BackgroundTraditional subspace methods like SS-MUSIC often degrade under low sample support. This is further exacerbated by strong mutual coupling within antenna arrays. While deep learning offers a potential alternative, standard architectures often operate as “black boxes,” lacking the physical interpretability and mathematical rigor required for electromagnetic modeling.MethodsThis paper proposes a novel Hybrid Graph Neural Network combined with a Deep Unrolling (LISTA-style) architecture. We map the Sample Covariance Matrix (SCM) onto a graph representation and utilize a shared spatial kernel (S-matrix) to maintain physical consistency across a 12-element Uniform Linear Array To resolve artifacts, we introduce a specialized “Ghost-Killer” loss function that penalizes false peaks through a quartic penalty term. The model utilizes layer-wise scalar modulators gamma (γ) and lambda (λ) to provide an interpretable “denoising curriculum.”ResultsExperimental results demonstrate that the proposed model achieves a peak success rate of 98.0% at high SNR. Crucially, the model provides super-resolution capabilities, resolving sources at a 3.0° separation with ∼70% accuracy, significantly outperforming SS-MUSIC (∼36%). Furthermore, architecture exhibits high robustness to “sample starvation,” maintaining a 78.0% success rate at only 50 snapshots, a +14% improvement over classical methods.ConclusionThe convergence of graph-based spatial reasoning and deep Unrolling provides a robust, interpretable framework for high-fidelity antenna array calibration and signal reconstruction, directly supporting the advancement of real-time electromagnetic diagnostics in industrial and decentralized environments.
The objective of this manuscript is to analyze and electromagnetically simulate two different horn antenna configurations, namely, a pyramidal horn antenna and a conical horn antenna. Both antennas are considered as radiating elements in a satellite communication system operating within the X-band frequency range of approximately 8–12GHz. The geometric parameters were determined analytically through mathematical calculations performed in Matlab and subsequently validated using two electromagnetic simulation environments, Ansys HFSS and CST Studio Suite. This approach enabled the evaluation of the performance of each antenna configuration as well as the assessment of their corresponding geometric structures. For the pyramidal horn antenna, fed by a WR-90 rectangular waveguide, the simulation results demonstrate good impedance matching across the X-band (S11 = −10dB). The minimum reflection coefficient values obtained are S11 = −39.43dB at 8.22 GHz in HFSS and S11 = −56.18dB at 8.07 GHz in CST Studio Suite. The antenna exhibits a maximum gain of 23.63dB with a narrow half-power beamwidth of approximately 6°–10°, confirming its high directivity and efficient electromagentic radiation. For the conical horn antenna, fed by a BY89 circular waveguide, the simulation results confirm good impedance matching over the 9–12 GHz frequency range, with the reflection coefficient (S11) remaining below −10dB throughout the entire bandwidth. The minimum reflection coefficient values are S11 = −43 dB at 11.22 GHz in HFSS and S11 = −39.70 dB in CST Studio Suite. The antenna exhibits a maximum gain of 16.43 dB and a half-power beamwidth (HPBW) of approximately 30°, which is suitable for satellite communication antennas. Circular polarization was obtained through bimodal excitation of two orthogonal TE11 modes. An Axial Ratio AR<3dB was achieved within the main lobe region. A comparative of the two antenna configurations shows that the pyramidal horn antenna provides a higher gain and narrower beamwidth, characteristics that are suitable for applications requiring high directivity and linear polarization. The conical horn antenna demonstrates significant advantages for satellite applications due to its geometric symmetry, wider beamwidth, which is appropriate for reflector illumination, and support circular polarization through its symmetrical geometry. These characteristics make it suitable for satellite communication systems operating with circularly polarized waves. In additional, the conical horn antenna represents the basic geometric configuration from which the conical corrugated horn antenna is derived. The results obtained for this structure therefore provide a reference for the analysis and design of corrugated horn antennas in future work. The results obtained using Ansys HFSS and CST Studio Suite are in good agreement, with only minor differences observed between the two simulation environments. This consistency indicates that the antenna designs and the corresponding simulation models are suitable for X-band satellite communication applications.
