Browsing by Subject "Capacitive sensors"

Now showing 1 - 3 of 3

Open Access
Erratum to "Equivalent circuit-based analysis of CMUT cell dynamics in arrays" [May 13 1016-1024]
(IEEE, 2013-06-03) Oguz, H. K.; Atalar, Abdullah; Köymen, Hayrettin
In the original publication of the paper [1], the funding source was inadvertently omitted from the footnote on page 1016. The footnote should have read "Manuscript received November 20, 2012; accepted February 14, 2013. This work was supported by the Scientific and Technological Research Council of Turkey (TUBITAK) under project grant 110E216. A. Atalar acknowledges the support of the Turkish Academy of Sciences (TUBA)." The authors regret this omission.
Open Access
High resolution dielectric characterization of single cells and microparticles using integrated microfluidic microwave sensors
(Institute of Electrical and Electronics Engineers, 2023-03-01) Seçme, Arda; Tefek, Uzay; Sarı, Burak; Pisheh, Hadi Sedaghat; Uslu, H. Dilara; Akbulut, Özge; Küçükoğlu, Berk; Erdoğan, R. Tufan; Alhmoud, Hashim; Şahin, Özgür; Hanay, M. Selim
Microwave sensors can probe intrinsic material properties of analytes in a microfluidic channel at physiologically relevant ion concentrations. While microwave sensors have been used to detect single cells and microparticles in earlier studies, the synergistic use and comparative analysis of microwave sensors with optical microscopy for material classification and size tracking applications have been scarcely investigated so far. Here we combined microwave and optical sensing to differentiate microscale objects based on their dielectric properties. We designed and fabricated two types of planar sensor: a Coplanar Waveguide Resonator (CPW) and a Split-Ring Resonator (SRR). Both sensors possessed sensing electrodes with a narrow gap to detect single cells passing through a microfluidic channel integrated on the same chip. We also show that standalone microwave sensors can track the relative changes in cellular size in real-time. In sensing single 20-micron diameter polystyrene particles, Signal-to-Noise ratio values of approximately 100 for CPW and 70 for SRR sensors were obtained. These findings demonstrate that microwave sensing technology can serve as a complementary technique for single-cell biophysical experiments and microscale pollutant screening.
Open Access
Three-dimensional electrode integration with microwave sensors for precise microparticle detection in microfluidics
(IEEE, 2024-05-15) Alataş, Yağmur Ceren; Tefek, Uzay; Küçükoğlu, Berk; Bardakçı, Naz; Salehin, Sayedus; Hanay, M. Selim
Microwave sensors integrated with microfluidic platforms can provide the size and permittivity of single cells and microparticles. Among the microwave sensor topologies, the planar arrangement of electrodes is a popular choice owing to the ease of fabrication. Unfortunately, planar electrodes generate a nonuniform electric field, which causes the responsivity of the sensor to depend on the vertical position of a microparticle in the microfluidic channel. To overcome this problem, we fabricated 3-D electrodes at the coplanar sensing region of an underlying microwave resonator. The 3-D electrodes are based on SU8 polymer, which is then metallized by sputter coating. With this system, we readily characterized a mixture composed of 12- and 20 $\mu \text{m}$ polystyrene particles and demonstrated separation without any position-related calibration. The ratio of the electronic response of the two particle types is approximately equal to the ratio of the particle volumes, which indicates the generation of a uniform electric field at the sensing region. This work obviates the need for using multiple coplanar electrodes and extensive processing of the data for the calibration of particle height in a microfluidic channel: as such, it enables the fabrication of more sophisticated microwave resonators for environmental and biological applications.