EMISSION OR RECEPTION OF ACOUSTIC RADIATION WITH A SONAR ANTENNA

摘要

1530035 Subaqueous transducers; acoustic lenses ETAT FRANCAIS MINISTER FOR NATIONAL DEFENCE 6 May 1976 [27 June 1975] 18689/76 Headings H4J and H4X [Also in Division G1] A sonar antenna 1 comprises an acoustic lens 6 having a focal surface 12 on which is an array of columns 15 of electroacoustic transducers, the array comprising two groups of columns having different resonance frequencies, the columns of the two groups being interspersed. The lens 6 is filled with a mixture of fluorinated and/or chlorinated hydrocarbons and has a 200 degree acoustic window 9 limited by a wall 11 lined with absorbent material 11a. In operation, columns of the two groups alternate and alternate columns of the same group working at the same frequency are operated in antiphase. The columns may be switched in sets for scanning. The antenna gives enhanced resolution and higher contrast images than obtained previously.