David L. Cosnowski
Mardi C. Hastings
Ohio State Univ., Dept. of Mech. Eng., 206 W 18th Ave., Columbus, OH 43210
Continuous-wave ultrasound for imaging and other measurement applications
requires the use of a separate source and receiver transducer. When this system
is used in air or water, the receiver transducer often detects a signal at the
ultrasonic frequency even in the absence of a target. At ultrasonic
frequencies, significant electromagnetic coupling between the transducers can
occur due to their own and extraneous electromagnetic fields. This study
examines the effect of this interference on the 3-dB sample volume defined by
the crossed beams. The sample volume is determined mathematically by modeling
the source and receiver transducers as plane piston radiators [J. Zemanek,