Simulation Study on Range and Tilt Angle Detection Based on Air-coupled Leaky Lamb Wave

External sensing based on plate-like structures has attracted much attention in many applications as it can obtain important features of nearby objects in some complex and difficult-to-measure scenarios. In this paper, a simulation study proposes a non-contact detection method for the range and tilt angle of the target objects using air-coupled leaky Lamb waves. A pitch-catch configuration is considered common use and comprises the transmitting and receiving transducers, both positioned on the same side of a thin plate, and the detected object located on the opposite side. A Lamb wave was first excited in the plate, and its leakage in the air was used to detect the object. To investigate the wave field affected by the object, a multiphysics model was established. This model facilitated the visualization of the leaky waves reflected by the object and the new excited Lamb wave in the plate. The signals from this Lamb wave were captured by the receiver, and their changes in waveform and time shift due to the different spatial features of the detected objects were also well illustrated. This entirely non-contact approach to range and tilt angle detection of external objects could be applied in many cutting-edge fields, such as industrial multidimensional awareness and human-computer interaction with smart equipment.