Abstract: A capacitive sensor includes a switching capacitor circuit, a comparator, and a charge dissipation circuit. The switching capacitor circuit reciprocally couples a sensing capacitor in series with a modulation capacitor during a first switching phase and discharges the sensing capacitor during a second switching phase. The comparator is coupled to compare a voltage potential on the modulation capacitor to a reference and to generate a modulation signal in response. The charge dissipation circuit is coupled to the modulation capacitor to selectively discharge the modulation capacitor in response to the modulation signal.

Abstract: The determination of electrical parameters (such as instantaneous power, transferred charge, and gas gap voltage) in dielectric barrier discharge (DBD) reactors relies on estimates of key capacitance values. In the classic large-scale sinusoidal-voltage driven DBD, also known as silent or ozonizer discharge, capacitance values can be determined from charge-voltage (Q-V) plot, also called Lissajous figure. For miniature laboratory reactors driven by fast pulsed voltage waveforms with sub-microsecond rise time, the capacitance of the dielectric barriers cannot be evaluated from a single Q-V plot because of the limited applicability of the classical theory. Theoretical determination can be problematic due to electrode edge effects, especially in the case of asymmetrical electrodes. The lack of reliable capacitance estimates leads to a "capacitance bottleneck" that obstructs the determination of other DBD electrical parameters in fast-pulsed reactors. It is suggested to obtain capacitance of dielectric barriers from a plot of the maximal charge versus maximal voltage amplitude (Q(max) - V(max) plot) in a manner analogous to the classical approach. The method is examined using measurements of current and voltage waveforms of a coaxial DBD reactor in argon at 100 mbar driven by square voltage pulses with a rise time of 20 ns and with different voltage amplitudes up to 10 kV. Additionally, the applicability of the method has been shown for the data reported in literature measured at 1 bar of nitrogen-oxygen gas mixtures and xenon.

Abstract: In the oil industry, it is important to measure gas/oil/water flows produced from oil wells. To determine gas and oil production, it is necessary to measure the water-in-liquid ratio (WLR), liquid fraction and some other flow-rate related parameters. A research team from The University of Manchester and Schlumberger Cambridge Research Ltd have developed a non-radioactive gas/oil/water flow experimental apparatus based on a flow conditioning device, multi-modality electrical capacitance tomography (ECT) and microwave sensors. This paper presents a model-based image reconstruction algorithm for the ECT system, which is used to derive WLR and the thickness of liquid layer of oil-continuous annular flows formed by the flow conditioning device. The experimental results of the ECT sensor tested on TUV-NEL's Multiphase Flow Facility are presented.

Abstract: Capacitance and resistivity sensors can be used to continuously monitor soil volumetric water content (θ) and pore-water electrical conductivity (ECp) with non-destructive methods. However, dielectric readings of capacitance sensors operating at low frequencies are normally biased by high soil electrical conductivity. A procedure to calibrate capacitance-resistance probes in saline conditions was implemented in contrasting soils. A low-cost capacitance-resistance probe (ECH2O-5TE, 70 MHz, Decagon Devices, Pullman, WA, USA) was used in five soils at four water contents (i.e., from dry conditions to saturation) and four salinity levels of the wetting solution (0, 5, 10, and 15 dS·m−1). θ was accurately predicted as a function of the dielectric constant, apparent electrical conductivity (ECa), texture and organic carbon content, even in high salinity conditions. Four models to estimate pore-water electrical conductivity were tested and a set of empirical predicting functions were identified to estimate the model parameters based on easily available soil properties (e.g., texture, soil organic matter). The four models were reformulated to estimate ECp as a function of ECa, dielectric readings, and soil characteristics, improving their performances with respect to the original model formulation. Low-cost capacitance-resistance probes, if properly calibrated, can be effectively used to monitor water and solute dynamics in saline soils.

