A Wireless, Passive Multimodal Wearable Sensor With Decoupled Sensing Capabilities

Abstract

ABSTRACT Developing electronic skin (e‐skin) that perceives multi‐stimuli and even exceeds human skin sensing capacity remains a major challenge. Yet existing technologies focused mainly on tactile sensing suffer from poor superimposed multi‐stimuli discrimination, external power dependence, and wired transmission modes. Here, we report an integrated wireless passive wearable sensor based on frequency‐division inductance‐capacitance (LC) resonator array, capable of simultaneously detecting superimposed multi‐stimuli including pressure, odor and humidity, along with decoupling. The system's performance is designed and validated using three‐dimensional full‐wave electromagnetic simulations. Notably, pressure‐sensing with an ultrafast response/recovery (∼5/6 ms) and high sensitivity (6.15 MHz·kPa −1 ) is enabled by a gradient‐modulus trilayer hydrogel incorporating a micro‐pyramidal patterned top‐layer. Furthermore, the sensor demonstrates trace‐level (200 ppb) NO 2 detection without interference from humidity or pressure and exhibits high humidity sensitivity across a wide humidity range (2%–98% RH). Demonstration of this sensor as e‐skin reveals capabilities surpassing previous devices, enabling wireless passive and decoupled detection of small applied mechanical pressure, trace‐level NO 2 , and ambient humidity under complex stimuli conditions, showing high selectivity and minimal cross‐sensitivity. The proposed system introduces a transformative approach, unlocking substantial benefits for a variety of wearable applications.