title: Ultrasound field measurement using a binary lens.
abstract: Field characterization methods using a scattering target in the absence of a point-like receiver have been well described, in which scattering is recorded by a relatively large receiver located outside the field of measurement. Unfortunately, such methods are prone to artifacts caused by averaging across the receiver surface. To avoid this problem while simultaneously increasing the gain of a received signal, the present study introduces a binary plate lens designed to focus sphericallyspreading waves onto a planar region having a nearly-uniform phase proportional to that of the target location. The lens is similar to a zone plate, but modified to produce a bi-convexlike behavior, such that it focuses both planar and spherically spreading waves. A measurement device suitable for characterizing narrowband ultrasound signals in air is designed around this lens by coupling it to a target and planar receiver. A prototype device is constructed and used to characterize the field of a highly-focused 400-kHz in-air transducer along 2 radial lines. Comparison of the measurements with numeric predictions formed from nonlinear acoustic simulation showed good relative pressure correlation, with mean differences of 10% and 12% over the center 3-dB full-width at half-maximum drop and 12% and 17% over the 6-dB drop.
authors: Gregory
authors: G
authors: Clement
authors: Hideyuki
authors: H
authors: Nomura
authors: Tomoo
authors: T
authors: Kamakura
mesh_terms: D003198:Computer Simulation; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation*; D014463:Ultrasonography / Q000295:instrumentation* / Q000379:methods*
references: IEEE Trans Ultrason Ferroelectr Freq Control. 2010 Oct;57(10):2343-55
references: 20889422
references: Phys Med Biol. 1989 Nov;34(11):1593-607
references: 2685834
references: J Acoust Soc Am. 2000 Jun;107(6):3035-46
references: 10875349
references: J Acoust Soc Am. 2011 Nov;130(5):2789-96
references: 22087907
references: J Ultrasound Med. 1995 May;14(5):367-73
references: 7609015
references: Phys Med Biol. 1999 Jul;44(7):1803-13
references: 10442714
references: Phys Med Biol. 2013 Sep 21;58(18):6263-78
references: 23965825
references: Ultrasonics. 2000 Jan;37(8):565-75
references: 11243460
references: Ultrasonics. 2006 Dec 22;44 Suppl 1:e1567-70
references: 16806363
references: IEEE Trans Ultrason Ferroelectr Freq Control. 2005 Sep;52(9):1608-12
references: 16285460
references: Ultrasonics. 2000 Mar;38(1-8):787-93
references: 10829772
references: J Acoust Soc Am. 2011 Sep;130(3):1115-24
references: 21895054
references: J Acoust Soc Am. 2000 Jul;108(1):441-6
references: 10923906
references: J Acoust Soc Am. 2008 Oct;124(4):2406-20
references: 19062878
references: Ultrasonics. 2002 Aug;39(9):641-8
references: 12206631
references: J Acoust Soc Am. 2011 Jan;129(1):32-46
references: 21302985
references: IEEE Trans Ultrason Ferroelectr Freq Control. 2011 May;58(5):1097-101
references: 21622065
references: IEEE Trans Ultrason Ferroelectr Freq Control. 2005 May;52(5):717-36
references: 16048175