A Microwave Dielectric Biosensor Based on Suspended Distributed MEMS Transmission Lines

Design and characterization of a miniature microwave dielectric biosensor based on distributed microelectromechanical systems (MEMS) transmission lines (DMTL) is reported in this paper. The biosensor has been realized by bonding the DMTL device with an acrylic fluidic channel. In order to demonstrate the sensing mechanism, the sensor is used to detect the small variation of the concentration of aqueous glucose solutions by measuring the electromagnetic resonant frequency shift of the device. It is observed from the results that the second notch of the reflection coefficient (S₁₁) varies from 7.66 to 7.93 GHz and the third notch of the reflection coefficient varies from 15.81 to 15.24 GHz when the concentration of the glucose solution ranges from 0 to 347 mg/ml, which indicates that higher order notches have higher sensitivities if looking at the absolute change in frequency.