Designing a Ultrasound Coupler on a Phononic CrystalPlatform

We are reporting the design of a new ultrasound coupler with the operating frequency of~28.69 MHz, by means of coupling a W1 waveguide to a ring resonator based on a 2-D phononiccrystal (PnC) platform. The 2-D PnC is composed of a periodic array of infinitely long cylindricalrods of steel, arranged in a square lattice of constant a0=6 μm, in air background. The radii of thesteel rods are r0=0.42a0=2.52 μm. Mechanical waves propagating through this particular PnC are ofacoustic types, experiencing a 10-MHz wide phononic bandgap within the frequency range of 25MHz≤ f ≤ 35 MHz. The PnC based W1 waveguide that can be made by removing a row of rods ina straight line guides an acoustic mode within the phononic bandgap. The PnC ring resonator that isassumed to be made by removal of the rods from the periphery of a square of side lengths L=3a0=18μm. Simulations are done by employing plane wave expansion (PWE) and finite element (FE) methods.

کلیدواژه ها:

PnC ، Resonator ، Coupler ، Waveguide