New dual-focalization ferroelectret-based array for air-coupled ultrasonic inspection of textiles

This work presents a design methodology for half-curved airborne ultrasonic arrays based in cellular ferroelectret film. The geometry of the array proposed allows us focus naturally in the vertical plane and electronically in the horizontal one, obtaining similar spatial resolution in both directions. Theoretical predictions and simulated results were validated with a developed array prototype designed to operate at frequencies between 50 kHz and 300 kHz. The potential of the device is shown by inspecting different textile samples in transmission mode. This multitransducer design is a low cost alternative to the use of composite 2D arrays in noncontact ultrasonic inspections.