Designing of acoustic 4 × 2 priority encoder using fluid-fluid phononic crystal based ring resonator

In this work, a new design for a 4×2 acoustic priority encoder using fluid-fluid two-dimensional phononic crystal (PnC) ring resonators is presented. The priority encoding operation is enabled by the phononic bandgap characteristics of the mercury-water crystal, which suppress unwanted frequency components while allowing strong confinement and coupling of the resonant mode. At the selected operating frequency of 45.1 kHz, located inside the second bandgap, the ring resonators support constructive interference and selective energy circulation, allowing the highest-priority input to dominate the output logic state. The device structure incorporates two PnC ring cavities and engineered waveguide path lengths to control resonance-based logic discrimination. Performance is validated through high extinction and contrast ratio metrics. The proposed structure provides an acoustically driven alternative for integrated phononic logic circuits, offering potential use in underwater and medical signal-processing applications.