In this paper, by utilizing ring resonator patches (RRPs) within metamaterial structures, a new approach is introduced to showcase the enhancement of light absorption in ultra-narrowband conditions. The utilization of a slit ring resonator enables the excitation of resonance modes characterized by standing wave patterns. The estimation of absorption peak positions can be reliably achieved through the application of the Fabry-Pérot (F–P) cavity model. Attaining absorption with a narrowband spectrum necessitates the simultaneous elimination of reflectance by achieving perfect impedance matching and the suppression of transmission via the metallic layer. The desirable characteristics of ultra narrow bandwidth can be preserved by changing the geometrical parameters of the RRPs. When working as a refractive-index sensor, the RRPs-based metamaterial showcases remarkable sensing capabilities owing to its consistent and reliable enhancement of ultra-narrowband absorption.