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[IEEE 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Paris, France (2018.7.8-2018.7.13)] 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Purpose-Built Air Bath for use with NMIA Calculable Cross-Capacitor Measurement Chain
摘要： This paper describes the design of an air bath for maintaining the reference capacitors associated with the new NMIA calculable cross-capacitor measurement system. The air bath is designed to maintain a set temperature in the range 15 °C to 25 °C with a stability of 0.1 mK over the short time periods during which the capacitors are measured.
关键词： temperature control,Capacitance measurement,precision measurements,measurement standards
更新于2025-09-10 09:29:36
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[IEEE 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Paris, France (2018.7.8-2018.7.13)] 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - A Sampling Wattmeter with Extended Frequency Range
摘要： This paper describes the implementation of a sampling wattmeter for the measurement of sinusoidal active and reactive power over the 50 Hz to 6 kHz frequency range, 20 V to 600 V voltage range, and 0.05 A to 80 A current range. The wattmeter is capable of measuring sinusoidal and distorted voltage and current signals with up to 100 harmonics of the fundamental frequency component. Details of the system design, measurement techniques, and signi?cant sources of error are presented.
关键词： power measurement,digital-analog conversion,current measurement,signal synthesis,voltage measurement,permuting capacitance,Analog-digital conversion,quantization
更新于2025-09-10 09:29:36
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[IEEE 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Paris, France (2018.7.8-2018.7.13)] 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Progress on PTB's Pulse-Driven Josephson Impedance Bridge Combined with an AC Quantum Hall Resistance
摘要： Pulse-driven Josephson arrays successfully demonstrated their high potential for impedance metrology in the last years. With their high spectral purity and fundamental accuracy, they are perfectly suited for impedance measurements over the whole complex plane. PTB’s two-terminal impedance bridge is equipped with new electronics to extend the frequency range, to increase the signal amplitude and to simplify the setting of the phase angle. A 1:1 ratio measurement of 10 nF capacitance standards has been carried out between 246 Hz and 40 kHz at a signal amplitude of 75 mV (RMS). The value of a 10 nF capacitance standard is traced back to the ac quantum Hall resistor at PTB using 100 mV (RMS) signal amplitude.
关键词： quantum-Hall Josephson arrays,resistor,AC Josephson voltage standards,pulse-driven impedance measurements,capacitance standard
更新于2025-09-10 09:29:36
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[IEEE 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Paris, France (2018.7.8-2018.7.13)] 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Supplementary Comparison EURAMET.EM-S31
摘要： Within the framework of the Supplementary Comparison EURAMET.EM-S31, the capacitance derived from the quantized Hall resistance at either ac or dc as well as the 10:1 capacitance ratio was intercompared. In addition, the frequency dependence of two traveling ac-dc resistors was intercompared to test the ac-dc resistance standards involved in the particular capacitance realizations. At the end, a good agreement was achieved for all measurands by all participants. By virtue of a link to the NMIA calculable cross-capacitor, a value of the von Klitzing constant in agreement with the 2014 CODATA value was determined.
关键词： von Klitzing constant,quantized Hall resistance,ac-dc resistor,calculable cross-capacitor,Capacitance standard
更新于2025-09-10 09:29:36
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[IEEE 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Paris, France (2018.7.8-2018.7.13)] 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Progress on the New NMIA Calculable Cross-Capacitor
摘要： A new calculable cross-capacitor and associated impedance measurement chain is being built at the National Measurement Institute Australia (NMIA). The new system is intended to reduce the uncertainty of the farad as realised by a calculable capacitor to a few parts in 109, an order of magnitude improvement on existing calculable capacitor systems. We report here on recent progress on the assembly of the calculable capacitor, specifically the measurement of the frequency dependent correction, and the final alignment of the electrodes.
关键词： precision measurements,measurement uncertainty,measurement standards,Capacitance
更新于2025-09-10 09:29:36
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[IEEE 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Paris, France (2018.7.8-2018.7.13)] 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Nonlinearity of the NIST Calculable Capacitor
摘要： We reexamine nonlinearity of the NIST calculable capacitor which is used for realizing the capacitance unit. The “end-effect” is apparent close to the 0.7 pF position. Improved accuracy can be achieved by operating the instrument from 0.2 pF to 0.6 pF.
