Nov_Dec_AMP_Digital

A D V A N C E D M A T E R I A L S & P R O C E S S E S | N O V E M B E R / D E C E M B E R 2 0 2 0 1 8 Figure 7 illustrates snapshots of the diaphragm motions and acous- tic pressure waves forming and prop- agating in water (25°C) at (a) 13.3 ns, (b) 60 ns, and (c) 0.12 µs, driven simultaneously by a 3 Vpp bipolar peak-to- peak voltage and 37.6 MHz single cycle sine wave. In Fig. 7a, all the dia- phragms moved upward together, with each dia- phragm forming a spheri- cal acoustic wave at 13.3 ns. In Fig. 7b, at 60 ns, four plane wave fronts were ob- served. Because the 80 µm water load was approxi- mately two wavelengths in Fig. 4 — Electrical input impedance of the four diaphragms in the PMUT cell. Fig. 5 — Pulse-echo and normalized spectral responses of the quad diaphragmPMUT cell model. Fig. 6 — A 32×32 array model consisting of 256 (16×16) quad diaphragmPMUT cells in (a) angled planar view and (b) cross-section view. (a) (b) (a) (b) (c) Fig. 7 — Diaphragmmotion and acoustic wave propagation of the 32×32 array model at (a) 13.3 ns, (b) 60 ns, and (c) 0.12 µs.