Liquid Metal Elastomer Foam-Based Sensor Array Using Transmission Line for Continuous Spatial Stress Measurement

Abstract

Stress sensor arrays are widely used in wearable devices, medical health monitoring, and intelligent robotics. However, existing sensor arrays require extensive wiring for each sensor unit, leading to low integration. This article introduces a sensor array based on liquid metal elastomer foam (LMEF) that utilizes a transmission line (TL) for continuous spatial stress measurement with just two wires. Compressing the LMEF changes the dielectric constant above the TL, altering the frequency of the attenuation peak in the transmission coefficient. This allows for continuous spatial stress measurement through just two wires. The mechanism is theoretically investigated via electromagnetic theory and finite-element simulation. Two sensor arrays, a linear sensor array (LSA) and an S-shaped sensor array, are fabricated to evaluate the continuous spatial stress measurement capabilities. Using these sensor arrays, an electronic piano, a digital keyboard, and a gaming control system are demonstrated.