Browsing by Author "Ergun, A. S."

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Portable low cost ultrasound imaging system
(IEEE, 2016) Sobhani, Mohammad Rahim; Ozum, H. E.; Yaralıoğlu, Göksen Göksenin; Ergun, A. S.; Bozkurt, A.; Electrical & Electronics Engineering; YARALIOĞLU, Göksen Göksenin; Sobhani, Mohammad Rahim
The applications of ultrasound in medicine have been increasing in the last decade either in diagnostics or in treatments. Ultrasound is routinely used in clinical examinations, such as pregnancy exams. On the other hand, a typical ultrasound system costs somewhere between 100k$ to 250k$ because of its (1) expensive ultrasound transducers, (2) large driving electronics, (3) processing and visualization units. High cost and large volume of the ultrasound systems prevent even wider usage of these systems. It is possible to extent the use of ultrasound in clinic environment like a stethoscope, if the size and cost had been reduced orders of magnitude. The aim of this work is to develop an ultraportable and very low cost diagnostic ultrasound imaging probe; by combining inertial sensors with the probes. The manual motion of the probe by the operator's hand movement enables scanning. The position of the probe is tracked using inertial sensors. Finally, the acoustic reflections are registered together by the help of position information of the probe to form an image.
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Vertical cavity capacitive transducer
(American Institute of Physics Inc., 2021-04-01) Yaralıoğlu, Göksen Göksenin; Ergun, A. S.; Bozkurt, A.; Electrical & Electronics Engineering; YARALIOĞLU, Göksen Göksenin
The capacitive micromachined ultrasonic transducer (CMUT) has inherent advantages, such as larger bandwidth and monolithic integration capability with electronics, when compared to the piezoelectric transducer. The most significant shortcoming of the device is the trade-off between input and output sensitivities. Adequate receive sensitivity requires an electric field intensity on the order of 105 V/m, which can be achieved by sub-micron gap heights. However, a small gap limits the device stroke and, consequently, the maximum output pressure. This paper addresses this problem by proposing a CMUT with a vertical cavity. The membrane of the device has a piston part that is surrounded by the sidewalls of a vertical cylinder formed in the substrate. The fringing electric field pulls the piston in the vertical direction; hence, the gap height remains fixed, which alleviates the hard limit on device stroke. The performance of the proposed device is compared to that of the conventional CMUT by theoretical and analytical methods, and a micro-fabrication method is devised. Additionally, a millimeter-scale device has been manufactured and tested as a proof of concept.