Design and Analysis of Lithium–Niobate-Based Laterally Excited Bulk Acoustic Wave Resonator with Pentagon Spiral Electrodes

In this paper, we present a comprehensive study on the propagation and dispersion characteristics of A(1) mode propagating in Z-cut LiNbO(3) membrane. The A(1) mode resonators with pentagon spiral electrodes utilizing Z-cut lithium niobate (LiNbO(3)) thin film are designed and fabricated. The proposed structure excites the A(1) mode waves in both x- and y-direction by utilizing both the piezoelectric constants e(24) and e(15) due to applying voltage along both the x- and y-direction by arranging pentagon spiral electrode. The fabricated resonator operates at 5.43 GHz with no spurious mode and effective electromechanical coupling coefficient ([Formula: see text]) of 21.3%, when the width of electrode is 1 µm and the pitch is 5 µm. Moreover, we present a comprehensive study of the effect of different structure parameters on resonance frequency and [Formula: see text] of XBAR. The [Formula: see text] keeps a constant with varied thickness of LiNbO(3) thin film and different electrode rotation angles, while it declines with the increase of p from 5 to 20 µm. The proposed XBAR with pentagon spiral electrodes realize high frequency response with no spurious mode and tunable [Formula: see text] , which shows promising prospects to satisfy the needs of various 5 G high-band application.