Abstract: An apparatus for satisfying Specific Absorption Rate (SAR) compliance criteria comprising a processor configured to receive a first capacitance measurement from a first capacitance sensor, receive a second capacitance measurement from a second capacitance sensor, determine a relative proximity of a human body to a wireless device based on the first capacitance measurement and the second capacitance measurement, and adjust a radio frequency (RF) transceiver's output power from a first output power limit to a second output power limit based on the determined relative proximity

Abstract: Several newly developed sensors based on capacitance and frequency techniques have simplified real-time determination of soil water content (θ). The 10HS sensor is one of the most recent developments in capacitance sensors. However, up to now, little is known about the accuracy of this sensor, and the dependency of its measurements on soil type and environmental factors. In this study, the performance of the 10HS sensor was investigated through experiments using liquids with known dielectric properties and experiments in a set of porous media exhibiting a wide range of properties. The response of the 10HS sensor in bilayered systems was also investigated. The experimental results suggested that there is a distinct instrument sensitivity to soil type, indicating the need for individual soil calibration. A set of specific calibration equations for the various porous materials studied were proposed. It was shown that the 10HS sensor is able to provide reasonably accurate relative permittivity (er) me...

Abstract: This paper presents simulations of an air plasma discharge at atmospheric pressure in a point-to-plane configuration with a dielectric layer in the path of the discharge. First, the dielectric layer is placed on the cathode plane and we study the influence of the permittivity and thickness of the dielectric on the positive streamer discharge dynamics and the dielectric surface charging. We show that the velocity of the surface discharge on the dielectric surface depends on the capacitance of the dielectric layer and decreases as this capacitance increases. Conversely, the amount of positive surface charge deposited by the positive surface discharge on the dielectric surface is not directly related to the value of the capacitance of the dielectric layer. However, the amount of surface charge deposited increases as the capacitance of the dielectric layer increases. Second, the dielectric layer is placed in the air gap as an obstacle for the propagation of the first streamer discharge ignited at the point electrode. In this case, after the impact on the dielectric, the first discharge spreads along the upper dielectric surface and we show that, depending on the location of the dielectric layer, its permittivity, its thickness and its opacity to radiation, a second discharge may reignite or not below the dielectric layer. During the discharge dynamics, positive charges are deposited on the upper surface of the dielectric and negative charges are deposited on its bottom surface. For all conditions studied in this work, we show that surface charge deposition on both faces of the dielectric layer has a small influence on the discharge reignition below the dielectric layer. Finally, with two closely spaced dielectric layers in the path of the discharge, a series of spreading/reignition for each dielectric layer is observed.

Abstract: Capacitance sensing circuits and methods are provided. A dual mode capacitance sensing circuit includes a capacitance-to-voltage converter having an amplifier and an integration capacitance coupled between an output and an inverting input of the amplifier, and a dual mode switching circuit responsive to mutual mode control signals for a controlling signal supplied from a capacitive touch matrix to the capacitance-to-voltage converter in a mutual capacitance sensing mode and responsive to self mode control signals for controlling signals supplied from the capacitive touch matrix to the capacitance-to-voltage converter in a self capacitance sensing mode, wherein the capacitance sensing circuit is configurable for operation in the mutual capacitance sensing mode or the self capacitance sensing mode.

Abstract: The unique electronic properties of graphene are exploited for field-effect sensing in both capacitor and transistor modes when operating the sensor device in electrolyte. The device is fabricated using large-area graphene thin films prepared by means of layer-by-layer stacking. Although essentially the same device, its operation in the capacitor mode is found to yield more information than in the transistor mode. The capacitor sensor can simultaneously detect the variations of surface potential and electrical-double-layer capacitance at the graphene/electrolyte interface when altering the ion concentration. The capacitor-mode operation further facilitates studies of the molecular binding-adsorption kinetics by monitoring the capacitance transient.

Abstract: We report on the fabrication of an all-inkjet printed capacitor on a flexible substrate for future use in wearable electronics. Each layer of the capacitor was deposited exclusively using inkjet printing. The capacitor is constructed using the parallel plate structure. A silver nanoparticle dispersion was chosen for the conductive inkjet ink with a curing process of 150 °C for 10 minutes. An inkjet printable photoresist (SU-8) is chosen for the dielectric layer which requires room temperature UV curing for 10 seconds. The theoretical capacitance is calculated to be 48.59 pF using a relative permittivity of 4.2 for SU-8. The discrepancy is around 0.2% to actual capacitance measured at 100 Hz.