A novel Cylindrical Dielectric Resonator Antenna (CDRA) with a unique shape, powered by a modified microstrip line, is examined in this article to achieve multiband operation. A flipped ‘F’ type microstripline is used to excite the proposed CDRA, which serves as a magnificent frequency tuner for improving bandwidth in all the three available bands. The proposed design is very simple and low profile, having a thickness of only 2.5 mm and is highly desirable in wireless local area network (WLAN) frequency bands such as 5.470–5.725, 5.725–5.850, and 5.9 GHz bands. This design produces three distinct bands with bandwidths of 18.57% for the lower band, 9.9% for the middle band, and 15.8% for the upper band. Since it works both in C and X band, it can be used as a satellite antenna and is best suitable for air traffic control, weather monitoring, vehicle speed detection, defense tracking and RADAR applications. The cylindrical DR structure with a moderate dielectric constant of 10.2, with flipped ‘F' type microstrip feeding, generates HEM modes that lead to triple bands and an enlarged bandwidth. The proposed antenna was fabricated, measured and correlated with some of multiband DRAs mentioned in the references. The results show a strong correlation between simulated and measured outcomes, demonstrating good overall performance regarding radiation efficiency, gain, and bandwidth.
Increased focus on secure communications has created a growing interest in national and regional satellite systems. An elliptic medium earth orbit satellite system for Nordic/Arctic areas is proposed and investigated. Three satellites in a single orbital plane will provide continuous coverage. New technology, digitizing radio signals at radio frequency (RF), digital phased-array antenna steering and digital combining of multiple antenna panels make efficient and low-cost implementation of high-performance user terminals possible. The satellite orbits are simulated to define the distribution of elevation, azimuth, and variation of path distances for sites in the focus area. The distributions are input to a performance analysis of the user terminal antenna solution. For the S-band, an electronically steered multipaneled antenna, denoted as a five-panel frustum configuration, is proposed and analyzed for fixed-site installations and installations on a moving ship. With a panel size of 20 cm × 20 cm, the antenna is compact, small, and has room for four antenna elements at 2 GHz. The configuration shows good performance for all satellite azimuths and elevations. In this concept, one antenna panel of five is active, the maximum scan loss is 1.2 dB, and the total gain, including element gain, array gain, and losses, is estimated to be ≈ 9–12 dBi in practical implementation. In an advanced concept, co-phasing and combining 3–5 simultaneously active panels, there is a potential for a gain increase to ≈14−17 dBi. Analysis shows excellent robustness against angular movements on a ship’s platform up to a tilt of 10°. Important propagation issues related to ship-to-satellite communication, such as ionospheric attenuation, scintillations, reflections, and scattering from the sea surface, are analyzed. Comprehensive link budgets for both VHF and S-band are provided, along with the potential information rates for each option. These are 9.6 kbit/sec for a handheld VHF user terminal with an omni antenna, and 1024 kbit/sec for S-band with a frustum-configured, four-element phased-array antenna. The link margin is 4–5 dB, allowing for interference and variation in distance to the satellite.
IntroductionAssessment of incident power density (IPD) for radiating antennas using conventional equal-angle spherical sampling leads to redundant measurement points and reduced efficiency.MethodsThis study introduces a non-redundant uniform spherical sampling method for assessing IPD in radiating antennas, implemented using spiral-based and particle-based sampling schemes. The proposed approach is validated using a K-band rectangular horn antenna operating at 18 GHz. Its performance is compared with conventional equal-angle sampling in terms of far-field patterns, peak IPD components, and 4-cm2 averaged IPD over source‐observation distances ranging from 300 to 1,000 mm.ResultsThe proposed non-redundant sampling method produces far-field patterns that are nearly identical to those obtained using equal-angle sampling. The discrepancies in peak IPD components and their 4-cm2 averaged values are less than 0.17 dB across all evaluated distances. The number of measurement points is reduced by approximately 40%.DiscussionThe results demonstrate that the proposed method significantly improves measurement efficiency while preserving high accuracy in IPD assessment and antenna far-field characterization, providing a practical and reliable solution for antenna measurements and electromagnetic field safety assessments.
