title: An integrated circuit with transmit beamforming flip-chip bonded to a 2-D CMUT array for 3-D ultrasound imaging.
abstract: State-of-the-art 3-D medical ultrasound imaging requires transmitting and receiving ultrasound using a 2-D array of ultrasound transducers with hundreds or thousands of elements. A tight combination of the transducer array with integrated circuitry eliminates bulky cables connecting the elements of the transducer array to a separate system of electronics. Furthermore, preamplifiers located close to the array can lead to improved receive sensitivity. A combined IC and transducer array can lead to a portable, high-performance, and inexpensive 3-D ultrasound imaging system. This paper presents an IC flip-chip bonded to a 16 x 16-element capacitive micromachined ultrasonic transducer (CMUT) array for 3-D ultrasound imaging. The IC includes a transmit beamformer that generates 25-V unipolar pulses with programmable focusing delays to 224 of the 256 transducer elements. One-shot circuits allow adjustment of the pulse widths for different ultrasound transducer center frequencies. For receiving reflected ultrasound signals, the IC uses the 32-elements along the array diagonals. The IC provides each receiving element with a low-noise 25-MHz-bandwidth transimpedance amplifier. Using a field-programmable gate array (FPGA) clocked at 100 MHz to operate the IC, the IC generated properly timed transmit pulses with 5-ns accuracy. With the IC flip-chip bonded to a CMUT array, we show that the IC can produce steered and focused ultrasound beams. We present 2-D and 3-D images of a wire phantom and 2-D orthogonal cross-sectional images (Bscans) of a latex heart phantom.
authors: Edward L. Ginzton Lab., Stanford Univ., Stanford, CA, USA. iwygant@stanford.edu
authors: Ira O
authors: IO
authors: Wygant
authors: Nafis S
authors: NS
authors: Jamal
authors: Hyunjoo J
authors: HJ
authors: Lee
authors: Amin
authors: A
authors: Nikoozadeh
authors: Omer
authors: O
authors: Oralkan
authors: Mustafa
authors: M
authors: Karaman
authors: Butrus T
authors: BT
authors: Khuri-Yakub
mesh_terms: D004452:Echocardiography; D004582:Electronics, Medical / Q000295:instrumentation*; D004867:Equipment Design; D021621:Imaging, Three-Dimensional / Q000295:instrumentation* / Q000379:methods; D019047:Phantoms, Imaging; D014159:Transducers; D014463:Ultrasonography / Q000295:instrumentation* / Q000379:methods