Abstract: An arc-electrode capacitive sensor has been developed for quantitative characterization of permittivity of cylindrical dielectric rods. The material property of the cylindrical test piece can be inversely determined from the sensor output capacitance based on a theoretical model. For the modeling process, the electrostatic Green's function due to a point source exterior to a dielectric rod is derived. The sensor output capacitance is numerically calculated using the method of moments (MoM), in which the integral equation is set up based on the electrostatic Green's function. Numerical calculations on sensor configuration optimization are performed. Calculations also demonstrate the quantitative relationship between the sensor output capacitance and the test-piece dielectric and structural properties. Capacitance measurements on different dielectric rods with different sensor configurations have been performed to verify the validity of the numerical model. Very good agreement (to within 3%) between theoretical calculations and measurement results is observed.

Abstract: In this paper, we report a novel method of droplet sensing in a two-plate digital microfluidic system (DMS) based on coplanar capacitance measurement. The total capacitance between the two adjacent electrodes on the lower plate depends on the position of the droplet. Both numerical and experimental results show that the capacitance is maximal at the midpoint between two electrodes. The value of maximum capacitance increases with the volume of the droplet. Further, the measured capacitance is a function of the gaps between the electrodes as well as the plates. This new method of droplet sensing adds to the functionality of DMSs by allowing single plate measurement.

Abstract: A capacitive sensor has been developed for the purpose of measuring the permittivity of a cylindrical dielectric that coats a conductive core cylinder. The capacitive sensor consists of two identical curved patch electrodes that are exterior to and coaxial with the cylindrical test piece. The permittivity of the cylinder is determined from measurements of capacitance by means of a physics-based model. In the model, an electroquasistatic Green function due to a point source exterior to a dielectric-coated conductor is derived, in which the permittivity of the dielectric material may take complex values. The Green function is then used to set up integral equations that relate the unknown sensor surface charge density to the imposed potentials on the electrode surfaces. The method of moments is utilized to discretize the integral equation into a matrix equation that is solved for the sensor surface charge density and eventually the sensor output capacitance. This model enables the complex permittivity of the dielectric coating material, or the geometry of the cylindrical test-piece, to be inferred from the measured sensor capacitance and dissipation factor. Experimental validation of the numerical model has been performed on three different cylindrical test-pieces for two different electrode configurations. Each of the test-pieces has the structure of a dielectric coated brass rod. A good agreement between measured and calculated sensor capacitance (to an average of 7.4%) and dissipation factor (to within 0.002) was observed. Main sources of uncertainty in the measurement include variations in the test-piece geometry, misalignment of sensor electrodes, strain-induced variation in the test-piece permittivity and the existence of unintended air gaps between electrodes and the test-piece. To demonstrate the effectiveness of the sensor, measurements of capacitance have been made on aircraft wires and the permittivity of the insulation inferred. A significant change in permittivity was observed for thermally degraded wires.

Abstract: A method calculates a correction factor for one or more of capacitance sensors and generates a current from a mutual capacitance of one of the capacitance sensors. The method applies the correction factor to the generated current to generate a corrected current and converts the corrected current to a digital value. The method determines a position of one or more conductive objects in proximity to the one or more capacitance sensors based on the digital value.

Abstract: Apparatuses and methods of an integrated capacitance model circuit are described. A capacitance model circuit is disposed on a common carrier substrate of an integrated circuit (IC) having a capacitance-sensing device. The capacitance model circuit is configured to model a capacitance of an external sense array. The capacitance model circuit is programmable.

Abstract: A novel semiconductor variable capacitor is presented. The semiconductor structure is simple and is based on a semiconductor variable MOS capacitor structure suitable for integrated circuits, which has at least three terminals, one of which is used to modulate the equivalent capacitor area of the MOS structure by increasing or decreasing its DC voltage with respect to another terminal of the device, in order to change the capacitance over a wide ranges of values. Furthermore, the present invention decouples the AC signal and the DC control voltage avoiding distortion and increasing the performance of the device, such as its control characteristic. The present invention is simple and only slightly dependent on the variations due to the fabrication process. It exhibits a high value of capacitance density and, if opportunely implemented, shows a linear dependence of the capacitance value with respect to the voltage of its control terminal.

