Demonstration of Single Channel Beamforming with Frequency Steerable Acoustic Transducers Using Low-Cost Hardware

Frequency Steerable Acoustic Transducers (FSATs) enable beam steering through frequency-dependent phase relationships, offering a compact and low-cost alternative to conventional phased arrays in ultrasonic inspection. This work presents an hardware-efficient single-channel beamforming approach to perform bidimensional defect imaging by leveraging a novel transducer and its intrinsic quadrature relation among channels. A wideband 90° phase-shifting network was designed and simulated, demonstrating the feasibility of achieving coherent recombination of the received signals through dedicated electronics. The system was validated using an FSAT bonded to a 1 m × 1 m, 1 mm-thick aluminium plate, where two artificial defects were introduced: a metallic cylinder coupled to the surface on the south side at 18 cm and a pair of magnets on the north side at 38 cm. The damages were successfully detected and localized with an accuracy comparable to the object diameter. The proposed architecture reduces the number of acquired channels while maintaining spatial selectivity, demonstrating the potential of FSATs for low-cost non-destructive testing applications.