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Realistic human exposures to radiation emitted by a mobile terminal connected to either a 5G network (sub-6 GHz) or to a 4G network have been scarcely assessed till now. Present experimental work aimed at comparing the radiated field in air, in a single point situated at 10 cm from a mobile phone when running a set of 5 mobile applications in the two communication standards. The time-evolution of the electric field strength in air near the terminal during 25 s of use was recorded by an original method, together with the data rate of transmission. The emitted power density dynamics, its statistics, its slope of accumulation after the usage period and its average value per transmitted bit are analyzed and compared between all the situations. The peculiarities are emphasized and they are proved to depend on the communication standard and on the mobile application.

To gain a deeper understanding of the hotly contested topic of the non-thermal biological effects of microwaves, new metrics and methodologies need to be adopted. The direction proposed in the current work, which includes peak exposure analysis and not just time-averaged analysis, aligns well with this objective. The proposed methodology is not intended to facilitate a comparison of the general characteristics between 4G and 5G mobile communication signals. Instead, its purpose is to provide a means for analyzing specific real-life exposure conditions that may vary based on multiple parameters. A differentiation based on amplitude-time features of the 4G versus 5G signals is followed, with the aim of describing the peculiarities of a user’s exposure when he runs four types of mobile applications on his mobile phone on either of the two mobile networks. To achieve the goals, we used signal and spectrum analyzers with adequate real-time analysis bandwidths and statistical descriptions provided by the amplitude probability density (APD) function, the complementary cumulative distribution function (CCDF), channel power measurements, and recorded spectrogram databases. We compared the exposimetric descriptors of emissions specific to file download, file upload, Internet video streaming, and video call usage in both 4G and 5G networks based on the specific modulation and coding schemes. The highest and lowest electric field strengths measured in the air at a 10 cm distance from the phone during emissions are indicated. The power distribution functions with the highest prevalence are highlighted and commented on. Afterwards, the capability of a convolutional neural network that belongs to the family of single-shot detectors is proven to recognize and classify the emissions with a very high degree of accuracy, enabling traceability of the dynamics of human exposure.

The paper presents the design and implementation of an electromagnetic field monitoring sensor for the measurement of the Terrestrial Truncked Radio (TETRA) signals using low-cost software defined radio (SDR) platforms. The sensor includes: an SDR platform, a Global Positioning System (GPS) module and a hardware control module. Several SDR platforms having different resolutions of the analog–digital converters were tested in the first phase. The control module was implemented in two variants: a fixed one, using a laptop, and a mobile one, using a Raspberry Pi. The tests demonstrate the following achieved performances: instantaneous acquisition band of 5.12 MHz; dynamic range of the input signal level of (−100 to −30) dBm; frequency resolution of 2.5 kHz; portability and flexibility for use in outdoor environments. The sensor allows complete reporting through amplitude-time-frequency-location descriptors, and in the case of the mobile version, the system performs correctly even at a maximum speed of displacement of 120 km/h. The price of the mobile sensor system variant is approximately EUR 320.

Microwaves have been frequently applied for extraction of bioactive compounds of different origin, using systems operating at 200 -1000 W power, the efficiency being related to the heating of molecules. This study investigated the effects of non-thermal microwaves at 1.7 and 2.5 GHz for different exposure time, on the phenolic content and antioxidant activity of Boletus edulis extracts. The irradiated mixtures of fresh samples in ethanol solution showed increased phenolic content compared to control and in contrast to those of dried samples. The ATR-FTIR analysis indicates no structural changes after irradiation, confirming that the effect is due to the cell membrane disruption facilitating the compounds’ release. The antioxidant activity of extracts from fresh samples significantly increased after MW exposure at 1.7 GHz for 3 h, 775 Vm-1. These results suggest that microwaves at investigated frequencies and electric field strengths can contribute to an efficient extraction of antioxidants from fresh mushrooms.