High performance design for detecting NaI–water concentrations using a two-dimensional phononic crystal biosensor

Abstract In this research, the sensing NaI (sodium iodide)–water concentration is achieved by using a local resonant two-dimensional solid–liquid phononic crystal (PnC) design. The sensor design consists of a square arrangement from stainless steel as a host matrix and a periodic array of water-filled circular scatterers. The sensing mechanism is based on the resonance frequencies confined around the NaI waveguide embedded in the middle of the sensor structure. Numerical simulations are carried out based on the finite element method (FEM). Our results showed that the resonant peak frequency varies significantly with the different NaI–water concentrations in the waveguide. Also, the sensor can differentiate between concentrations from 6%–45% with a 1% step, which is very acceptable for accurate detection and can solve many challenges in medical applications. Further, the sensor provided high performance for all NaI–water concentrations. For example, for a concentration range of 6% − 7%, the sensor has a sensitivity of 1714 Hz, a resolution of 59.5 Hz, a quality factor of 1401, a figure of merit (FOM) of 28, and a signal-to-noise ratio of 2.