Guest Editorial: Special Section on Air-Coupled Ultrasound

Abstract

Air-coupled Ultrasound is a challenging field dominated by the drastic impedance mismatch between air and all condensed matter, the low ultrasound velocity in the air, and the rapidly increasing attenuation with frequency. These factors severely limit the applicability of air-coupled ultrasound; however, the potential is enormous. Ongoing research in this field continues to advance in the understanding of novel transduction systems and in the optimization of existing ones, by incorporating novel materials and designs. The emergence of improved transduction systems with better sensitivity, lower noise levels, wider bandwidth, higher frequency, lower cost, smaller size, and lower power consumption together with innovative signal processing and analysis methods, enables improvements of existing applications of air-coupled ultrasound in many different fields and, what is more interesting, the proposal of fully innovative use cases.