Excitation and Detection of 8 MHz Acoustic Waves in Air

Abstract

We have developed transducers and electronic systems that e xcite and detect 8 MHz acoustic waves in air. These transducers and systems have been designed for use in robotic position sensing applications, and for noncontacting surface profile measurements. We have achieved a distance measurement resolution of 0.2 pm out of a 0-0.5 inn range. Our transducers have been constructed utilizing a PZT-5H piezoelectric transducer and an angled fused silica buffer w ith an RTV quarter wavelength matching layer. T heoretical and experimental transducer performances are compared, and highfrequency air transducer design considerations a re presented. computer-controlled rangefinder that utilizes the phase measurement of a reflected signal is discussed. The operation and performance of a