Abstract: There are provided an apparatus for sensing capacitance, a method for sensing capacitance, and a touch screen apparatus. The apparatus for sensing capacitance includes; a first integration circuit unit including a first capacitor charged by a change in capacitance occurring in a sensing electrode; a comparison circuit unit comparing a level of an output signal of the first integration circuit unit with a predetermined reference level; and a noise removal unit including a plurality of switches operating according to an output of the comparison circuit unit, wherein the comparison circuit unit controls an operation of each of the plurality of switches to discharge charges charged in the first capacitor when the level of the output signal of the first integration circuit unit is higher than the reference level.

Abstract: A variable capacitance element includes a piezoelectric substrate, a buffer layer located on the piezoelectric substrate with an orientation, a dielectric layer located on the buffer layer and having a relative dielectric constant that varies in accordance with an applied voltage, and a first electrode and a second electrode arranged to apply an electric field to the dielectric layer.

Abstract: There is provided a capacitance sensing apparatus including: a driving circuit unit applying a driving signal to a first capacitor; a first integrating circuit unit including a second capacitor charged by a change in capacitance generated in the first capacitor based on the driving signal to generate a first output voltage; and a second integrating circuit unit including a third capacitor charged by a change in capacitance generated in the second capacitor to generate a second output voltage, wherein a level of the second output voltage is changed at least twice during a single period of the driving signal applied to the first capacitor.

Abstract: According to one aspect, embodiments described herein provide a sensor comprising a housing configured to be coupled around a portion of the transmission line, at least one probe capacitor configured to encircle the portion of the transmission line with the housing coupled around the portion of the transmission line, a measurement capacitor configured to encircle the portion of the transmission line with the housing coupled around the portion of the transmission line, a capacitance acquisition system, and a voltage measurement system, wherein the capacitance acquisition system is configured to determine a first value related to capacitance of the at least one probe capacitor, and based on the first value, determine a second value related to capacitance of the measurement capacitor, and wherein the voltage measurement system is configured to receive a signal providing the second value and calculate a third value related to a voltage level of the transmission line.

Abstract: We report on a variable capacitor that is formed between Schottky contacts and the two dimensional electron gas (2DEG) in a planar metal-semiconductor-metal structure. Device capacitance at low bias is twice the series capacitance of anode and cathode, enhancing to a maximum value, Cmax, at a threshold voltage, before reaching a minimum, Cmin, lower than the geometric capacitance of the coplanar contacts, thus resulting in ultra high Cmax/Cmin tuning ratio. Sensitivity, the normalized change of capacitance with voltage, is also very large. The dense reservoir of the 2DEG charge maintained between contacts is shown to be responsible for this remarkable performance.

Abstract: A multiphase DC-to-DC converter is disclosed herein, which includes at least one DC-to-DC converting module. Each DC-to-DC converting module at least includes a first output inductor, a second output inductor and a current detector. The current detector is configured for detecting currents pass through the first output inductor and second output inductor. The current detector includes a first resistance, a second resistance, a first capacitor, a second capacitor, and a third resistance. The third resistance is directly or indirectly coupled between the first capacitor and a load circuit, and directly or indirectly coupled between the second capacitor and the load circuit, such that when the first capacitor is charged, a portion of the current charging the first capacitor passes through the second capacitor.

Abstract: This work develops simple capacitance sensors which can measure the void fraction in the annular flow of a vertical pipe. In this work plate- and ring-type sensors are considered. For the determination of the optimal gap size for each sensor type, several numerical tests are performed and numerical results show that the angle of the gap between 1 and 1.5 rad gives more outstanding performance than others for the plate-type sensor, and in the case of the ring-type sensor the larger gap distance to radius ratio gives better result. Additionally, these numerical trends are successfully compared with static phantom experiments.

Abstract: In a capacitor body of a multilayer capacitor, one second capacitor portion is sandwiched between two first capacitor portions. An ESR is controlled by setting a width of lead portions of third and fourth internal electrodes disposed in the second capacitor portion to be less than that of lead portions of first and second internal electrodes disposed in the first capacitor portions and by changing ratios between the first and second capacitor portions in the width of the lead portions and in the number of stacked internal electrodes. In the first capacitor portions, current paths from the internal electrodes to an external terminal electrode are widely distributed so that the first capacitor portions have a relatively low ESL, and accordingly, the ESL of the entire multilayer capacitor is reduced.

