A Q-Slot Monopole for UWB Body-Centric Wireless Communications

This paper presents a novel and simple ultrawideband printed rectangular monopole antenna 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 the calculated and measured antenna performances 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

Blockchain-IoT peer device storage optimization using an advanced time-variant multi-objective particle swarm optimization algorithm

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

Study of a printed split-ring monopole for dual-spectrum communications

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