The ultrasonic radiation mode theory

This paper describes a short history of the radiation mode theory (RMT) in ultrasonics. The RMT originates from electromagnetism where it has proved to be very efficient in the field of wave guides and discontinuities. In ultrasonics the RMT made its entrance only a decade ago and has already proved to be very efficient in describing the interaction of sound with discontinuities such as a step on a plate, a liquid wedge, the extremity of a plate and much more. It is likely that the development of the RMT for 2D isotropic media has come almost to an end. This papers lists some of the results obtained so far. Further extensions to more complicated media re to be expected the coming decade.