The Diffracted Transient Field of the Rectangular Piston in Loss-Less and Absorbing Media

In this work the analysis of the acoustic field diffracted by a rectangular piston is performed on the basis of the impulse response theory. In the case of rectangular geometries some analytical difficulties arise in applying the classical method proposed by Stepanishen (1971), as pointed out by Lockwood and Willette (1973). Here we propose another approach able to overcome these difficulties. The main characteristic of our approach consists in considering the field at the instant t as a function of the spatial coordinates x,y, while Stepanishen’s basic idea was to consider the field at the point x,y as a function of time t. Further, starting from a modified wave equation, an approximate solution for the impulse response of the rectangular piston will be presented also for the case of lossy media.