title: Performance and characterization of new micromachined high-frequency linear arrays.
abstract: A new approach for fabricating high frequency (> 20 MHz) linear array transducers, based on laser micromachining, has been developed. A 30 MHz, 64-element, 74-microm pitch, linear array design is presented. The performance of the device is demonstrated by comparing electrical and acoustic measurements with analytical, equivalent circuit, and finite-element analysis (FEA) simulations. All FEA results for array performance have been generated using one global set of material parameters. Each fabricated array has been integrated onto a flex circuit for ease of handling, and the flex has been integrated onto a custom printed circuit board test card for ease of testing. For a fully assembled array, with an acoustic lens, the center frequency was 28.7 MHz with a one-way -3 dB and -6 dB bandwidth of 59% and 83%, respectively, and a -20 dB pulse width of -99 ns. The per-element peak acoustic power, for a +/- 30 V single cycle pulse, measured at the 10 mm focal length of the lens was 590 kPa with a -6 dB directivity span of about 30 degrees. The worst-case total cross talk of the combined array and flex assembly is for nearest neighboring elements and was measured to have an average level -40 dB across the -6 dB bandwidth of the device. Any significant deviation from simulation can be explained through limitations in apparatus calibration and in device packaging.
authors.affiliation: Imaging Research, Sunnybrook and Women's College Health Science Centre, University of Toronto, Toronto, ON M4N 3M5, Canada. lukacs@sten.sunnybrook.utoronto.ca
authors.forename: Marc
authors.initials: M
authors.lastname: Lukacs
authors.forename: Jianhua
authors.initials: J
authors.lastname: Yin
authors.forename: Guofeng
authors.initials: G
authors.lastname: Pang
authors.forename: Richard C
authors.initials: RC
authors.lastname: Garcia
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Cherin
authors.forename: Ross
authors.initials: R
authors.lastname: Williams
authors.forename: Jim
authors.initials: J
authors.lastname: Mehi
authors.forename: F Stuart
authors.initials: FS
authors.lastname: Foster
mesh_terms: D017076:Computer-Aided Design; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007089:Image Enhancement / Q000295:instrumentation*; D007090:Image Interpretation, Computer-Assisted / Q000295:instrumentation*; D016014:Linear Models; D008904:Miniaturization; D011846:Radio Waves; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014159:Transducers; D014463:Ultrasonography / Q000295:instrumentation*