Ultrasonic Transmit Beam Steering Using Slitted Transducer Design

Advancements in ultrasonic imaging sensors (UISs), such as improvements in cost-effectiveness, low power consumption, and suitability for challenging environments, have been useful for drone navigation. However, existing microelectromechanical systems (MEMS) transducer arrays suffer from limitations due to the non-uniform stress distribution of the thin-film layers, which changes the resonant frequency of devices. To address this, a novel sector slitted transducer design was proposed, which enhances the acoustic pressure output while maintaining mechanical stability and reduces the sensitivity of the resonant frequency to residual stresses. In this study, finite element analysis was used to model the slitted transducer design, which demonstrated minimal variation in resonant frequencies under different stress conditions. The MEMS transducer array simulations have displayed effective beam-steering capabilities using different phase profiles and validation of performance metrics through the Fresnel and Fraunhofer diffraction propagations. Both the imaging resolution and signal-to-noise ratio (SNR) of the array were evaluated over various distances. The figures-of-merit (FoM) of the sector-slitted design indicate that the transducer array is 1.6 to 30 times smaller than existing designs while being able to generate 26 to 965 times greater acoustic pressure than the other designs reported in the literature. Thus, the array promises enhanced performance in 3D range-finding and imaging applications for drones and mobile devices, offering compactness and efficiency. Future applications could leverage these advancements to improve autonomous navigation and environmental sensing in complex scenarios.