Z-cut lithium niobate single crystal demonstrates considerable promise for contact-based ultrasonic nondestructive testing and structural health monitoring (SHM) transducers due to its high piezoelectric coefficients, strong electromechanical coupling capability, and environmentally friendly lead-free composition. As a simulation-based theoretical exploration, this study systematically investigates the impact of gap spacing and electrode width in concentric ring configurations on the resonant characteristics and pulse-echo response of ultrasonic transducers by establishing a parametrized finite element model. Numerical simulations reveal that electrode geometry plays a critical role in determining both the effective electromechanical coupling coefficient and echo signal strength. Optimizing the electrode ring width achieved an effective electromechanical coupling coefficient (
Ouyang et al. (Sun,) studied this question.