The structural health monitoring (SHM) of wind turbine blades is crucial for early failure identification, which subsequently reduces maintenance costs and ensures reliable operation in both onshore and offshore environments. Radio frequency (RF) and microwave radar technologies offer an effective non-contact and weather-resistant method for assessing wind turbine blade deflection. To achieve high-performance radar, various antenna types are offered in the literature, each with specific requirements and methodologies aimed at enhancing their performance to improve radar detection accuracy, such as high gain and narrow beam width. Among the different Doppler radars, Frequency Modulated Continuous Wave (FMCW) radar is preferred due to its enhanced spatial resolution, phase-based displacement sensitivity, and accurate fault localization. Additionally, radar performance can improve using advanced digital signal processing (DSP), improving signal strength, detection accuracy, and mitigating the multipath interference effect. This study examines RF-based solutions for wind turbine blade deflections, addressing various types of antennas, their placement on the blade at distinct frequencies (e.g., UWB and mmWave). It also tackles the primary limits of monitoring, including air attenuation, multipath effects, and resolution constraints. Challenges and future work for wind turbine monitoring based on RF were also mentioned. This overview establishes the fundamentals for the RF-based strategy in SHM of wind turbine blades.
A new design for a reconfigurable polarizer integrated E band horn antenna is proposed in this paper. The reconfigurable polarizer consists of two septum based waveguides which can be arranged in different configurations. Depending on the orientation of the waveguides relative to each other the desired polarization can be achieved among Linear, Right-handed circular and Left-handed circular polarization. The polarizer is integrated with a horn antenna and optimized to work from 60 to 90 GHz. This antenna is fabricated, and measured for different frequencies. The proposed design has a line of sight Axial Ratio (AR) around 1 dB and a 3 dB AR beamwidth of 56O at the center frequency.
Over the past decade, sensors for skin cancer detection, with operation at micro- and millimeter-wave frequency range, have been under investigation. Thus, safety concerns related to radiation exposure have become critical, especially for patients with vulnerable skin. Studies to date fell short in detailed safety assessments. Many evaluations rely on a single-tissue model representing a single anatomical site. Moreover, most studies assess safety solely via specific absorption rate (SAR) but omit the temperature-rise analysis induced by radiation exposure. In this work, we investigate two types of surface-wave-based antennas operating in the microwave band. Multilayer tissue models were constructed to emulate nine major body sites. The key safety metrics, including the SAR distribution and temperature increase, were analyzed through full-wave electromagnetic simulations in Ansys HFSS. The results reveal substantial inter-site variability in the metrics, highlighting the necessity of full-body evaluation prior to determining the overall safety measures for the new diagnostic devices. Furthermore, we derive power limits for surface-wave antennas in accordance with U.S. and Canadian safety standards, and verify their conservativeness via temperature analysis. Our findings provide a basis for a comprehensive framework for radiation safety assessment of wearable devices operating in the microwave band.
This study presents metamaterial arrays featuring point-symmetric, dimensionally optimized meander-line (ML) complementary split ring resonators (CSRRs) to reduce mutual coupling between closely spaced microstrip patch antennas (MPAs) at a center frequency of 5.8 GHz. The compact nature of these array elements enables reduced form factors for size, weight, and power (SWaP)-constrained applications. This approach is expected to provide improved signal-to-noise ratio and electronic beam steering by accommodating more elements within a fixed area than traditional arrays. Simulations conducted using the Advanced Design System (ADS, Keysight Inc.) assessed the feeding structures for arrays of 4, 16, and 64 elements, while the High-Frequency Structure Simulator (HFSS, ANSYS Inc.) was used to optimize and simulate both the feeding structures and complete arrays to evaluate scalability. The 4-element MMA unit cell has a spacing of 3 mm, which is approximately a 16th (∼λ/16) of the free space wavelength (λ), while reference MPA arrays use a conventional spacing of 25.8 mm (∼λ/2). A comparison reveals that the reduced surface area in MMAs impacts beam patterns and realized gain. Simulations indicate that as the number of elements increases, area reduction reaches nearly 80% for the ideal simulated 64-element case. MMAs offer polarization reconfiguration and adjustable element spacing, giving design flexibility while retaining significant area advantages. To validate the simulations, 2 × 2 and 4 × 4 reference and MMAs were fabricated and characterized. The 8 × 8 designs were not fabricated due to excessive FR4 substrate losses and the complexity of compact feeding structures. Arrays were manufactured by Sunstone Circuits using standard printed circuit board processes, ensuring the simple, accurate, and low-cost fabrication of designs. Characterization by the University of Florida and Rohde and Schwarz confirmed that measurement results closely match simulations, showing MMA size reductions of 76.83% and 77.02% compared to reference arrays, with realized gains of 6.22 dB and 9.38 dB for the 4- and 16-element MMAs, respectively. These MMA architectures are expected to benefit compact wireless RF systems in both the defense and commercial sectors, including radar and communication applications.
