Acoustic metasurface constructed by periodic parallel Helmholtz resonators for gas sensing applications

Abstract

This study investigates a compact acoustic metasurface of periodic parallel Helmholtz resonators with a resonator defect located in the middle of the structure for gas-sensing applications. Introducing defects into the common resonators' array creates localized resonant modes that affect the gas properties, improving sensitivity. The resonance frequency shift occurs due to the filling gas samples inside the defective structure. Using the finite element method, numerical simulations show that the defective Helmholtz resonator modifies the pressure distribution and reduces the band gap. The study shows that high sensitivity can be achieved by optimizing the number of periodic cells associated with defect modes. Hence, Helmholtz resonator arrays are good candidates for hazardous gas detection. The structure is analysed considering different parameters. The results indicate improved sensitivity with an increasing number of Helmholtz resonators, highlighting the potential use of these systems in environmental monitoring and safety.

Keywords: Defective resonator; Environmental monitoring; Gas sensing; Helmholtz resonators; Periodic structures; Sensitivity.

Fig. 1

Schematic illustrations of (a) the unit cell composed of parallel HR, (b) the defective cell is composed of simple HR, (c) the periodic structure is composed of parallel HRs containing a defective HR in the middle of the structure.

Fig. 2

Mesh illustrations of the periodic structure are composed of parallel HRs containing a defective HR in the middle of the structure.

Fig. 3

Distribution of SPL of seven identical parallel HRs in a periodic arrangement for several specified frequencies at (a) 300 Hz, (b) 316.5 Hz, (c) 360.01 Hz, (e) 400.01 Hz, (f) 460 Hz, and (j) 500 Hz. All structure is filled with air for , , , m, , , , andm.

Fig. 4

Transmittance (using FEM and TMM) and band structure of seven (N = 7) periodic cells of parallel HRs for , , , andm.

Fig. 5

Distribution of SPL in the defective structure at (a) 380.01 Hz, (b) 385.41 Hz, and (c) 390.01 Hz. The defective cell of HR is located between seven identical parallel HRs (N = 7) with different geometry parameters. All structure filled with air for , , , m, , , , m.

Fig. 6

Transmission spectra of the defective structure filled with different gas samples (a) air, (b) , (c) Ar, (d) , and (e) , at , , , m, , , , m. The defective HR is between 7 identical parallel HRs ().

Fig. 7

Transmission spectra of the defective structure filled with different gas samples (a) air, (b) , (c) Ar, (d) , and (e) , at , , , m, , , , m. The defective HR is between 5 identical parallel HRs ().

Fig. 8

Transmission spectra of the defective structure filled with different gas samples (a) air, (b) , (c) Ar, (d) , and (e) , at , , , m, , , , m. The defective HR is between 6 identical parallel HRs ().

Fig. 9

Transmission spectra of the defective structure filled with different gas samples (a) air, (b) , (c) Ar, (d) , and (e) , at , , , m, , , , m. The defective HR is between 8 identical parallel HRs ().

Fig. 10

Transmission spectra of the defective structure filled with different gas samples (a) air, (b) , (c) Ar, (d) , and (e) , at , , , m, , , , m. The defective HR is between 9 identical parallel HRs ().

Fig. 11

Transmission spectra of the defective structure filled with DEB at different concentrations of higher than the normal ratio.