Virtual imaging multiple transducer system

Abstract

In general, the invention comprises a device capable of emitting either acoustic or electromagnetic radiant energy. The device has at least two transducing elements for producing this energy, and at least one reflector which reflects the energy emitted from the transducing elements. The shape of the reflector surface is defined by both an ellipse and a parabola that are rotated coincidentally about a common axis of revolution (hereinafter referred to as a 'para-elliptic' reflector surface), formed by coincidentally rotating, for up to one complete revolution, a section of both geometric shapes about an common axis of revolution that lies in the plane of both geometric shapes. The resulting 'para-elliptic' reflector surface will be characterized by two sets of distinct focal points defining two focal curves. Focused energy will be redirected as if emanating from each focal region, causing each focal region to appear as a virtual source of the energy. The radiation pattern, or beamwidth, of this energy will be substantially frequency invariant. However, the beamwidth for either transducer can be adjusted by moving that transducer to another location. In addition, a means is provided for absorbing or attenuating that radiation which is not reflected from the reflector surface, in order to eliminate interference between reflected and non-reflected radiation.