In modern-day photonic integrated circuits, near-field Coulomb interaction plays an important role in device performance. In fact, harvesting the Coulomb effect intelligently can immensely help to realize advanced photonic devices on micro and nano length scales. In this context, electrically coupled terahertz metasurfaces are investigated for weak and strong near-field coupling regimes under the influence of variable photoexcitation. Our study demonstrates active tuning of metasurface resonances at relatively low pump powers (up to 10 mW (pump fluence of 12.7 µ J cm ⁻² ) and 20 mW (pump fluence of 25.4 µ J cm ⁻² ) for strong and weak near-field coupling regimes, respectively). We attribute photoinduced modifications of substrate electronic properties along with modifications of near-field interactions to be responsible for the resonance modulations. Furthermore, we demonstrate that the Coulomb effect parameter can be dynamically tunable with variable pump power. Our study reveals that the change in Coulomb parameter is more pronounced for the weak near-field coupling regime (more than six times enhancement in Coulomb parameter) in comparison to the strong near-field coupling regime. In addition, the optical switching of the fundamental resonance is validated utilizing numerically simulated patterns of surface current and electric field. We envisage that such active modulation of Coulomb effects in near-field coupled metasurfaces can lead to the realization of dynamically tunable terahertz metaphotonic devices.

Many factors are influencing the acceptability of energy technology. The transformation of the energy sector is looking for clean energy technology that is also suitable for baseload power generation. Terrestrial solar energy has many obstructions, so solar power from space without any hindrance has higher priority for adoption, and it is suitable for future energy continuous demand supply. As technology is advancing, the possibility of satellite solar-based power station is more than a science fiction now and is possible in the coming future. Microwave transmission with high beam efficiency is the key issue to be improved for the feasibility of satellite solar power station. Besides others, research should focus on the reduction of space segment’s components dimension and space vehicle dispatch cost. Concerning space segments, applying an optimized value of fractional power unit modules and assembling it for constant baseload power supply have economic advantages, as well as that the antenna size is also reduced. This work deals with system components size estimation and optimization for a selected 10-GW baseload power supply. Four case studies have been conducted considering the different unit sizes, and the system model is analyzed for suitable power unit selection.

In this article, the concept of a 22-kW microwave-powered unmanned aerial vehicle is presented. Its system architecture is analyzed and modeled for wirelessly transferring microwave power to the flying UAVs. The microwave system transmitting power at a 35 GHz frequency was found to be suitable for low-cost and compact architectures. The size of the transmitting and receiving systems are optimized to 108 m² and 90 m², respectively. A linearly polarized 4 × 2 rectangular microstrip patch antenna array has been designed and simulated to obtain a high gain, high directivity, and high efficiency in order to satisfy the power transfer requirements. The numerically simulated gain, directivity, and efficiency of the proposed patch antenna array are 13.4 dBi, 14 dBi, and 85%, respectively. Finally, a rectifying system (rectenna) is optimized using the Agilent advanced design system (ADS) software as a microwave power receiving system. The proposed rectenna at the core of the system has an efficiency profile of more than 80% for an RF input power range of 9 to 18 dBm. Moreover, the RF-to-DC conversion efficiency and DC output voltage of the proposed rectenna are 80% and 3.5 V, respectively, for a 10 dBm input power at 35 GHz with a load of 1500 Ω.

This work presents an enhanced rectenna with differentially fed antenna array for RF energy harvesting. First, a linear antenna array is designed considering its side lobes less than −20 dB. Two antenna array, one with a single feed and other with differential feed, is designed to operate at 5.8 GHz. The measured peak gain of single fed and differentially fed is 13.38 and 14.29 dBi, respectively, at 5.8 GHz. The two antenna array, one with a single feed and other with differential feed, is tested for RF energy harvesting. It is observed that the differentially fed rectenna has higher output DC power than the single fed rectenna. The differentially fed rectenna has higher efficiency as compared with single fed rectenna for the power density variation from 5 to 238 µW/cm², it has maximum efficiency (RF-DC) of 82.4% at 232 µW/cm².

There are some limitations during the interconnection of fuel cells (FCs) to the utility grid. The output voltage of fuel cell is low and unregulated DC. It should be boosted and inverted before connecting to the grid. Because of the slow response time of chemical processes in FCs, a suitable power conversion unit is needed which improves the dynamic response of the system during interconnection with the utility grid. In this work, a model of 50kW solid oxide fuel cell (SOFC) system with DC-DC boost converter and DC-AC inverter has been presented. The response of the system has been analysed through simulation results. Simulation results show the improvement in the response and validate proposal of SOFC system for grid integration.