A shared aperture 2-element multiple-input-multiple-output (MIMO) antenna design for 5G standards is presented in this study, one which uses the same radiating structure to cover both the sub-6GHz and millimeter-wave (millimeter-wave) bands. The proposed antenna comprises four concentric pentagonal slots that are uniformly separated from one another. For the sub-6GHz band, the antenna is excited by a single open-end microstrip transmission-line, while a 1 × 8 power divider (PD) connected via a T-junction structure excites the millimeter-wave band. Both the sub-6GHz and mm-wave antennas operate in a MIMO configuration. The proposed antenna design was fabricated on a 120 × 60 mm² substrate with an edge-to-edge distance of 49 mm. The proposed sub-6GHz antenna covers the following frequency bands: 4–4.5 GHz, 3.1–3.8 GHz, 2.48–2.9 GHz, 1.82–2.14 GHz, and 1.4–1.58 GHz, while the millimeter-wave antenna operates at 28 GHz with at least 500 MHz of bandwidth. A complete antenna analysis is provided via a step-by-step design procedure, an equivalent circuit diagram showing the operation of the shared aperture antenna, and current density analysis at both millimeter-wave and sub-6GHz bands. The proposed antenna design is also characterized in terms of MIMO performance metrics with a good MIMO operation with maximum envelop correlation coefficient value of 0.113. The maximum measured gain and efficiency values obtained were 91% and 8.5 dBi over the entire band of operation. The antenna is backward compatible with 4G bands and also encompasses the sub-6GHz and 28 GHz bands for future 5G wireless communcation systems.

The requirement of mounting several access points and base stations is increasing tremendously due to recent advancements and the need for high-data-rate communication services of 5G and 6G wireless communication systems. In the near future, the enormous number of these access points might cause a mess. In such cases, an optically transparent antenna (OTA) is the best option for making the environment more appealing and pleasant. OTAs provide the possible solution as these maintain the device aesthetics to achieve transparency as well as fulfill the basic coverage and bandwidth requirements. Various attempts have been made to design OTAs to provide coverage for wireless communication, particularly for the dead zones. These antennas can be installed on building windows, car windscreens, towers, trees, and smart windows, which enables network access for vehicles and people passing by those locations. Several transparent materials and techniques are used for transparent antenna design. Thin-film and mesh-grid techniques are very popular to transform metallic parts of the antenna into a transparent material. In this article, a comprehensive review of both the techniques used for the design of OTAs is presented. The performance comparison of OTAs on the basis of bandwidth, gain, transparency, transmittance, and efficiency is also presented. An OTA is the best choice in these situations to improve the aesthetics and comfort of the surroundings with high antenna performance.

Several research articles are available in the literature regarding the design of antennas, but hardly (to the best of authors’ knowledge) few papers covered the antennas that are designed for the detection, diagnostics, and monitoring of various diseases. There is a need for a research article in which the design and performance of such significant antennas should be compared and highlighted based on various available design techniques to enhance performance parameters that include efficiency, bandwidth, size and appropriate bio-compatible material used to transmit data from the human body efficiently. Antennas are essential in biomedical applications for wireless communication, miniaturization, integration, implantable devices, diagnostic imaging, biotelemetry, and biosensing. They enable efficient and reliable wireless connectivity, facilitating remote monitoring, improving patient care, and advancing medical research. Designing biomedical antennas presents several challenges, including miniaturization and integration into compact devices, ensuring biocompatibility with the human body, conforming to biological structures, mitigating electromagnetic interference (EMI), accounting for signal attenuation and propagation in the body, optimizing power efficiency, and ensuring compliance with regulatory standards. Overcoming these challenges requires expertise in antenna design, biocompatibility, electromagnetic modelling, and collaboration between disciplines. Therefore, a detailed review is required so that any scholar who wishes to excel in this field may read this review to understand future directions better and work already done for the design of biomedical antennas. This review comprises a comparison of several significant biomedical antenna design techniques used for the detection, diagnosis and monitoring of various diseases, which can be helpful for the medical community for the detection of various diseases, including skin cancer, breast cancer, lungs cancer, endoscopy, brain tumor and glucose level detection. The various features of biomedical antennas are thoroughly investigated to provide performance metrics of the antennas designed to diagnose various diseases. The advantage of this study is the understanding of different types of antennas for various diseases. This study also allows realizing appropriate bio-compatible materials and flexible materials for biomedical antenna design, the effect of Specific Absorption Rate (SAR) on human/animal body and finally, the tables provide the antenna performance in terms of gain, bandwidth, and directivity with respect to antenna size and type of substrate material used for each disease. These biomedical antennas have several applications for diagnosis, early-stage cancer detection and, in some cases providing enough energy to cure the cancer cells in the human/animal body. Moreover, the implementation of Machine learning algorithms for the early detection of tumor for the above-mentioned diseases is also discussed.

In the present work, an attempt is made to enhance the productivity of a double slope solar still by using an immersion type water heater. The effect of using an external fan to cool the glass surface is also examined. Experiments were carried out for winter season in Saudi Arabian climatic conditions at latitude 26 deg N. A solar still with 35 deg glass slope angle is chosen in our study. Since the yield of a solar still is more for low water depths, the water level in the base tank was maintained at 1 cm. The experimental results showed that the productivity increased by a significant 370% when two water heaters each having 500 W capacities was used. When external cooling fan was used the productivity was found to decrease by 4% and 8% for wind speeds of 7 m/s and 9 m/s, respectively. Thermal modeling was also done using the heat and mass transfer relations, and then, numerical simulations were carried out to validate with the experimental results. A good agreement between experimental and numerical results was found. The present study is partial implementation of two patents submitted in this field.

This work presents a compact meandered loop slot-line 5G antenna for Internet of Things (IoT) applications. Recently, sub-gigahertz (sub-GHz) IoT technology is widely spreading. It enables long-range communications with low power consumption. The proposed antenna structure is optimized to operate at sub-GHz bands without any additional complex biasing circuitry or antenna structure. A miniaturized design was achieved by a meandered structured loop slot-line that is loaded reactively with a varactor diode. Wideband frequency reconfigurability (FR) was achieved by the use of the varactor diode. The proposed antenna resonates over the frequency band of 758–1034 MHz with a minimum bandwidth of 17 MHz over the entire frequency band. The RO4350 substrate with dimensions of 0.18λ_g × 0.13λ_g mm² is used to design the proposed antenna design. The efficiency and gain values varied from 54–67% and 0.86–1.8 dBi. Compact planar structure, narrow-band operation (suitable for NB-IoT) and simple biasing circuitry, which allows for sub-GHz operation, are unique and attractive features of the design.

In this study, an experimental and numerical investigation was carried out to obtain lift, drag, and pitching moment data on 65 degree delta and 65/40 degree double-delta wings. The experimental tests were conducted at the King Fahd University of Petroleum and Minerals low-speed wind-tunnel facility, whereas the numerical tests were performed using the commercial computational fluid dynamics software FLUENT. Results from both experiments and numerical predictions were compared to other experimental data found in literature as well as to the theory of Polhamus. The results of comparison of surface pressure coefficient distribution and vortex breakdown location show good agreement with experiments. Overall, the comparison of result shows good agreement between different experimental studies as well as good agreement with the computational fluid dynamics predictions and the theoretical calculations.