This article introduces a planar, highly transmissive, 3-D printable metastructure with a low profile for enhancing the far-field radiation performance of conventional electromagnetic band-gap (EBG) resonator antennas. The proposed near-field phase transforming metastructure (PTM) is developed by employing the near-field phase transformation approach that transforms the non-uniform phase of a conventional EBG resonator antenna into a nearly uniform one and enhances the far-field radiation pattern. The novelty of this paper lies in reducing the height of the phase-transforming structure compared to state-of-the-art structures with better performance. The metastructure’s low profile is realized by incorporating metal inside the dielectric materials. The proposed PTM comprises two types of unit cells made of metal and dielectric material to achieve a wide range of phase coverage. All the phase transforming unit cells used are highly transmitting as their transmission coefficient (|S21|) is greater than −0.77 dB, which increases the aperture efficiency compared to previous designs. Additionally, the proposed metastructure is fully passive and polarization-independent. To achieve the desired performance, the PTM can be realized by using additive manufacturing technologies and exploiting RF-graded 3-D printing filament. The proposed metastructure-based wide-band EBG resonator antenna achieves a peak directivity, aperture efficiency, and 3 dB directivity bandwidth of 21.4 dBi, 54.65%
Human body communication (HBC) utilizes the human body as a medium of communicating data. Considerable research has been done to characterize HBC channels to optimize communication techniques. However, dynamic HBC channels have been less studied. An approach for developing dynamic models of the human body channel for galvanic communication is presented using multiphysics finite element analysis (FEA). An analytical framework is formulated that utilizes stochastic ABCD network parameters to explore and model dynamic HBC channel segments. Channel segments were subjected to mechanical forces using the finite element method (FEM) to reveal their impact on the current density and electric field. Linear regression modeling shows a strong relationship between applied force, current frequency, and channel response, with R² metrics exceeding 0.99. The dynamic nature of the channel reflects the need for stochastic modeling. This study examined candidate probability density functions (PDFs) to describe channel fading for the ABCD network parameters. Lognormal and Weibull distributions fit the magnitudes best while the generalized Pareto, generalized extreme value, and logistic distributions fit the phases best. Empirical modeling validated the accuracy of the lognormal distribution fits found using the FEM. The dynamic channel was characterized utilizing multiphysics FEM modeling, empirical modeling, and ABCD network parameters. This information is invaluable for EM dosimetry analysis and risk assessment in body area network (BAN) device design, as well as device optimization, because stochastic HBC parameters emulate the dynamic nature of the human body channel.
