Acoustic ring array with constant beamwidth over a very wide frequency range

A simple technique is presented for maintaining the beamwidth of a transducer constant over a very wide frequency range (over N octaves). A acoustical ring array of six sensors is used to produce a radiation pattern at frequency F 1 . A half-scale model is implemented to give the same directivity pattern at frequency 2F 1 . Two compensation filters, whose frequency responses are derived by imposing the constant beamwidth constraints, are used in the respective array outputs, to produce a constant beamwidth over the octave. The design process is repeated N times, to obtain an acoustical array with constant beamwidth over a very wide frequency range (over N octaves)