In a pandemic, the availability of health indicators among at-risk populations, such as the elderly, is vital due to the disease’s rapid transmission and the need to act quickly to contain its evolution. Traditional clinical methods for monitoring vital signs typically require contact-based sensors that must be precisely attached by a skilled healthcare professional, are less practical for repeatable measurements, and are not suitable for long-term monitoring. Contactless vital signs monitoring, such as radar-based techniques or IR-thermal imaging, on the other hand, does not require the attachment of physical electrodes and can be useful for remote health monitoring and therefore reduce physical contact between subjects and healthcare professionals, ensuring social distancing, in particular, in nursing homes, and protecting the elderly population in this way from other external factors that increase the likelihood of infection. This article presents three main contributions: (i) vital signs characterization in the elderly population; (ii) a state-of-the-art review on the most prominent techniques and methods for Contactless Health Monitoring (CHM); (iii) the design, specification, and evaluation of a low-cost proof-of-concept CHM system for nursing homes, which includes an IoT Edge Device , which enables real-time vital signs monitoring (cardio-respiratory rates and elevated body temperature) using a multimodal approach based on Doppler radar and IR thermal imaging sensors, and thus generates health indicators without any type of contact or invasiveness. By direct comparison with reference instruments, results have shown an error below 10%, in 74%, 52%, and 96% of the cases for Heart Rate, Respiratory Rate, and Body Temperature measurements, respectively.

As wireless communication technology advances towards faster and higher transmission rates such as Fifth Generation (5G) and beyond, the need for multiple access points increases. The growing demand for access points often results in them occupying any available surface area and potentially disrupting the existing scenery. In order to address this issue, Optically Transparent Antennas (OTAs) emerge as an optimal solution for balancing the aesthetics of a specific setting with the desired communication system requirements. These antennas can be integrated into various infrastructures without interfering with the design of the objects on which they are installed. Research on the techniques and materials for OTA fabrication, which is proposed as a solution to the 5G wireless communication demand for access points, is presented. This work will highlight key antenna characteristics such as gain, bandwidth, efficiency, and transparency, and how the materials used for OTA implementation influence these parameters. Techniques like Metal Mesh (MM), Transparent Conductive Film (TCF), and Transparent Conductive Oxide (TCO) will be explained. The performance of the OTAs will be analyzed based on gain, bandwidth, transparency, and efficiency. This paper also addresses the challenges and limitations associated with OTAs. Finally, it confirms that OTAs offer a compelling solution for this scenario by balancing aesthetics with high antenna performance, making them an innovation for future wireless networks.

Unmanned Aerial Vehicles (UAVs), commonly known as drones, are becoming increasingly important in multiple areas and various applications, including communication, detection, and monitoring. This review paper examines the development of antennas for UAVs, with a particular focus on miniaturization techniques, polarization strategies, and beamforming solutions. It explores both structural and material-based methods, such as meander lines, slots, high-dielectric substrates, and metasurfaces, which aim to make the antenna more compact without compromising performance. Different antenna types including dipole, monopole, horn, vivaldi, and microstrip patch are explored to identify solutions that meet performance standards while respecting UAV constraints. In terms of polarization strategies, these are often implemented in the feeding network to achieve linear or circular polarization, and beamforming techniques like beam-steering and beam-switching enhance communication efficiency by improving signal directionality. Future research should focus on more lightweight, structurally integrated, and reconfigurable apertures that push miniaturization through conformal substrates and programmable metasurfaces, extending efficient operation from 5/6 GHz into the sub-THz regime and supporting agile beamforming for dense UAV swarms.

The rise in popularity of the Internet of Things (IoT) has increased the need to power devices wirelessly, a process called Wireless Power Transfer (WPT), to avoid the usage of batteries, which present limited lifespans. In particular, Microwave Power Transfer (MPT), both Near-field (NF) and Far-field (FF), use Electromagnetic (EM) waves to transfer power between two points. However, these systems still present some downsides, mainly efficiency-wise. This paper explores the usage of Multibeam Antennas (MBAs), specifically Beamforming Network (BFN)-based ones, to improve the capabilities of traditional MPT and Radio Frequency Energy Harvesting (RFEH) systems. The paper starts by introducing the usage of MPT in IoT applications and how MBAs could help solve some of them or at least mitigate them. Afterward, a general explanation of the typical MBAs architectures, including Passive Multibeam Antennas (PMBAs), Multibeam Phased-Array Antennas (MBPAAs), and Digital Multibeam Antennas (DMBAs) is presented, along with their advantages, drawbacks, and some emerging trends. After introducing the typical architectures of MBAs, a comprehensive literature survey is done around rectennas and MPT Transmitters (TXs). This approach allows us to understand better why some architectures are more present than others in both applications, highlighting the exclusive usage of PMBAs in rectennas due to them not using energy. To finalize the paper, using the literature survey done, some challenges associated with integrating MBAs in MPT and RFEH are presented, along with some works presenting ways to mitigate them.