This study presents a novel chipless complementary split-ring resonator (CSRR) loaded substrate integrated waveguide (SIW) tag, coupled with an ultra-wideband coplanar antenna, for real-time monitoring of lubricant evaporation on lubricant-infused surfaces (LISs). The sensor introduces a new method for assessing the stability of the lubricant layer, a critical factor for the efficient operation of these coatings. Its design and functionality have been validated through simulations and measurements of the evaporation rate of two different lubricants with different vapor pressures, demonstrating high sensitivity in detecting lubricant evaporation. This sensor represents a significant advancement in biomaterial development and testing, providing a real-time solution to ensure the effectiveness of lubricant-infused coatings, which is essential for minimizing complications like non-specific adhesion of blood components and bacteria.