High-Sensitivity Multifunctional Sensing System Using Spoof Localized Surface Plasmons

We present an advanced multifunctional sensing system based on spoof localized surface plasmons (SLSPs) for high-precision, multi-scenario detection applications, including solid material thicknesses and liquid concentration measurements. The system integrates a multimodal SLSP sensor, ESP32 development board, phase-locked loop (ADF4351), and power detector (AD8362), achieving multiple high-Q factor resonance modes with a benchmark Q factor of 328.6. The SLSP sensing system adopted the resonance-frequency shift method for both solid thickness and liquid concentration sensing, operating effectively across a frequency range from 35 MHz to 3.8 GHz. Experimental validation demonstrated exceptional sensitivity, achieving detection precision of 0.264 GHz/mm for material thickness detection and 2.275×10-4 GHz/(mg·mL-1) for alcohol concentration. Comparative analysis with vector network analyzer results confirmed excellent accuracy and consistency. With its high sensitivity, adaptability, and cost-effectiveness, this SLSP-based sensing system provides a versatile platform for next-generation sensing technologies, addressing the needs of precision industrial material sensing and complex environmental monitoring.