Experimental investigation of whispering-gallery-mode dielectric resonators for biological material characterization

A whispering-gallery-mode (WGM) dielectric resonator is proposed as a biological material sensor. This paper investigates the feasibility of this device in sensing small variations within the dielectric properties of the material regardless its shape, volume or position. The geometry of the resonator is slightly modified to fit liquid materials testing. This solution can be promising for sensing human-body tissues or liquids such as blood or urine. The experimental setup is successfully utilized to detect the dielectric constant of a water droplet as a liquid sample and another bulky material of an arbitrary shape. The material measurements are performed over the X-band where accurate results are obtained.