STUDY OF NEAR FIELD ULTRASONIC BEAM PATTERNS FROM A PULSED LINEAR ARRAY.
Two methods of modeling and visualizing the pressure fields of pulsed planar arrays have been developed. One of these methods has been applied to interactive optimization of the zero**t**h order diffraction pattern for efficient cardiac imaging in the near-field of an array. The trends observed as a result of progressive changes in element phasing and weighting are shown to be consistent with the trends that one would expect from optics and classical work on the far-field of continuous-wave arrays. In addition, the effect of pulse length upon field structure is demonstrated. The methods developed here are also potentially useful for studying the effects of variations in elemental spectra, and element spacing. Comparison is also shown between schlieren pulse photographs from an actual array and gray-scale pulse maps obtained using optimized parameters.
