This paper reviews the state of emerging transistor technologies capable of terahertz amplification, as well as the state of transistor modeling as required in terahertz electronic circuit research. Commercial terahertz radar sensors of today are being built using bulky and expensive technologies such as Schottky diode detectors and lasers, as well as using some emerging detection methods. Meanwhile, a considerable amount of research effort has recently been invested in process development and modeling of transistor technologies capable of amplifying in the terahertz band. Indium phosphide (InP) transistors have been able to reach maximum oscillation frequency (fmax) values of over 1 THz for around a decade already, while silicon-germanium bipolar complementary metal-oxide semiconductor (BiCMOS) compatible heterojunction bipolar transistors have only recently crossed the fmax = 0.7 THz mark. While it seems that the InP technology could be the ultimate terahertz technology, according to the fmax and related metrics, the BiCMOS technology has the added advantage of lower cost and supporting a wider set of integrated component types. BiCMOS can thus be seen as an enabling factor for re-engineering of complete terahertz radar systems, for the first time fabricated as miniaturized monolithic integrated circuits. Rapid commercial deployment of monolithic terahertz radar chips, furthermore, depends on the accuracy of transistor modeling at these frequencies. Considerations such as fabrication and modeling of passives and antennas, as well as packaging of complete systems, are closely related to the two main contributions of this paper and are also reviewed here. Finally, this paper probes active terahertz circuits that have already been reported and that have the potential to be deployed in a re-engineered terahertz radar sensor system and attempts to predict future directions in re-engineering of monolithic radar sensors.

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Over the last decade, manufacturing processes have undergone significant change. Most factory activities have been transformed through a set of features built into a smart manufacturing framework. The tools brought to bear by the fourth industrial revolution are critical enablers of such change and progress. This review article describes the series of industrial revolutions and explores traditional manufacturing before presenting various enabling technologies. Insights are offered regarding traditional manufacturing lines where some enabling technologies have been included. The manufacturing supply chain is envisaged as enhancing the enabling technologies of Industry 4.0 through their integration. A systematic literature review is undertaken to evaluate each enabling technology and the manufacturing supply chain and to provide some theoretical synthesis. Similarly, obstacles are listed that must be overcome before a complete shift to smart manufacturing is possible. A brief discussion maps out how the fourth industrial revolution has led to novel manufacturing technologies. Likewise, a review of the fifth industrial revolution is given, and the justification for this development is presented.

The increasing popularity of electric vehicles (EVs) has been attributed to their low-carbon and environmentally friendly attributes. Extensive research has been undertaken in view of the depletion of fossil fuels, changes in climatic conditions due to air pollution, and the goal of developing EVs capable of matching or exceeding the performance of today’s internal combustion engines (ICEs). The transition from ICE vehicles to EVs can reduce greenhouse gases significantly over a vehicle’s lifetime. Across the different types of EVs, the widespread usage of batteries is due to their high power density and steady output voltage, making them an excellent energy storage device (ESD). The current downsides of battery-powered electric vehicles include long recharge times, the impact of additional strain on the grid, poor societal acceptance due to high initial costs, and a lack of adequate charging infrastructure. Even more problematic is their short driving range when compared to standard ICE and fuel cell EVs. Battery degradation occurs when the capacity of a battery degrades, resulting in a reduction in travel range. This review article includes a description of battery degradation, degradation mechanisms, and types of degradation. A detailed investigation of the methods used to address and reduce battery degeneration is presented. Finally, some future orientation in terms of EV research is offered as vital guidance for academic and industrial partners.

The Smart Sensors, Measurement and Instrumentation series (SSMI) publishes new developments and advancements in the fields of Sensors, Instrumentation and Measurement technologies. The series focuses on all aspects of design, development, implementation, operation and applications of intelligent and smart sensors, sensor network, instrumentation and measurement methodologies. The intent is to cover all the technical contents, applications, and multidisciplinary aspects of the field, embedded in the areas of Electrical and Electronic Engineering, Robotics, Control, Mechatronics, Mechanical Engineering, Computer Science, and Life Sciences, as well as the methodologies behind them. Within the scope of the series are monographs, lecture notes, selected contributions from specialized conferences and workshops, special contribution from international experts, as well as selected Ph.D. theses.