Abstract: Electrical Capacitance Tomography (ECT) is a method for the determination of the dielectric permittivity in the interior of the object based on exterior capacitance measurements. The principle is based on inter-electrode capacitance measurements which are done by placing electrodes around the dielectric medium which is generally made of PVC and the medium that is to be imaged is placed inside this PVC cylinder. As we know capacitance varies with respect to dielectric permittivity, area of the plates and distance between the plates. In this technique area and distance between the electrodes are kept constant, so the only parameter that influences the capacitance detected is the dielectric permittivity of the medium inside there by making this technique a suitable method for distinguishing substances of differing dielectric properties. . This technique has got several advantages such as low cost, rapid response, high robustness and no radiation hazard. Till now it is used in Oil Industries for detecting bubbles in the oil flow based on the difference in their dielectric permittivity. The aim of this paper is to apply this technique in medical application by modeling an ECT system that can be used for imaging of the bone, as human tissues shows a change in the dielectric properties, which will thereby open a new path in the field of medical imaging. The entire technique is implemented with the help of LabVIEW. Results obtained shows that this technique can be used for the imaging of bone.

Abstract: This paper presents a programmable capacitive sensing circuit for multi-touch applications, especially enabling mutual capacitance sensing in a large-sized touch panel (over 10-inches). To control the offset of the capacitive sensor, the circuit, based on a switched-capacitor integrator, internally includes a cancelling capacitor array to discharge a feedback capacitor and prevent excessive accumulation. Also, the feedback capacitor array can make the sensitivity of the sensor programmable. With programmable capacitors, this design can make the sensor more compatible with various panels and use a lower feedback capacitor than that of a conventional switched-capacitor. The capacitive interface circuit for a large-sized touch panel has 1728 channels (54×32), which simultaneously sense the capacitance variation during each line driving for mutual capacitance sensing. In addition, charge integration is repeated to increase the signal-to-noise ratio (SNR). The performance of the proposed topology is evaluated mainly with a 10.1-inch LCD touch panel. The measured SNR of the sensor is 23dB at a 60Hz frame rate with twenty repetitions of charge integration. The prototype IC is implemented in a 0.35-um CMOS technology.

Abstract: [Theme] To provide a chip capacitor capable of easily and rapidly accommodating a plurality of types of capacitance values using a common design and a method for manufacturing the chip capacitor. [Solution] A chip capacitor 1 includes a substrate 2 , a first external electrode 3 , a second external electrode 4 , capacitor elements C 1 to C 19 , and fuses F 1 to F 9 disposed on the substrate 2 . The capacitor elements C 1 to C 19 respectively include a first electrode film 11 , a first capacitance film 12 on the first electrode film 11 , a second electrode film 13 disposed on the first capacitance film 12 and facing the first electrode film 11 , a second capacitance film 17 on the second electrode film 13 , and a third electrode film 16 disposed on the second capacitance film 17 and facing the second electrode film 13 and are connected between the first external electrode 3 and the second external electrode 4 . The fuses F 1 to F 9 are each interposed between the capacitor elements C 1 to C 19 and the first external electrode 3 or the second external electrode 4 and are capable of disconnecting each of the capacitor elements C 1 to C 19.

Abstract: A capacitance element body 2 is configured by two or more capacitors, the capacitors being formed of a dielectric layer 3 and at least three internal electrodes, the internal electrodes each being laminated via the dielectric layer 3 and arranged to allow a center of gravity of an electrode body forming electrostatic capacitance to be arranged on a straight line in a lamination direction. In the capacitance element body 2 , said two or more capacitors are serially connected in a lamination direction of the internal electrodes. Furthermore, external terminals 20 to 23 , each being electrically connected to an electrode body forming electrostatic capacitance, are formed in side surfaces of the capacitance element body 2.

Abstract: In one embodiment, a method includes dividing a first amount of charge between a capacitance of a touch sensor and a compensation capacitor. The division of the first amount of charge results in a first voltage at an input node. The method also includes isolating the capacitance of the touch sensor from the compensation capacitor; and applying a reference voltage at the input node and a supply voltage at the compensation capacitor. The application of the reference voltage at the input node induces a second amount of charge proportional to a difference between the first voltage and the reference voltage on an integration capacitor. The method also includes determining a first difference between the first voltage and the reference voltage based on a second amount of charge on the integration capacitor; and determining whether a touch input to the touch sensor has occurred based on the first difference.