Acoustic wave confinement in two-dimensional phononic crystal with multiple nested resonators

Abstract

In this research, a novel phononic crystal (PC) is investigated theoretically to enhance acoustic pressure confinement. It consists of multiple nested resonators based on a tapered configuration. Nested phononic crystal resonator (NPCR) can enhance the acoustic pressure amplification at resonant cavity to a great degree better than the traditional one with same dimensions. The resonant frequency of NPCR is mainly located within outermost phononic crystal resonator’s (PCR) band gap. Meanwhile, it does not move significantly to high frequency with the addition of inner tapered resonators. The enhanced acoustic pressure resonant amplification is attributed to the improvement of the confinement mode owing to the nested structure working as a taper. Then effects of geometrical dimensions of inner PCRs on acoustic confinement are studied. It shows that resonant frequency and resonant acoustic pressure can be affected by the geometric parameters. NPCR has stronger acoustic confinement effects, which are conducive to improve acoustic sensing sensitivity, acoustic signal frequency resolution and acoustic energy harvesting efficiency.