The research introduces a new small slotted circular biosensor for non-invasively measuring blood glucose levels. The proposed biosensor has an operating frequency of 5.15 GHz. Its overall dimensions are 27 mm × 23 mm × 1.6 mm, with a radius of 8 mm. It uses electromagnetic principles to detect changes in glucose levels without intrusive treatments. Using a cost-effective FR4 dielectric substrate, the biosensor simulates human finger tissue to accurately depict changes in glucose concentration. The results showed that the proposed biosensor can detect changes in glucose concentration by electromagnetic modeling, making it a potential option for continuous glucose monitoring in clinical settings.