In this paper, various ambient energy-harvesting technologies (solar, thermal, wireless, and piezoelectric) are reviewed in detail and their applicability in the development of self-sustaining wireless platforms is discussed. Specifically, far-field low-power-density energy-harvesting technology is thoroughly investigated and a benchmarking prototype of an embedded microcontroller-enabled sensor platform has been successfully powered by an ambient ultrahigh-frequency (UHF) digital TV signal (512-566 MHz) where a broadcasting antenna is 6.3 km away from the proposed wireless energy-harvesting device. A high-efficiency dual-band ambient energy harvester at 915 MHz and 2.45 GHz and an energy harvester for on-body application at 460 MHz are also presented to verify the capabilities of ambient UHF/RF energy harvesting as an enabling technology for Internet of Things and smart skins applications.

A compact dual-band rectenna operating at 915 MHz and 2.45 GHz is presented. The rectenna consists of a slot-loaded dual-band folded dipole antenna and a dual-band rectifier. The length of the proposed antenna is only 36.6% of the half-wavelength (λ₀/2) dipole antenna at 915 MHz while keeping dual-band property at 915 MHz and 2.45 GHz. The rectifier circuit is optimized for low input power densities using harmonic balance (HB) simulation. The efficiencies of the rectifier are evaluated with both single- and dual-frequency input signals. The measured results show an efficiency of 37% and 30% at 915 MHz and at 2.45 GHz when illuminated by a microwave signal of available power of -9 dBm for a load resistor of 2.2 k Ω.

In this work, the concept of dual-band resistance compression networks is introduced and applied to the design of rectifier circuits with improved performance. The use of resistance compression networks (RCNs) minimizes the sensitivity of rectifier circuits to variations in the surrounding environment, such as input power level and changes in the rectifier load. The proposed dual-band RCN can be used as the matching network located between the antenna and the rectifying element of a dual-band rectifier for energy harvesting applications. A dual-band ( 915 MHz /2.45 GHz) rectifier based on RCN is designed and characterized showing improved performance in comparison with a conventional dual-band envelope detector by exhibiting improved RF-dc conversion efficiency and reduced sensitivity versus output load and input power variations.

Radio frequency (RF) energy harvesting and wireless power transmission (WPT) technologies —both near-field and far-field—have attracted significant interest for wireless applications and RFID systems. We already utilize near-field WPT products in our life and it is expected that RF EH and far-field WPT systems can drive the future low-power wireless systems. In this article, we initially present a brief historical overview of these technologies. The main technical challenges of rectennas and WPT transmitters are discussed. Furthermore, this paper presents the recent advances on the development of these technologies, including the possibility of powering RFID systems through the millimeter wave power from 5G networks, the trends in flexible rectennas design and the technological developments on the simultaneous wireless information and power transfer (SWIPT).

This paper presents a review of existing works and solutions in the field of solar/electromagnetic energy harvesting and wireless power transmission. More specifically, the paper covers: solar/electromagnetic harvesters where solar antenna structures are used to obtain a compact implementation, direct current (dc) combining circuits necessary to combine the outputs of the solar and the electromagnetic harvesters, and efficient solar-to-electromagnetic (EM) converters that can be used to synthesize autonomous wireless power transmission radio-frequency (RF) signal generators. Finally, novel topologies to minimize the sensitivity of rectifier circuits to variations in the received RF power levels are presented.

Current technology and especially Artificial Intelligence effectively increase productivity and take cost out of operations in the Manufacturing sector. One of the main representatives of information technology in the industrial applications are agents. This paper suggests a way to a) categorize multi-agent systems according to the coordination mode among agents and b) classify agents that take action on them, depending on their functions It examines the main approaches of multi-agent architectures, according to their coordination way. The main coordination types are: a) centralized multi-agent coordination (or coordinator agents), in which one central agent undertakes the collection of partial plans from agents, combines them in a plan and solves possible conflicts and b) decentralized multi-agent coordination (or autonomous agents), in which agents are not controlled by a central agent although they communicate with each other for the creation of their plans and the solution of possible arguments. Although there are several aspects that we can consider in order to classify CAD, CAPP and CAM multi-agent systems, this review develops a classification scheme, based on interaction characteristics