Abstract: A semi-wave transducer is provided that comprises a circular or elliptic transduction shell that has sidewalls captured between identical opposing upper and lower circular or elliptic conical segments (platens), each having a surface geometry of a radially symmetric wave shape that includes a center region and a rim wherein the distance between the center region of the upper and lower platens greater than the distance between the rims of the upper and lower platens. In some embodiments, the surface geometry of the platens may be a jinc function or a recurve function.