Abstract: A method and system for obtaining ultrasound data with a sparse array of transducer elements is provided. About one wavelength of a highest operating frequency separates the center of each transducer element from any adjacent transducer element. While this spacing may generate grating lobes, the beamformer of the ultrasound system is configured to filter and isolate information at a harmonic of a fundamental transmit frequency. The resultant two-way beam pattern is less effected by the grating lobes. The image generated as a function of the harmonic information has few artifacts created as a function of the sparse spacing of the transducer elements. Given a set number of beamformer transmit channels, the sparse spacing may allow for a larger aperture width with few artifacts as a result of sparse element spacing. The larger aperture width generates a narrower beam in the azimuthal dimension of a one-dimensional transducer. By generating a narrower beam, better azimuthal resolution may be obtained.

Abstract: An ultrasound or electromagnetic imaging system characterized by a two-dimensional phased array of ultrawideband, ultrasparse transducers. Ultrasparse is defined as an average inter-transducer spacing' which is greater than a .lambda./2 Nyquist spacing for the transducers and which is greater than a pulse length cT, where c is the speed of propagation of a pulse from a transducer in the imaging medium and T is a duration of the pulse. An ultrawideband low Q transient pulse is emitted by each of the transducers during a transmit mode, and the resulting ultrasound image signals are received from the transducers during a receive mode, processed, and displayed. Preferably, the transducers are uniformly weighted and excited and periodically spaced by distance and/or angle within the coordinate system of the two-dimensional phased array such that projections of the transducers onto a coordinate axis of the coordinate system minimally overlap.