Innovative 3-D Printing Processing Techniques for Flexible and Wearable Planar Rectennas

This work demonstrates the use of a low-cost, lossy, flexible substrate processed by novel 3-D printing techniques which significantly mitigate its intrinsic losses, thus providing performance comparable to those of traditional substrates. These processing techniques are applied to both microstrip and coplanar waveguide structures; they are first derived theoretically, starting from the electromagnetic theory of modes propagation, then numerically validated by full-wave analysis, and finally experimentally verified. The design of a miniaturized 868 MHz rectenna, adopting a coplanar-fed patch antenna based on the proposed fabrication approach, is presented. By means of nonlinear/electromagnetic co-design, the antenna is directly matched to the rectifier. A 30-dB power range starting from -20 dBm is considered. Direct matching allows to get rid of a dedicated matching network and its associated losses, resulting in a slight efficiency increase and a significant reduction of the overall dimensions. Finally, the 3-Dprinted prototype is presented: the overall rectenna performance proves that design freedom enabled by 3-D printing paves the way to the use of low-cost flexible dielectric materials, even with poor electromagnetic properties, to realize wearable battery-free wireless nodes

Microwave Devices for Wearable Sensors and IoT

The Internet of Things (IoT) paradigm is currently highly demanded in multiple scenarios and in particular plays an important role in solving medical-related challenges. RF and microwave technologies, coupled with wireless energy transfer, are interesting candidates because of their inherent contactless spectrometric capabilities and for the wireless transmission of sensing data. This article reviews some recent achievements in the field of wearable sensors, highlighting the benefits that these solutions introduce in operative contexts, such as indoor localization and microwave sensing. Wireless power transfer is an essential requirement to be fulfilled to allow these sensors to be not only wearable but also compact and lightweight while avoiding bulky batteries. Flexible materials and 3D printing polymers, as well as daily garments, are widely exploited within the presented solutions, allowing comfort and wearability without renouncing the robustness and reliability of the built-in wearable sensor

Modeling and simulation of nuclear hybrid energy systems architectures

The transition toward a low-carbon energy system and the increasing penetration of variable renewable energy (VRE) sources translate into a pressing need for dispatchable and low-carbon power sources. Nuclear hybrid energy systems (NHES) exploit the synergies between nuclear power and other energy sources together with energy storage devices and a variety of electric and non-electric applications. The expected benefits range from a high flexibility being able to supporting an increasing penetration of the VRE while complying with the grid demand and constraints to an increased profitability brought by the production of commodities beyond electricity (e.g., hydrogen, heat, etc.). A dedicated framework must be developed to evaluate different NHES configurations, particularly with regard to the complex interconnections among the tightly coupled components. In this work, illustrative examples of NHES components were selected and modeled with the object-oriented modeling language Modelica and implemented in the Dymola simulation environment. The technologies considered in this study are a Small Modular Reactor (SMR) based on pressurized water technology, a thermal energy storage (TES) system, and an alkaline electrolyzer for hydrogen production. The dynamic models are then collected in a new Modelica library and assembled into a variety of NHES topologies using a plug-and-play approach. The time-dependent behavior of the NHES layout can be simulated under different operational contexts, enabling the monitoring of key process variables, supporting system design, exploring alternative control strategies, and analyzing different scenarios. The NHESs are investigated in two exemplary scenarios – one representing typical load conditions and the other featuring high VRE penetration – in order to demonstrate the viability of the proposed approach as an initial effort toward the development of a holistic framework for analyzing NHES. The dynamic models effectively met the analysis requirements, for instance, by tracking the production of commodities throughout each operational transient, which is an essential result for evaluating the performance of NHES. In this regard, efficiency is adopted as the figure of merit to compare the different NHES architectures, with simulation results indicating significant overall efficiency improvements in NHES incorporating TES and using nuclear heat to drive non-electric applications

An all-in-one dual band blade antenna for ads-b and 5g communications in uav assisted wireless networks

This paper is aimed at the characterization and manufacturing of an SMA coaxial fed com-pact blade antenna with dual frequency characteristics for broadband applications on board of Unmanned Air Vehicles (UAVs). This antenna is linearly polarized, and it combines the benefits of Automatic Dependent Surveillance-Broadcast (ADS-B) and 5th Generation (5G) communications in one single element, covering both the 1.030–1.090 GHz and the 3.4–3.8 GHz bands thanks to a bent side and a ‘C’ shaped slot within the radiation element. Starting from the simulation outcomes on an ideal ground plane, the results are here extended to a bent ground plane and on two UAV com-mercial CAD models. Details of manufacturing of the antenna in both aluminium and FR-4 substrate materials are presented. The comparison between measurements and simulations is discussed in terms of return loss, bandwidth, gain, and radiation pattern. Results show an antenna with a low profile and a simple structure that can be employed in various wideband communication systems, suiting future UAV assisted 5G networks while being perfectly compliant with forthcoming ADS-B based Detect-And-Avoid (DAA) technologies in Unmanned Aerial Traffic Management (UTM)

Improvement in the removal of micropollutants at Porto Marghera industrial wastewaters treatment plant by MBR technology.

This paper deals with the case of one of the most important industrial application of membrane technology in the world: the upgrading of the main industrial wastewater treatment plant (WWTP) of the petrochemical site of Porto Marghera, Northern Italy, completed on December 2005 and tested on September 2006. It describes the principal interventions of the plant upgrading and it discusses the removal obtained during the test periods for conventional pollutants as well as for micropollutants. The plant upgrading consisted of a series of improvements of the existing industrial WWTP, in order to increase the removal efficiency of the total suspended solids and the associate removal of ten micropollutant compounds, the so called forbidden substances. The most important intervention was the conversion of the existing activated sludge section into a membrane biological reactor, in order to guarantee adherence to the severe limits imposed by the special law issued to protect the Venice Lagoon, with particular reference to the mentioned 10 forbidden compounds. The experimental results and the numerous test-runs conducted confirmed the respect of the legal limits for the pollutants in the final effluent as well of the required removal rates for the different parameters. Therefore, the upgraded treatment plant was declared agreeing with the approved design