Generation of sinc wave by a one-dimensional array for applicationsin ultrasonic imaging

摘要

A new solution to the 2-D scalar wave equation is presented whichndescribes an ultrasonic beam maintaining the lateral field responsenexpressed by the sinc function over a finite depth of field. This newnbeam is realizable with a linear array transducer, and less subject tondiffraction spreading than conventional focused beams, physically, it isna superposition of plane waves having the same wavelength, but travelingnat different angles. It is shown by numerical simulation that the beamncan provide more uniform lateral beamwidth and smoother on-axis fieldnmagnitude over a greater depth of field than the rectangular transducersnand Gaussian apodized transmitters which have been used to increase thenlimited depth of field of conventional focused beams. Compared withncurrently developed limited diffraction beams which must be generated byn2-D array transducers, the beam has a wider lateral beamwidth but withnlower sidelobe levels. In ultrasonic medical imaging, the beam enablesnone to obtain a line focus using a 1-D array transducer and to eliminatenthe diffraction correction required in some applications such as tissuencharacterization