An omnidirectional ultrasonic probe, having specific application for connection to the distal end of an esophageal catheter, includes a support member upon which are coaxially mounted a transmitter member, a receiver member, and one or more acoustic reflector members. The acoustic reflector member or...http://www.google.de/patents/US4757821?utm_source=gb-gplus-sharePatent US4757821 - Omnidirectional ultrasonic probe
