Metamaterial-Inspired Microwave Sensor for Detecting the Concentration of Mixed Phosphate and Nitrate in Water

This is the first report of the construction of a metamaterial-inspired microwave sensor for concentration measurements of aqueous phosphate, nitrate, and mixed phosphate and nitrated solutions. The design of the proposed device is based on a microstrip line (ML) coupled square complementary split-ring resonator (SCSRR), which is squeezed to the narrow width of the slot in the active area. Phosphate, nitrate, and mixed phosphate and nitrate with different liquid sample concentrations inside a cylindrical tube modify the transmission coefficient (S-21) and resonance frequency (f(r)) of the SCSRR. The method utilizes a microwave frequency in the range of 1.0-1.2 GHz with different sample concentrations ranging from 0 to 1 mg/ml. The change of electromagnetic properties can be used to monitor the phosphate, nitrate, and mixed phosphate and nitrate concentrations. Principle component analysis (PCA) is used for sample classification. This chemical sensing concept is potentially useful in biochemistry, medicine, agriculture, and the environment.

Automated summary

This study reports the construction of a metamaterial-inspired microwave sensor for concentration measurements of aqueous phosphate and nitrate solutions. The sensor design is based on a microstrip line coupled square complementary split-ring resonator, with changes in electromagnetic properties used to monitor and classify different sample concentrations. This chemical sensing concept has potential applications in biochemistry, medicine, agriculture, and the environment.