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1. (WO2017041166) SYSTEMS AND METHODS OF COMBINED PHASED-ARRAY AND FRESNEL ZONE PLATE BEAMFORMING EMPLOYING DELAY-CORRECTED FRESNEL SUB-APERTURES

Pub. No.:    WO/2017/041166    International Application No.:    PCT/CA2016/050193
Publication Date: Fri Mar 17 00:59:59 CET 2017 International Filing Date: Fri Feb 26 00:59:59 CET 2016
IPC: G01S 15/89
A61B 8/00
G01S 7/523
Applicants: DALHOUSIE UNIVERSITY
Inventors: BROWN, Jeremy
LATHAM, Katherine
Title: SYSTEMS AND METHODS OF COMBINED PHASED-ARRAY AND FRESNEL ZONE PLATE BEAMFORMING EMPLOYING DELAY-CORRECTED FRESNEL SUB-APERTURES
Abstract:
Systems and methods are disclosed for performing imaging with a crossed- electrode ultrasound transducer array, where ultrasound transducer array is configured for focusing in one direction via conventional time-delay phased array beamforming, and for focusing in a second direction via a Fresnel aperture formed via the application of bias voltages. The ultrasound transducer array connections are switched between transmit and receive operations, such that the Fresnel aperture is generated in the first direction upon transmit, and in the second direction upon receive. One or both of the transmit Fresnel aperture and the receive Fresnel aperture are configured as a set of delay-corrected Fresnel sub-apertures, where the delay associated with each Fresnel sub-aperture is selected to compensate for variations in path lengths between the Fresnel sub-apertures and the focal point. The use of multiple Fresnel sub-apertures and time delay corrections overcomes problems associated with steering-induced bandwidth degradation.