This paper proposes an extension of a ray-tracing based model for radiowave propagation in the presence of vegetation, to account for the wind-induced channel dynamics in vegetated environments. The original propagation model uses various point scatterers with specific re-radiation and it has been proven to be suitable for a wide range of scenarios. However, the swaying motion of the tree branches and leaves, as an effect of the wind, creates a constantly changing environment that influences the propagating radio signals in both amplitude and phase, resulting in signal level fluctuations. A large measurement campaign intending to record and characterize the effect of wind-induced dynamics in vegetated environments, was conducted in a controlled environment, inside an anechoic chamber. Experiments included various wind directions and at varying speeds: stationary (0 m/s), low (1.9 m/s) and high (4.7 m/s). The dynamic re-radiation pattern of trees present in the radio path were recorded at 20 and 62.4 GHz signal frequencies. The available experimental data was then used to develop a statistical model which is sought to characterize wind-induced dynamics of the point scatterers’ re-radiation function. Finally, the performance of the proposed dynamic model while predicting the received signal level fluctuations inside a tree formation scenario, was assessed against dynamic directional spectra measurements conducted in a controlled environment, for four different artificially generated wind incidences and two wind speeds, low (1.9 m/s) and high (4.7 m/s). This experiment proved that the proposed elementary model could be an asset on the characterization of the time-varying effects found in vegetation areas under wind influence.
This article presents a novel cylindrical dielectric resonator antenna (CDRA) integrated with an artificial magnetic conductor (AMC) for non-invasive monitoring of blood glucose levels (BGL) in humans. A compact, economical, and highly sensitive RF-based sensing structure for continuous glucose monitoring that resolves the drawbacks of traditional invasive techniques was developed in this work. The suggested CDRA functions within the industrial, scientific, and medical (ISM) band (2.4–2.5 GHz) and incorporates a defective ground structure (DGS) to attain resonance at 2.4 and 2.52 GHz, offering an impedance bandwidth of 300 MHz. The antenna is small, measuring 30 mm × 30 mm × 6 mm, with an initial gain of 3.6 dBi. A beehive-shaped AMC is positioned at the back of the CDRA to improve its radiation characteristics, enhancing directivity by reducing side lobe levels and increasing the gain to 7.69 dBi. The proposed CDRA is simulated using the “Hugo” bio model (38-year-old male) available in CST MWS software. It demonstrates a specific absorption rate (SAR) of 0.036 W/kg, which is within the acceptable limits of 1.6 W/kg for human exposure. The proposed CDRA was also simulated for operation with varying glucose concentrations, and a correlation between S parameter variation and glucose variation was observed. The Debye model is used to determine the dielectric characteristics of human blood for BGL values of 80 mg/dL, 110 mg/dL, 130 mg/dL, 150 mg/dL, and 170 mg/dL. The proposed CDRA was validated for radiation parameters, and the measured values matched well with the simulated ones. The proposed CDRA shows a sensitivity of 4.5 × 10 −3 dB/mg/dL. The results show that the proposed CDRA is a good candidate for measuring BGL values in humans.
The rapid evolution of wireless communication technologies necessitates innovative solutions to meet the increasing performance requirements of future networks, particularly in terms of spectral efficiency, energy efficiency, and computational efficiency. Reconfigurable Intelligent Surfaces (RIS) and Non-Orthogonal Multiple Access (NOMA) are emerging as promising technologies to enhance wireless communication systems. This paper explores the dynamic partitioning of RIS elements in NOMA systems using Deep Reinforcement Learning (DRL) to optimize resource allocation and overall system performance. We propose a novel DRL-based framework that dynamically adjusts the partitioning of RIS elements to maximize the achievable sum rate and ensure fair resource distribution among users. Our architecture leverages the flexibility of RIS to create an intelligent radio environment, while NOMA enhances spectral efficiency. The DRL model is trained online, adapting to real-time changes in the communication environment. Empirical results demonstrate that our approach closely approximates the performance of the optimal iterative algorithm (exhaustive search) while reducing computational time by up to 90 percent. Furthermore, our method eliminates the need for an offline training phase, providing a significant advantage in dynamic environments by removing the requirement for retraining with every environmental change. These findings highlight the potential of DRL-based dynamic partitioning as a viable solution for optimizing RIS-aided NOMA systems in future wireless networks.
