Current Issue : October-December Volume : 2026 Issue Number : 4 Articles : 5 Articles
This work proposes a circular-ring patch antenna using graphene as a patch material for breast tumor detection. Graphene’s high dielectric conductivity enhances the antenna’s bandwidth, making it suitable for medical applications. The antenna utilizes a Rogers substrate with overall dimensions of 30 × 30 × 0.7 mm. The ground plane is composed of copper, while the radiating patch is fabricated using graphene. The antenna is designed and simulated using CST Microwave Studio. Initially, the antenna is evaluated in free space, followed by tests on a normal breast phantom, a tumor-affected breast, and a cancerous breast using specific tissue properties to assess performance. In free space, the designed antenna exhibits an S1,1 parameter of −43.17 dB. Measurements within different breast tissue conditions show S1,1 value of −27.22 dB for normal breast tissue, −24.14 dB for a benign breast tumor, and −37.87 dB for a malignant breast tumor. Operating at 5.472, 7.416, 8.456, and 7.48 GHz, the antenna exhibits ultra-wideband (UWB) characteristics, ensuring high data transmission accuracy. The proposed antenna offers several advantages, including compact size, enhanced bandwidth, high sensitivity to tissue variations, low radiation exposure, and cost-effective implementation, making it a promising tool for early breast cancer screening, particularly in rural areas where access to advanced imaging technologies is limited....
Near-field communication is regarded as a key enabling technology for future 6G wireless systems. However, when operating over wide bandwidths, the beam split effect arising from frequency-independent analog phase shifters leads to significant beamforming gain degradation. Different from existing works that address this issue through true-time-delay hardware, this paper exploits the emerging movable antenna technology for beam split alleviation. Specifically, we consider a movable antenna-enabled near-field wideband uplink system with an analog beamforming architecture. Under this setup, we jointly optimize the analog phase shifts and antenna positions to maximize the minimum beamforming gain across all subcarriers. The formulated problem is highly non-convex due to the constantmodulus constraint on the analog combiner and the nonlinear dependence of the near-field channel on antenna positions, which makes conventional optimization methods difficult to apply. To this end, we develop a deep reinforcement learning framework based on the soft actor–critic algorithm that operates in a continuous action space and effectively handles the non-smooth max-min objective. Simulation results show that the proposed approach alleviates the beam split effect and achieves a higher minimum beamforming gain than conventional schemes....
Courses in electromagnetism and related technical subjects are often dominated by lecture-heavy instruction and complex mathematical concepts, which can make it difficult for students to stay engaged. This is particularly problematic in today’s hyper-digitalized society, where constant screen exposure and shortened attention spans challenge traditional learning methods. While computer-based tools and hands-on laboratories offer some pedagogical improvements, they often fall short in terms of interactivity, dynamism, adaptiveness, and student engagement. In an effort to enrich the learning experience and boost student motivation, we have created a gamified learning activity for the undergraduate course “Radiocommunications”—commonly referred to as Antennas and Propagation in other institutions— implemented in the form of a question-based board game. The activity, carried out over three academic years, is fully aligned with the course syllabus and encourages active learning, healthy competition, and collaborative problemsolving. Custom-made materials—including a game board, 270 question cards, wildcards, and incentive-based rewards—were developed specifically for this purpose. The qualitative results from a student survey, together with statistical evidence from hypothesis testing, suggest that the activity enhances conceptual understanding, helps students connect ideas across related subjects, and contributes to a more motivating and enjoyable learning experience....
Low Earth Orbit (LEO) satellite constellations offer unprecedented opportunities for global broadband connectivity but pose significant beamforming challenges due to rapid platform motion and stringent onboard hardware constraints. Fully digital architectures, while optimal in theory, remain impractical for satellite payloads, motivating hybrid analog- digital designs that combine a reduced set of RF chains with analog phase shifter networks. In this work, we first quantify the required update rate for analog beam steering weights as a function of orbital altitude and array aperture size. We show that it is sufficient to update the analog beam steering vectors on the scale of seconds, even for larger arrays at lower altitudes. We then introduce a thresholdbased algorithm that adaptively triggers analog beam steering updates, further reducing the frequency of steering events for a negligible sum- rate degradation. Finally, we propose an adaptive digital precoding (ADP) scheme that recomputes regularized zero- forcing (RZF)- based digital precoder only when interference leakage exceeds a tunable threshold, halving onboard matrix inversions for around a 6% average system sum- rate penalty. Monte Carlo simulations validate that these techniques jointly achieve near- optimal sum- rate performance while dramatically lowering both hardware and computational burdens, paving the way for practical, energy- efficient beamforming in next- generation LEO constellations....
Wearable antenna arrays play a critical role in enabling reliable wireless connectivity for Internet of Things (IoT) applications in smart-city environments. However, achieving stable electromagnetic performance, low specific absorption rate (SAR), and mechanical robustness using low-cost textile materials remains a challenge. In this work, a single-layer 1 × 2 rectangular microstrip patch antenna array operating at 2.45 GHz is designed, fabricated, and experimentally evaluated using three textile substrates (felt, denim, and polyester) and two conductive materials (copper tape and conductive fabric). The antennas are characterized in terms of impedance matching, gain, radiation pattern, bending-induced detuning, and SAR compliance. The results demonstrate that material selection has a dominant influence on antenna performance, with the denim–conductive fabric configuration providing the most balanced trade-off between gain (2.04 dBi), impedance stability, and mechanical flexibility. SAR analysis shows values of 0.005 W/kg (1 g) and 0.015 W/kg (10 g) at 2.45 GHz, which are significantly below international safety limits and achieved without the use of artificial magnetic conductors or electromagnetic bandgap structures. Bending analysis reveals a predictable frequencyshift behavior, enabling design-level compensation for wearable operation. The proposed antenna array offers a low-profile, costeffective, and safe solution for smart-city-wearable IoT applications....
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