Investigation of Liquid Dielectric Property Using Circular Split-Ring Resonator Antenna

Simulation study of circular SRR antenna performance as a liquid sensor is presented. The antenna is fed by a coplanar waveguide feed and shows a dual-band response for the 2.4/5.2 GHz range. First, the seawater and blood samples are poured into the central ring of this antenna, and their effects on the antenna return loss and radiation pattern are observed due to change in effective relative permittivity. Further, a thin glass container is placed on the SRR region of this antenna, and the same liquids with large volumes are poured into this container. The sensitivity is estimated from a shift in the resonant frequency for change in effective relative permittivity for each liquid sample. Thus, the circular SRR antenna is realized with the relative sensitivity within the permissible range of 0.156×10^-3 to 1.78×10^-3 for various biomedical applications.