An acoustoelectric-induced tailorable coupled resonator surface acoustic waveguide

International audienceHere, we introduce a Tailorable coupled resonator surface acoustic waveguide (CRSAW), based on a line defect of elliptical cylinders inside a phononic crystal (PnC) of ZnO pillars over a Si substrate. The designed elliptical resonators allow emerging of a lowly dispersive, single mode shear guiding band inside the local resonance bandgap, owing to their partially broken structural symmetry in comparison with their previously reported counterparts such as pillars and hollow cylinders. Moreover, to introduce reconfigurable waveguiding behavior, we benefit from the acoustoelectric-induced elasticity modulation of ZnO, as a semiconducting piezoelectric. Switching the conductivity of ZnO structures between two limiting low and high values (0.01 S/m to 100 S/m), a considerable waveguiding modulation in FWHM (ΔFWHM=-21%) and guiding frequency (Δfd =-2.81%) are achieved for the designed optimized elliptical cylinder CRSAW, while maintaining acceptable loss value. Benefiting from the proposed ZnO-based elliptical CRSAW, we have achieved simultaneous single mode and low bandwidth surface acoustic waveguiding behavior, without involving significant fabrication complications. The designed structures open up new horizons towards realization of promising building blocks for designing reconfigurable, efficient, and miniature SAW RF-filters, demultiplexers, and Mach-Zehnder devices for wireless communication applications