Current Issue : July - September Volume : 2018 Issue Number : 3 Articles : 5 Articles
The Microwave Power Transmission (MPT) is the possibility of feeding a system without contact by using microwave energy.The\nchallenge of such system is to increase the efficiency of transmitted energy from the emitter to the load. This can be achieved by\nrectifying the microwave energy using a rectenna system composed of an antenna of a significant gain associatedwith a rectifier with\na good input impedance matching. In this paper, a newmultiband antenna using the microstrip technology and fractal geometry is\ndeveloped. The fractal antenna is validated into simulation and measurement in the ISM (industrial, scientific, and medical) band\nat 2.45GHz and 5.8GHz and it presents a wide aperture angle with an acceptable gain for both bands. The final antenna is printed\nover an FR4 substrate with a dimension of 60 Ã?â?? 30mm2.These characteristics make the antenna suitable for a multiband rectenna\ncircuit use....
Due to their high power density and appropriateness for small circuits integration,\nswitched-capacitor (SC) converters have gotten more interests. Applying the soft-charging technique\neffectively eliminates the current transient that results in a higher power density and a higher\nfundamental efficiency. Achieving the complete soft-charging operation is impossible by using the\nconventional control diagram for any SC converter topology. In this paper, we proposed a split-phase\ncontrol to achieve the complete soft-charging operation in a power switched-capacitor (PSC) converter.\nThe proposed control diagram was designed for a 1-to-4 PSC converter (two-level of the PSC converter).\nThe implemented split-phase diagram successfully controls eight switches to exhibit eight modes\nof operation. In addition to the current transient elimination, the complete soft-charging allows us\nto reduce capacitor sizes. However, reducing capacitor size negatively increases the output voltage\nripple; hence, an output LC filter is needed. The complete soft-charging achievement accomplishes\na 96% efficiency due to the lower output impedance and the dead time switching. LT-Spice software\nhas been used to verify the proposed control and the results were compared with hard-charging and\nincomplete soft-charging operations....
High step-up nonisolated multicellular dc-dc converter has been newly proposed for PV microconverters. The multicellular\nconverter consists of the nonisolated step-up cell converters using bidirectional semiconductor switches, and these cell converters\nare connected in Input Parallel Output Series (IPOS). The voltage transformation ratio of the step-up converter is ...
Interconnect reliability has been regarded as a discipline that must be seriously\ntaken into account from the early design phase of integrated circuit (IC). In\norder to study the status and trend of the interconnect reliability, a comprehensive\nreview of the published literatures is carried out. This can depict the\nglobal trend of ICs� interconnect reliability and help the new entrants to understand\nthe present situation of this area....
It is becoming more important for electronic devices to operate stably and reproducibly\nunder harsh environments, such as extremely low and/or high temperatures, for robust and practical\napplications. Here, we report on the effects of atomic-layer-deposited (ALD) aluminum oxide\n(Al2O3) passivation on multilayer molybdenum disulfide (MoS2) thin-film transistors (TFTs) and their\ntemperature-dependent electrical properties, especially at a high temperature range from 293 K to\n380 K.With the aid of ultraviolet-ozone treatment, an Al2O3 layer was uniformly applied to cover the\nentire surface of MoS2 TFTs. Our Al2O3-passivated MoS2 TFTs exhibited not only a dramatic reduction\nof hysteresis but also enhancement of current in output characteristics. In addition, we investigated\nthe temperature-dependent behaviors of the TFT performance, including intrinsic carrier mobility\nbased on the Y-function method....
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