Abstract-This paper presents a novel and simple ultrawideband (UWB) printed rectangular monopole antenna (PRMA) for body-centric wireless communications. The design is based on etching a Q-slot on a rectangular radiator, and is optimized to produce the largest bandwidth in free space and close to the human body. We analyze the design of the proposed antenna and assess its performance in terms of bandwidth, gain, efficiency, and radiation patterns. We also characterize the antenna in the time-domain by calculating its fidelity factor. Our results show that the Q-slot antenna maintains its bandwidth when placed in close contact with the human body, or in contact with breast-mimicking tissue phantoms. The very good agreement between calculated and measured antenna performance in free space and on body suggests that the antenna is immune to variations in the human tissue, and is also robust to fabrication tolerances.
The integration of Internet of Things devices onto the Blockchain implies an increase in the transactions that occur on the Blockchain, thus increasing the storage requirements. A solution approach is to leverage cloud resources for storing blocks within the chain. The paper, therefore, proposes two solutions to this problem. The first being an improved hybrid architecture design which uses containerization to create a side chain on a fog node for the devices connected to it and an Advanced Time-variant Multi-objective Particle Swarm Optimization Algorithm (AT-MOPSO) for determining the optimal number of blocks that should be transferred to the cloud for storage. This algorithm uses time-variant weights for the velocity of the particle swarm optimization and the non-dominated sorting and mutation schemes from NSGA-III. The proposed algorithm was compared with results from the original MOPSO algorithm, the Strength Pareto Evolutionary Algorithm (SPEA-II), and the Pareto Envelope-based Selection Algorithm with region-based selection (PESA-II), and NSGA-III. The proposed AT-MOPSO showed better results than the aforementioned MOPSO algorithms in cloud storage cost and query probability optimization. Importantly, AT-MOPSO achieved 52% energy efficiency compared to NSGA-III. To show how this algorithm can be applied to a real-world Blockchain system, the BISS industrial Blockchain architecture was adapted and modified to show how the AT-MOPSO can be used with existing Blockchain systems and the benefits it provides.
In this study, we present a low-profile dual-spectrum split-ring monopole that operates at industrial, scientific and medical (ISM) (2.45 GHz) band and ultrawideband (UWB) spectrum (3.1–10.6 GHz). We optimised the design for dual-band operations by using circular split-ring radiators. The coupling between both rings drives the structure to achieve quasi-resonance frequencies in the UWB spectrum. A small stub combines the two radiators and both behave as a single element that enables the antenna to resonate at ISM band 2.45 GHz. The antenna achieves the desired characteristics in terms of good impedance matching, radiation properties as well as other physical and practical requirements such as compact geometry, planar profile and easy fabrication. The very good agreement between the simulated and measured results show that the proposed antenna has the potential for dual-band application.
In this paper, indoor propagation characteristics for TV white space (TVWS) frequency bands are studied. Measurements in the actual indoor environment are performed and described. An indoor propagation model for TVWS is developed, which is useful for evaluating secondary-secondary interference in TVWS scenarios, and its empirical parameters are derived according to measurement results. Our proposed model is based on components of free space path loss, penetration losses of walls and floors, an attenuation coefficient against distance, and an attenuation constant. Frequency dependency of these parameters is derived. Our proposed model is compared with representative indoor models from the literature. Results show that our proposed model, with the obtained empirical parameters, achieves better performance than representative indoor models. The standard deviation of estimation error for our proposed model is only 5.9 dB.
Balanced Antipodal Vivaldi Antennas (BAVAs) have been recently proposed for ultra-wideband (UWB) microwave imaging in medical applications such as breast cancer detection. This paper presents a modified design that allows the use of wideband BAVAs in microwave tomography, where the frequency range of interest is significantly lower than the UWB range down to 1 GHz. The performance of the antenna is evaluated using full-wave electromagnetic simulations.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.