The development of contemporary complex technological systems prerequisites interdisciplinary design and simulation methodologies. Such an approach is demonstrated in the present work. Toward manufacturing a hand-held device aiming at internal body temperature measurements using passive microwave radiometer technology, five design and simulation perspectives are elaborated. The proposed system consists of an ultra-wide-band microwave compact antenna, a multi-frequency microwave radiometer, and a digital processing unit, all enclosed in a portable arrangement. A modeling and visualization software, processes acquired measurements according to a predefined model of human breast. The system's concept of operation is based on the fact that a malignant tumor turns out to local temperature increase inside the tissue. By measuring this temperature in successive depths, using different frequency bands in the region of 1-4 GHz, as well as in nearby spatially arranged spots on the human tissue surface, 2-D and 3-D imaging of the temperature distribution are realized. This paper focuses on design and simulation approaches of all system's aspects.

The new generation of wireless communication technologies is already in development. Sixth Generation (6G) mobile communications are designed to push the limits for more bandwidth, more connected devices with minimal power requirements, and better signal quality. Previous technologies used in Fifth Generation (5G) are inadequate to handle the new requirements alone. One of the proposed solutions is the use of Reconfigurable Intelligent Surfaces (RISs). These surfaces, when combined with Artificial Intelligence (AI), may be a very powerful means of achieving this. In this paper, we review studies that focus on the use of RISs controlled by AI in determining the concept of Smart Radio Environment (SRE) for use in 6G wireless networks. We examine applications that span from Supervised to Federated Learning (FL) as enabled by the rise in Edge Computing. As the new generation of mobile devices is expected to have enhanced capabilities to perform computing and AI locally, thus reducing the need to transfer the data to a central hub, more opportunities are created for the extensive use of FL. In this context, we focus on research in FL as used in RIS-aided SRE.

Satellites and spacecraft subsystems in general are vulnerable in terms of electromagnetic interference. Shielded cables, connecting these subsystems as well as the subsystems themselves, are major sources of electromagnetic (EM) emission. The minimization of these emissions is critical in order to achieve EM cleanliness. An accurate model predicting these emissions could offer great insight and enable interference minimization. In this study, a shielded cable model for predicting EM emission via decomposition of contributing phenomena is presented including the ground dielectric properties. The model is built based on a standardized measurement setup and validated for different cases of ground material and cable's position.

Biochar and biochar-based composites are multi-functional materials with a wide range of environmental and other applications. A new and emerging application is in the field of modern communication systems as materials with significant electromagnetic shielding effectiveness. In this study, biochar was prepared from olive tree prunings which was subsequently used at various dosages to prepare composite samples with carbon black and polytetrafluoroethylene as binder. The electromagnetic shielding effectiveness of the samples were measured in the frequency range of 1-3 GHz, using a simple, user-friendly and reliable experimental set-up. The results showed that raw, unmodified biochar had a low shielding effectiveness in the range of 1.5-4 dB however, it slightly increased as the thickness of the sample increased from 0.1 to 0.5 mm. Modifying biochar with the 20 %w/w acetylene black largely increased its shielding effectiveness, reaching the value of 39 dB in the same frequency range. Our approach demonstrated that raw biochar can be used as a substrate to develop composite materials with significant shielding effectiveness and assess their performance with a quick and simple laboratory method.

This study aimed to estimate the radiofrequency exposure levels in the vicinity of nursery and primary schools at the northwest part of Crete island in Greece. Moreover, the compliance with the exposure limits, according to Greek legislation, was investigated. A total of 396 in situ frequency-selective and broadband measurements were conducted around 69 schools, classified in urban and suburban environments, in the range of 27–3000 MHz (subdivided in seven frequency bands). The measured value of the electric field strength (V/m) was recorded and, subsequently, the exposure ratio was calculated. Statistical analysis was performed in order to analyze and evaluate the data. In addition, a worst-case scenario was examined by considering the highest measured exposure level around each school. The statistical tests indicated that the mean and median values of the exposure ratio, even in the worst-case scenario, were found well below 1 for all frequency bands. The calculated distributions of the electric field measurements demonstrated that almost 90% of the latter were below 1 V/m, with the majority of values lying in the range of 0.5–1 V/m. The main contributors to the total exposure were the mobile communication frequencies and broadcasting, while the exposure was greater in urban than in suburban environments.

A textile, embroidered antenna, based on the fractal shape of the Sierpinski triangle, is designed in this paper for operation in the European free Industrial Scientific and Medical (ISM) 863–870 MHz band, as well as in the 902–928 MHz band designated for ISM applications in North and South America. Several prototypes have been fabricated by employing different stitch patterns and thread materials. The effect of the fabrication parameters on the performance of the proposed antenna is investigated through measurements and simulations, with the results being in good agreement. The antenna exhibits attractive characteristics such as wide bandwidth, relatively stable radiation patterns, as well as robustness in washing. Several tests reveal that convex and concave bent conditions do not affect the coverage of the aforementioned ISM bands, despite the shift of the resonant frequency in some cases. Moreover, the SAR values resulting from simulations are below the corresponding thresholds suggested by international guidelines.