In this paper. a novel nano sensor structure is proposed. which consists of a metal-insulator-metal waveguide (MIM) with rectangular baffles and a water droplet cavity with rectangular stubs (WDCRS). The WDCRS structure optimizes the sensitivity of a single water droplet cavity and makes the transmission curve clearer and smoother. https://pipingrockers.shop/product-category/burdock-root/