.5𝐿!)
𝑆*+/- ≡ 𝑆*+ -
⁄ ,!/0#'
𝑆9/*+,!/0#' = 𝑋&))(𝜔)
𝑆9 *+
⁄ (𝜔) ≡ 𝑋&))(𝜔)
𝑆9 -
⁄ (𝜔) = 9.81 𝑚'0' χ(𝜔)
𝑆*+ -
⁄ (𝜔) = 𝑆</-

Quotes

"The presented models accurately predict the vibration sensitivity of one-port and two-port MEMS microphones."
"Microphones with softer sensing elements are more sensitive to vibration, but also equally more sensitive to sound."

Key Insights Distilled From

Vibration Sensitivity of one-port and two-port MEMS microphones

by Francis Doyo... at arxiv.org 03-21-2024

https://arxiv.org/pdf/2403.13643.pdf

Deeper Inquiries

How can the findings on microphone vibration sensitivity impact future designs?

The findings on microphone vibration sensitivity, particularly in the context of one-port and two-port MEMS microphones, can significantly impact future designs. Understanding that two-port mics have an acoustically-referred vibration sensitivity that is inversely proportional to frequency while being independent of the mic's natural frequency opens up new possibilities for directional audio recording applications. Designers can leverage this knowledge to create more robust and accurate microphones for specific use cases where directionality and noise filtering are crucial.

What potential drawbacks might arise from relying on softer sensing elements in microphones?

While using softer sensing elements in microphones may enhance their ability to detect pressure differences between acoustic ports, there are potential drawbacks to consider. Soft sensing elements are more prone to interference from external vibrations, which could lead to increased background noise or unwanted signals being picked up during recordings. Additionally, softer materials may be less durable or stable over time compared to stiffer components, impacting the overall longevity and reliability of the microphone.

How could advancements in MEMS technology influence broader applications beyond audio recording?

Advancements in MEMS (Micro-Electro-Mechanical Systems) technology have the potential to revolutionize various industries beyond audio recording. For example:

In healthcare: Miniaturized MEMS sensors could be used for monitoring vital signs or detecting diseases with high precision.
In automotive: MEMS devices could improve safety features by enabling advanced driver-assistance systems and autonomous driving capabilities.
In aerospace: MEMS sensors could enhance navigation systems and structural health monitoring in aircraft.
In IoT (Internet of Things): MEMS technology can enable smart devices with improved sensor capabilities for environmental monitoring, home automation, and industrial applications.
Overall, advancements in MEMS technology offer a wide range of opportunities for innovation across diverse sectors by providing compact yet powerful solutions for sensing, actuation, and control purposes.