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This article proposes a high-precision incremental capacitive angle encoder based on microfabrication technology. Compared to traditional printed circuit board technology, the encoder manufactured by microfabrication technology has higher processing accuracy and better temperature characteristics. Further, the microfabrication technology makes the encoder obtain larger sensitive capacitances and achieve more electrical cycle divisions within a smaller volume. To overcome the effect of the parasitic parameters led by microfabrication technology, electric models were established and analyzed, and the solution was proposed. First, to reduce the parasitic capacitance coupling to the ground, the process materials and fabrication steps are improved and optimized. Then, a differential structure on excitation voltage wires is adopted to minimize the nonlinear error on the measurement results. In addition, the collection electrode interconnection model is optimized to reduce parasitic parameters on the collection and enhance the signal to noise ratio. Both analytical calculation and finite-element analysis results verified the feasibility of the improvement and optimization. Finally, the optimized prototype is fabricated and measured, and the result shows that the prototype can achieve 0.0002° measurement resolution and 0.0012° measurement accuracy within a 58 mm diameter. [ABSTRACT FROM AUTHOR]

Learning with streaming data has attracted much attention during the past few years. Though most studies consider data stream with fixed features, in real practice the features may be evolvable. For example, features of data gathered by limited-lifespan sensors will change when these sensors are substituted by new ones. In this article, we propose a novel learning paradigm: Feature Evolvable Streaming Learning where old features would vanish and new features would occur. Rather than relying on only the current features, we attempt to recover the vanished features and exploit it to improve performance. Specifically, we learn a mapping from the overlapping period to recover old features and then we learn two models from the recovered features and the current features, respectively. To benefit from the recovered features, we develop two ensemble methods. In the first method, we combine the predictions from two models and theoretically show that with the assistance of old features, the performance on new features can be improved and we provide a tighter bound when the loss function is exponentially concave. In the second approach, we dynamically select the best single prediction and establish a better performance guarantee when the best model switches. Experiments on both synthetic and real data validate the effectiveness of our proposal. [ABSTRACT FROM AUTHOR]

Low temperature cofired ceramic (LTCC) ridge waveguide filters are attractive candidates in implementing microwave filters in modern communication systems because of their competitive features, such as low loss, low cost, compact size, lightweight, high-power handling capability, wide spurious-free out-of-band response, and easy integration. However, optimization of LTCC ridge waveguide filters suffers from low speed or imperfect accuracy when the traditional full-wave simulation or the mode-matching method is utilized for analysis. This article makes research on an alternative analysis method based on the network theory for LTCC inline ridge waveguide filters. The method has high speed since it evaluates filter properties by simply making the cumulative product of transfer matrices of all constitutive laminated ridge waveguide (LRWG) sections and laminated coupling (LCP) sections according to their arranging sequence, and transfer matrices of all these sections are calculated from their characteristic parameters (transmission line or equivalent circuit parameters for LRWG or LCP sections) analytically. Another key feature of the method is that all characteristic parameters of LRWG and LCP sections are obtained by searching precreated database. In order to guarantee the analysis accuracy, two special strategies have been proposed and utilized. First, accurate extraction methods of characteristic parameters have been introduced and applied to the creation of a database for LRWG and LCP sections. Second, a piecewise interpolation scheme has been designed and adopted in the database searching process for both kinds of sections. The efficiency of the promoted analysis method has been verified by two analysis examples of LTCC LRWG filters. One is a three-order narrow-band filter and the other is a nine-order wide-band filter. The curves of scattering parameters calculated using the promoted method agree well with the simulated curves and the time consumed by the method is negligible when compared with the simulation time. The effectiveness of the proposed analysis method in filter design is also briefly introduced in this article. [ABSTRACT FROM AUTHOR]

This paper proposes a low-cost and full 360° measurement range inclinometer based on fluidic motion. The inclinometer is fabricated using printed circuit board manufacturing techniques. The principle is via measuring two channels of capacitance changes between three plates, which are partially filled with nonconductive liquid to obtain two amplitude modulation quadrature signals as the resolver. In this inclinometer, the electrode subdivision is changed from the traditional radial direction to a circumferential direction by a triple-eccentric-ring sensing element to achieve full-range measurement capability from 0° to 360°. In addition, the application of a differential detection scheme leads to the dc capacitance C0 being eliminated in the measurement, resulting a high voltage-to-capacitance ratio in a low voltage source requirement. Both analytical calculation and finite-element analysis verified the feasibility of the principle. Furthermore, nonlinear error simulation is conducted and the main effected reason is figured out. Finally, a prototype is fabricated and assembled. Experimental results show that sensor can measure the tilt angle in a range of 360°, with an accuracy of 0.1° and a resolution better than 0.01°. [ABSTRACT FROM AUTHOR]

Here, we examine the concept of frequency domain sensing with solution-gated graphene field-effect transistors, where a sine wave of primary frequency (1f) was applied at the gate and modulation of the power spectral density (PSD) of the drain-source current at 1f, 2f, and 3f was examined as the salt in the gate electrolyte was switched from KCl to CaCl2, and their concentrations were varied. The PSD at 1f, 2f, and 3f increased with the concentration of KCl or CaCl2, with the PSD at 1f being the most sensitive. We further correlated these changes to the shift in Dirac point. Switching the graphene substrate from oxide to hexagonal boron nitride, led to an improved device-to-device reproducibility and a significant reduction of noise, which translated to a higher signal-to-noise ratio and resolution in sensing salt concentrations. The signal-to-noise ratio at 1f was found to be a logarithmic function of KCl or CaCl2 concentration in the 0.1 to 1000 mM range. [ABSTRACT FROM AUTHOR]

This brief proposes novel integrated GaN high-electron-mobility transistor (HEMT) with multichannel Schottky barrier diode (SBD) structures to achieve ultrahigh reverse conduction capability and maintain the blocking characteristic at the same time. The simulative results indicate that the reverse voltage drop and reverse ON-state resistance can be reduced by 38.6% and 38% compared with the traditional metal–insulator–semiconductor HEMT, respectively. Meanwhile, the forward conduction capability, the blocking performances, and the capacitance characteristics are little influenced. Moreover, it is proved that the proposed devices also exhibit superior dynamic performances, indicating the application potential of reducing the power loss of power electronic systems. Finally, the key fabrication flows for the novel devices are presented and discussed. [ABSTRACT FROM AUTHOR]

In this paper, we present the fabrication and characterization of highly flexible indium-gallium–zinc-oxide (IGZO)-based thin-film transistors (TFTs) and integrated circuits on a transparent and thin polymer substrate. Mechanical reliability tests are performed under bending conditions down to a bending radius of 2 mm. All the TFT parameters show only a weak dependence on mechanical strain. TFTs can withstand bending strain up to 0.75% without any significant change in the device operation. Mechanical reliability is further demonstrated to a higher TFT integration level by ring oscillators and 8-b transponder chips operating at a bending radius of 2 mm. [ABSTRACT FROM PUBLISHER]