Wireless Detection of Pressure by Using PDMS Metamaterial Absorber

Pressure sensors are essential across a wide range of application domains, each requiring tailored performance characteristics. In this work, we propose a novel passive and wireless pressure sensor featuring a compact sandwich structure composed of a metasurface (MTS) layer, a compressible polydimethylsiloxane (PDMS) substrate, and a metallic ground plane (GP). When pressure is applied, the PDMS layer undergoes mechanical deformation, leading to both a reduction in thickness and an increase in relative permittivity, which in turn causes a measurable shift in the resonant frequency. A detailed theoretical model based on a pressure-dependent Debye formulation is presented to describe the influence of mechanical compression on the electromagnetic response. The model is validated through full-wave simulations and experimental results. The sensor operates around 22 GHz and can be interrogated wirelessly from a distance of up to 25 cm. It is capable of measuring pressures up to 55 kPa, maintaining stable performance across multiple loading cycles. Thanks to its battery-free operation, compact size, and ease of fabrication, the proposed sensor is well-suited for remote pressure monitoring in environments where conventional wired or active sensors may not be viable.