Soundscape analysis has become integral to environmental monitoring, particularly in marine and terrestrial settings. Fish choruses within marine ecosystems provide essential descriptors for environmental characterization. This study employed a month-long sequence of continuous underwater recordings to generate 24-h spectrograms, utilizing Principal Component Analysis (PCA) specifically adapted to analyze fish choruses. The spectrograms were constructed using a frequency range from 0 to 5 kHz, represented by 1,025 spectral points (frequency bin width 5 Hz) on a linear scale. A preliminary spectral subsampling reduced the frequency components to 205 spectral points. PCA was then applied to this subsampled data, selecting 7 principal components (PCs) that explained 95% of the variance. To enhance visualization and interpretation, we introduced “acoustic maps” portrayed as heatmaps. This methodology proved valuable in characterizing the structure of the observed environment and capturing pertinent diel patterns of fish choruses. Additionally, these PCA components can be analyzed using acoustic maps to reveal hidden dynamics within the marine acoustic environment. The dimensionality reduction achieved by PCA not only streamlined data handling but also enabled the extraction of spectral information pertinent to fish choruses and the temporal dynamics of the soundscape. In conclusion, our methodology presents a versatile framework extendable to diverse biological choruses and ecoacoustic studies. The straightforward, easily interpretable analysis leverages computations derived from 24-h spectrograms, offering novel insights into the daily dynamics of biological. Choruses and contributing to future advancements in ecoacoustic research.
This paper presents an antenna-in-package (AiP) design realised with the conventional multi-layer printed circuit board manufacturing method. The design consists of a wideband 2×2 magneto-electric dipole array antenna operating from 24.25−29.5 GHz and a wideband transition from the analogue beamformer integrated into the proposed MED array antenna (IMED). The IMED array antenna has been fabricated with two distinct NXP analogue beamformer chips, i.e., MMW 9004 KC and MMW 9002 KC covering the N257 and the N258 band, respectively. The measured effective isotropic radiated power at P1dB was 35.3 dBm and 35.1 dBm for the IMED with the MMW 9004 KC and the MMW 9002 KC analogue beamformer chip, respectively. Our proposed antenna demonstrates the feasibility of designing a single wideband AiP that can be integrated with different analogue beamformers operating within the frequency band of the proposed antenna. This is true, provided the RFIC used for integration has the same footprint for RF ports, serial peripheral interface control ports, and DC power supply ports. The primary benefit of the proposed technique is the design antenna can adapt the operating frequency to different frequency standards by incorporating additional analogue chips without increasing the design complexity. This feature enables the antenna manufacturer to tailor the antenna products to different frequency standardisations depending on where the antenna will be employed. The AiP operates at 5G millimeter-wave (mmWave) frequencies, with the potential for Internet of Things applications. Furthermore, from our simulation results, the proposed IMED can potentially be extended as a phased array antenna with 2D scanning.
It is expected that 6G communication technology will achieve a peak data rate capability of 1 Tbit/s. One way of reaching this goal is to employ THz frequencies for carrying wireless signals. THz frequencies have large continuous bandwidths which allow for high data rate signals. In order to support the development of THz communications and accompanying technologies, a 6G THz Communications Testbed has been set-up at the National Physical Laboratory. In this paper, the best signal performance for a variety of different baud rates and modulation schemes is explored for both a direct connection between the waveform generator and measuring oscilloscope and for several different Over-The-Air (OTA) path lengths up to 4 m specular Non-Line-of-Sight. For the direct connection, signals of up to 210 Gbit/s were achieved and data rates of up to 150 Gbit/s were achieved for OTA transmission.
In WiFi 7 (IEEE 802.11be), Multiple Input Multiple Output (MIMO) technology plays a crucial role in enhancing throughput. This combination enables numerous applications for wearable WiFi devices. For instance, WiFi can be utilized for tracking and fall detection purposes. Additionally, wearable devices used in gaming, vital signal monitoring, and tracking can benefit from the implementation of wearable MIMO antennas. Despite the demand for wearable WiFi antennas, specifically in the new 6 GHz band, a significant gap exists in the investigation of antennas that are completely made of textile, are low profile, and provide vertical polarization and omnidirectional patterns. Addressing this gap, in this paper, a wearable planar antenna is introduced, which is specifically designed to offer an omnidirectional pattern and linear polarization. To ensure its practicality and ease of use, the antenna utilizes lightweight and wearable textile material. The design details and performance of the proposed antenna are presented. The antenna covers all three bands of WiFi, namely, 2.4 GHz, 5 GHz, and 6 GHz bands. The 10-dB return loss bandwidth is 2.4 GHz–2.5 GHz, and 4.6 GHz–7.2 GHz. The maximum Specific Absorption Rate (SAR) for an input power of 500 mW is calculated at 1.053 W/Kg for a 2 mm air gap between the antenna and tissue surface. The size of the antenna is given by a circular area of π × (50 mm) 2 , and a thickness of 6 mm.
