| 摘要 |
An ellipticized singlet azimuth versus elevation optimized and aperture extremized nonspherical acoustic lens antenna of very low or even minimal F-number providing balanced astigmatism for wide angle acoustical applications in underwater sound is described. The acoustic lens has an elliptical periphery and surfaces defined by a system of nonlinear partial differential equations, the surfaces acting together to produce two perfect primary off-axis foci F and F' at a finite distance in back of the lens and two perfect conjugate off-axis foci F INFINITY and F' INFINITY in front of the acoustic lens at infinity; i.e., the lens simultaneously focuses energy from the primary foci F and F' into two off-axis parallel ray plane wave sonic beams directed towards infinity at equal but opposite angles with respect to the acoustic lens axis. The acoustic lens may be built of various materials such as Sylgard rubber RTV 3120 or as a liquid filled thin metal walled shell lens using as the liquid filling any suitable organic or inorganic liquid such as carbon tetrachloride, fluorolube or certain liquid metal mixtures.
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