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We have developed and here propose a novel capacitive micromachined ultrasound transducer (CMUT) cell structure that has a long breakdown lifetime against high DC bias voltage. The structure extends the distance between the top and bottom electrodes by means of an additional insulating layer inserted at the cavity edge. The structure's electric breakdown voltage was increased by 1.2 times so that...
Capacitive micromachined ultrasound transducers (CMUTs) have emerged as a candidate for ultrasound transducers to achieve high resolution imaging. To achieve high quality tissue harmonic imaging (THI) with a sufficient signal-to-noise ratio (SNR), we propose a novel harmonic signal extraction technique named amplitude modulated pulse inversion (AMPI) with low frequency (LF) component. The AMPI+LF...
Tissue harmonic imaging (THI) based on amplitude modulation by controlling the number of driving elements (AM-CNDE) with a prototype CMUT probe is demonstrated. AM-CNDE requires multiple transmission pulses and the amplitude of each pulse is controlled by changing the number of driving channels in a probe. The harmonic signals are extracted clearly even if the CMUTs have large nonlinearity. The beam...
A capacitive micromachined ultrasonic transducer (CMUT) was fabricated using a standard 0.25-mum CMOS backend-of-line process. By adopting the planarization of dielectric material between the upper and lower electrodes by chemical mechanical polishing (CMP), we achieved a time-dependent dielectric breakdown (TDDB) lifetime exceeding 10 years at a DC stress voltage of 192 V. In the case of DC and AC...
The purpose of this study is to realize the mechanically-controllable needle-insertion system using the CMTD (curved multi-tube device) which was developed by authors. A CMTD, which consists of a straight outer needle and a curved inner needle, was developed for minimally-invasive surgery and needle insertion. And we use ultrasound as a sensing device to detect the position of tumor and the orientation...
The purpose of this study is to realize the mechanically-controllable needle-insertion system using the CMTD (Curved Multi-Tube Device) which was developed by authors. A CMTD, which consists of a straight outer needle and a curved inner needle, was developed for minimally-invasive surgery and needle insertion. And we use ultrasound as a sensing device to detect the position of tumor and the orientation...
Measurement of blood flow velocity using Doppler ultrasound has become an important noninvasive tool not only in the diagnosis of cardiovascular disease but also in physiological measurement. Physiological blood flow velocities in common carotid artery (CCA) is altered markedly with advancing age. It is unknown that regular aerobic exercise training can alter and improve blood flow velocity waveforms...
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