Simulated transmission efficiency spectrum and acoustic fields for a straight bridge containing a cavity with similar dimensions in the x and y directions.
Spectrum of the transmission efficiency η(f) for a straight bridge containing a cavity, characterized by dimensions r = 2, d = 4, and = 1 μm. The condition η = 1 is indicated by the dashed lines. Insets (a–c): acoustic fields for frequencies corresponding to the EAT peaks in η between 0.1 and 1.8 GHz, including line-plot snapshots of the average out-of-plane particle velocity plotted along directions x and y. Inset (d): schematic diagram of the top part of the bridge and cavity. Mode identification (n, m) is also included. Dimensions are in microns. The colour scale of the image plots is the same as in Fig. 3.