A Spurious-Mode-Suppressed and Q-Enhanced Circular-Crested Lamb Wave Resonator

For the first time, this paper reports an all-modes-excitable circular-crested Lamb wave resonator (LWR). Transverse spurious modes are suppressed because radially propagating circular-crested Lamb waves (LWs) are utilized, which do not have transverse direction. Besides, for the first time, we utilize an energy-concentrating piezoelectric disk, which effectively localizes energy in the central region to enhance the quality factor <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$(Q)$</tex> when combined with the radially propagating circular-crested LWs. Moreover, the operation principle of circular-crested LWR are explained for the first time by detailed theoretical and simulation analysis. The utilization of AlScN with in-plane isotropic piezoelectricity enables the excitation of all circular-crested LW modes, such as A0, S0, A1, and S1 modes. Compared with the straight-crested LWR, the all-modes-excitable circular-crested LWR successfully suppresses the transverse spurious mode near the main S0 mode and achieves 40.7% <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$Q$</tex> enhancement without effective electromechanical coupling coefficient <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$(k_{eff}{}^{2})$</tex> degradation.