Air-coupled dynamic behavior of two-dimensional acoustic sensors

High-performance acoustic devices are essential to a wide array of modern technologies, including high-sensitivity detection electronics and industrial devices. In this context, two-dimensional (2D) materials emerge as highly promising candidates for next-generation acoustic sensing, owing to their exceptional properties. However, existing models, developed primarily for conventional thick membrane materials, are inadequate as they neglect the significant air-coupled effects that dominate ultrathin 2D diaphragms. Here, we develop an equivalent lumped element model (LEM) effectively capturing the air-coupled response of graphene diaphragm down to the monolayer thickness limit. This model demonstrates a high accuracy by a maximum deviation from experiment of approximately 2.8% (~0.24 dB) in the 100-20,000 Hz range. By incorporating electrode radiation impedance, diffracted acoustic pressure, and viscous damping from backplate holes, this model enables precise optimization of 2D sensor performance. More broadly, this LEM framework can be extended to other ultrathin materials, establishing it as a general approach for modeling air-coupled dynamics in nanomaterial-based systems.