The Internet of things is increasingly focused on UAV-based long-range applications. This necessitates versatile, low-cost antenna designs for both ground stations and drones. This study proposes the design of a pattern reconfigurable parasitic element antenna system operating in the LoRa 868 MHz band and its on-field characterization. The electronic steerable parasitic array radiator (ESPAR) antenna consists of a single-fed shorted patch surrounded by four rectangular parasitic elements. The antenna system can develop four directive beams, each activated by one of four PIN diodes, and an omnidirectional pattern obtained when all diodes are turned off. The antenna has been characterized both in an anechoic controlled environment and in a practical on-field drone-to-ground packet transmission scenario. Results based on received signal strength indicator (RSSI) show that the pattern reconfigurability becomes increasingly relevant with the end-point distance and that pointing the beam at the end point always allows the highest RSSI level to be received.
Introduction: This study is an introduction to the empirical and impact evaluation of radiofrequency electromagnetic field (RF-EMF) radiation exposure in a healthcare environment, focusing on an indoor microenvironment. It explores the expression of various genes associated with cellular responses, cell proliferation, senescence, and apoptotic cell death. The assessment analyzes current personal mobile communications (2G-5G FR1), providing a clear understanding of RF-EMF exposure and compliance with regulatory limits. Methods: The signals from different wireless communication systems at Hospital Universitario de Canarias (HUC) in Tenerife, Canary Islands, Spain, were examined in 11 locations. Four measurement campaigns were performed with frequency-selective exposimeters (PEMs) and an EME Spy 200 MVG, and experimental electric field values were compared as a long-term exposition. The frequency with the highest contribution (2.174 V/m) observed (1840 MHz) in UMTS was selected for biological effects evaluation. Results: The study focuses on four locations with the highest exposure to communication systems (downlinks), analyzing the results to verify compliance with regulations that ensure the safety of patients, the general public, and healthcare workers. LTE B20 (DL), GSM+UMTS 900 (DL), GSM 1800 (DL), UMTS 2100 (DL), and LTE B7 (DL) exhibited relatively higher E/m values throughout the campaigns, and these values consistently remained below the ICNIRP reference levels, signifying a consistently low level of exposure. In addition, this work presents the biological effects on neural stem cells (NSCs) using 3D brain organoids (BOs) exposed to RF signals in a validated and commercial experimental setting: the Gigahertz Transverse Electromagnetic cell (GTEM). The GTEM allows for the creation of homogeneous field electromagnetic fields in a small, enclosed setting and guarantees exposure conditions in a wide range of frequencies. BOs are an in vitro 3D cell-culture technology that reproduces the cellular composition and structure of the developing brain. Analyzing the expression of several genes associated with cellular responses, cell proliferation, senescence, and apoptotic cell death, we found that exposure of BOs at 1840 MHz did not affect mRNA expression in brain genes related to apoptosis or senescence. However, a decrease in gene expression for cell proliferation and cell activity markers was observed during the differentiation stage of BOs. Discussion: The discussion emphasizes the coexistence and evolution of various heterogeneous networks and services throughout the four measurement campaigns. Across all measured results, the levels of the obtained E-field were consistently well below the exposure limits set by internationally accepted standards and guidelines. These obtained values have been established in order to consider their potential effects on cell proliferation and cell activity, especially in differentiating biological organisms. Consequently, the results obtained and the methodology presented could serve as a foundational framework for establishing the basis of RF-EMF assessment in future heterogeneous 5G developments, particularly in the millimeter wave (mmWave) frequency range, where the forecast is for massive high-node density networks.
