Split-Ring Resonator Sensor for Detecting Water Content in Biological Systems

A new method is proposed to determine the relative water moisture content in biological materials, based on a split-ring resonator (SRR) design. A microwave SRR utilizes capacitive coupling to create a focal point at which a resonance frequency is susceptible to modulation in the presence of a dielectric material. The SRR can transmit signals through a biological system, such as a juvenile tree stem. Then, the transmission data obtained can be used to calculate the relative permittivity of the tree by analyzing a resonance shift in the SRR sensor. This method is non-invasive and reduces measurement time compared to conventional methods. Relative water moisture content is standard practice to determine the amount of available water within a tree relative to its maximum hydration capacity. The results herein show that this sensor design can successfully track water content non-invasively via dielectric material characterization and can prove to be very useful in biological applications such as dehydration prevention.