A Microwave Biosensor for Aqueous Glucose Solution with Improved-Sensitivity

This paper proposes a microwave sensor with two tunable status by using active element PIN diodes as on-off switches. In the design, two metamaterial units are utilized and two PIN diodes are placed on each unit, thus, four tunable states (I.e. 0000 state and 1111 state), can be obtained. The distribution of the strongest electric field in 1111 state is larger than that in 0000 state, so the sensitivity in 1111 state is higher than the latter. We mold water-glucose mixture solutions into HFSS simulations with relative dielectric constants as 55.7 and 45.9, which indicates glucose concentration of normal people and diabetic patients, respectively. Simulated results show that the sensor with shorting PIN diodes possesses sensitivity of 2-times higher than that of opening case. The proposed sensor can be widely used in the microwave biosensors field to improve the sensitivity of detection.