Fast and Robust Capacitive Imaging of Cylindrical Non-Metallic Media

In this paper, a unique approach to the imaging of non-metallic media using capacitive sensing is presented. By using customized sensor plates in single-ended and differential configurations, responses to hidden objects can be captured over a cylindrical aperture surrounding the inspected medium. Then, by processing the acquired data using a novel imaging technique based on the convolution theory, Fourier and inverse Fourier transforms, and exact low resolution electromagnetic tomography (eLORETA), images are reconstructed over multiple radial depths using the acquired sensor data. Imaging hidden objects over multiple depths has wide range of applications, from biomedical imaging to nondestructive testing of the materials. Performance of the proposed imaging technique is demonstrated via experimental results.

Design and Characterization of a Passive Wireless DNA Sensor

This paper presents a concept for a passive wireless DNA sensing platform that exploits a multidisciplinary area, synthesizing the conventional DNA capacitive sensing mechanism and the surface-based conformational characterization throughout DNA immobilization and hybridization. The resonant frequency shift, caused by the change of capacitance throughout DNA immobilization and hybridization and occurring on top of an interdigital capacitor, is monitored by means of an impedance analyzer. 32 samples were measured throughout the experiment and the average capacitance measurements represented a variety of surface charges resulting from DNA molecule immobilization and hybridization. The capacitance changed from 11.58 pF to 114.5 pF when specific ssDNA was attached to electrodes and then increased to 218.6 pF once complementary strand DNA was introduced and hybridized with existing DNA chains. In addition, using impedance analyzer measurements, the resonant frequency decreased from 2.01 MHz to 1.97 MHz in the presence of ssDNA and decreased further down to 0.95 MHz after the complementary strand DNA was deposited.

Modeling the Influence of the Edge Electrostatic Effect on the Transformation Function of Thin-Film Quasi-Differential Capacitive Sensitive Elements

Capacitive sensing elements are the main components of capacitive measuring transducers, which determine most of the metrological characteristics and operational parameters of sensors. First of all, capacitive sensing elements ensure the temporal and parametric stability of sensors, which are the main operational characteristics in such areas as rocket and space and aviation technology, the nuclear industry, in which the instability of sensors and measuring systems based on them can lead to high financial and human losses. etc. At the same time, compensation for lateral capacitive couplings and electrostatic leaks are very important issues, since small changes in capacitance when measuring physical quantities can lead to uninformative measurements in the presence of distortion of electrostatic fields in a capacitive sensing element. In this regard, it is necessary to take into account and simulate the stray fields of electrostatic fields and their influence on measurements.

Electrical Capacitance Tomography (ECT) Electrode Size Simulation Study for Cultured Cell

Cell sensing and monitoring using capacitive sensors are widely used in cell monitoring because of the flexible and uncomplicated design and fabrication. Previous work from many different fields of applications has integrated capacitive sensing technique with tomography to produce cross-sectional images of the internal dielectric distribution. This paper carried an investigation on the capabilities of four 16-channel sensor electrodes with different electrode sizes to detect the change in the dielectric distribution of the cultured cells. All three 16-channel sensor electrodes are designed and simulate on COMSOL 6.3a Multiphysics. The pre-processing results obtained from three finite element models (FEM) of ECT sensor configurations in detecting the cell phantom shows that bigger electrodes size are more sensitive to permittivity distribution.