关键词： nonlinearity,Calculable capacitor,capacitance unit
更新于2025-09-10 09:29:36
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[IEEE 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Paris, France (2018.7.8-2018.7.13)] 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Improved SMD-Based Capacitance Standards
摘要： We have developed improved SMD-based capacitance standards of a nominal value of 10 nF. Other values in a wide range are also possible. The standards feature a small relative deviation from nominal (less than 10×10-6), a low dissipation factor (less than 5×10-6), and a small temperature coefficient (0.5×10-6/K) which strongly reduces the requirements for temperature control. Here, we report on the design and the assembly procedure.
关键词： capacitance standard,SMD capacitor
更新于2025-09-10 09:29:36
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Nano- and submicro-sized three-dimensional shape measuring system using a SAW-based capacitance sensor
摘要： SAW-based capacitance sensors were developed by measuring the changes in the voltage ratio between an output inter-digital transducer (IDT) and an input IDT, induced by the variation in the capacitance between hemi-spherical conductive tips with diameters on the order of micrometers. We derived the transfer and sensitivity functions, which describes the ratio of the variation in the output voltage to the variation in the input voltage with a 2-port network model of a SAW based on Mason’s equivalent electro-acoustic circuit and analytical model for the apex capacitance. We then conducted an experiment to verify and measure the transfer function and the 3-D shape. The system was found to have an average resolution of approximately 10 nanometers. We also used the constructed system to measure nano- and submicro-sized 3-D shapes, and verified that the measurement results were accurate.
关键词： Surface acoustic wave,Capacitance sensor,Transfer function,Sensitivity function,Submicro-sized 3-D shape
更新于2025-09-10 09:29:36
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Simulation Model Development for Packaged Cascode Gallium Nitride Field-Effect Transistors
摘要： This paper presents a simple behavioral model with experimentally extracted parameters for packaged cascode gallium nitride (GaN) field-effect transistors (FETs). This study combined a level-1 metal–oxide–semiconductor field-effect transistor (MOSFET), a junction field-effect transistor (JFET), and a diode model to simulate a cascode GaN FET, in which a JFET was used to simulate a metal-insulator-semiconductor high-electron-mobility transistor (MIS-HEMT). Using the JFET to simulate the MIS-HEMT not only ensures that the curve fits an S-shape transfer characteristic but also enables the pinch-off voltages extracted from the threshold voltage of the MIS-HEMT to be used as a watershed to distinguish where the drop in parasitic capacitance occurs. Parameter extraction was based on static and dynamic characteristics, which involved simulating the behavior of the created GaN FET model and comparing the extracted parameters with experimental measurements to demonstrate the accuracy of the simulation program with an integrated circuit emphasis (SPICE) model. Cascode capacitance was analyzed and verified through experimental measurements and SPICE simulations. The analysis revealed that the capacitance of low-voltage MOSFETs plays a critical role in increasing the overall capacitance of cascode GaN FETs. The turn-off resistance mechanism effectively described the leakage current, and a double-pulse tester was used to evaluate the switching performance of the fabricated cascode GaN FET. LTspice simulation software was adopted to compare the experimental switching results. Overall, the simulation results were strongly in agreement with the experimental results.
关键词： turn-off resistance,GaN FET,MIS-HEMT,SPICE,cascode,behavioral model,parasitic capacitance
更新于2025-09-10 09:29:36
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Boosted electrochemical performance of TiO2 decorated RGO/CNT hybrid nanocomposite by UV irradiation
摘要： Titania decorated RGO/CNT hybrid electrode material was prepared for supercapacitor (SCs) application through facile hydrothermal approach. Combined act of 1D CNTs and 2D RGO assists the uniform in-situ growth of titania towards high surface area mesoporous self-assembled interconnected morphology which is confirmed from FESEM and BET surface area analysis. This interconnected porous network like structure can efficiently allow the better mass transport and decreased contact resistance towards high electrochemical utilization. Electrochemical measurements revealed the superior performance of hybrid nanocomposite comprising of titania/RGO/CNT (TG1C1) which exhibited maximum specific capacitance around 477 F/g at current density 1 A/g. However, this capacitance value was further enhanced up to 537 F/g after 1 hour of UV light irradiation. This enhancement could be ascribed to photo-catalytic effect of TiO2 and corresponding genesis of photo-excited electrons on TiO2 surface which further channelized through interconnected RGO and CNT morphology and hence results in improved specific capacitance. These observations were in good agreement with cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) analysis. The hybrid nanocomposite also showed satisfying energy density and power density. It was also found that prepared hybrid nanocomposites were stable up to 2000 cycles with maximum specific capacitance retention of 92% of initial value.
关键词： Energy storage,RGO-CNT hybrid,Titania,Specific Capacitance
更新于2025-09-10 09:29:36