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This paper describes the design and construction of a line transducer that has a conical-shell directivity pattern. The desired beam orientation is obtained through a combination of physical spacing of the elements of the line, connection of elements, and phasing of the driving current. Minor-lobe reduction is achieved through the use of elements cut to size to provide a shaded distribution. Measurements show the minor lobe to be about 20 dB below the main-lobe level. This particular transducer was designed to obtain bottom- and surface-backscattering data at 40 kc/sec for a grazing angle of 30° through all azimuthal angles. [Work was sponsored by U. S. Naval Ordnance Laboratory.]

This paper describes the design and construction of a line transducer with a conical-shell directivity pattern. The desired beam orientation is obtained through a combination of physical spacing of the elements of the line, connection of elements, and phasing of the driving voltage. Minor-lobe reduction is achieved through the use of elements cut to size to provide a shaded distribution. Measurements show the minor lobe to be about 20 dB below the main-lobe level. This particular transducer was designed to obtain bottom and surface backscattering data at 40 kc/sec for a grazing angle of 30° through all azimuthal angles.