Lu J Y, Greenleaf J F
Dept. of Physiol. and Biophys., Mayo Clinic, Rochester, MN.
IEEE Trans Ultrason Ferroelectr Freq Control. 1994;41(5):724-39. doi: 10.1109/58.308509.
The newly developed limited diffraction beams such as the Bessel beams and X waves have a large depth of field and approximate depth-independent property. They have possible applications in medical imaging, color Doppler imaging, tissue characterization, and nondestructive evaluation of materials, and in other wave related physical branches such as electromagnetics and optics. However, limited diffraction beams are currently produced with an annular array transducer that has to be steered mechanically. In this paper, we study the feasibility of steering these beams with a two-dimensional array, and show that there will be almost no distortion of beams if the effective aperture reduction of the array is properly compensated so that the beams have a constant transverse profile as they are steered. In addition, methods for reducing the complexity of the electronic multiplexing of the array elements are proposed. We also investigate the influences of the interelement distance and the size of array elements on the sidelobes and grating lobes of limited diffraction beams as the beams are steered. They are similar to those previously reported for conventional beams.
新开发的有限衍射光束，如贝塞尔光束和X波，具有较大的景深和近似与深度无关的特性。它们在医学成像、彩色多普勒成像、组织表征、材料无损评估以及其他与波相关的物理分支（如电磁学和光学）中具有潜在应用。然而，目前有限衍射光束是由必须进行机械扫描的环形阵列换能器产生的。在本文中，我们研究了使用二维阵列扫描这些光束的可行性，并表明如果适当补偿阵列的有效孔径减小，使得光束在扫描时具有恒定的横向轮廓，那么光束几乎不会产生畸变。此外，还提出了降低阵列元件电子复用复杂性的方法。我们还研究了在光束扫描时，元件间距和阵列元件尺寸对有限衍射光束旁瓣和栅瓣的影响。它们与先前报道的传统光束的影响相似。
