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This paper presents a flexible and wearable textile array antenna designed to generate Orbital Angular Momentum (OAM) waves with Mode +2 at 3.5 GHz (3.4 to 3.6 GHz) of the sub-6 GHz fifth-generation (5G) New Radio (NR) band. The proposed antenna is based on a uniform circular array of eight microstrip patch antennas on a felt textile substrate. In contrast to previous works involving the use of rigid substrates to generate OAM waves, this work explored the use of flexible substrates to generate OAM waves for the first time. Other than that, the proposed antenna was simulated, analyzed, fabricated, and tested to confirm the generation of OAMMode +2. With the same design, OAM Mode -2 can be generated readily simply by mirror imaging the feed network. Note that the proposed antenna operated at the desired frequency of 3.5 GHz with an overall bandwidth of 400 MHz in free space. Moreover, mode purity analysis is carried out to verify the generation of OAM Mode +2, and the purity obtained was 41.78% at free space flat condition. Furthermore, the effect of antenna bending on the purity of the generated OAM mode is also investigated. Lastly, the influence of textile properties on OAM modes is examined to assist future researchers in choosing suitable fabrics to design flexible OAM-based antennas. After a comprehensive analysis considering different factors related to wearable applications, this paper demonstrates the feasibility of generating OAMwaves using textile antennas. Furthermore, as per the obtained Specific Absorption Rate (SAR), it is found that the proposed antenna is safe to be deployed. The findings of this work have a significant implication for body-centric communications. [ABSTRACT FROM AUTHOR]

This article presents an integrated current mode configurable analog block (CAB) system for field-programmable analog array (FPAA). The proposed architecture is based on the complementary metal-oxide semiconductor (CMOS) transistor level design where MOSFET transistors operating in the saturation region are adopted. The proposed CAB architecture is designed to implement six of the widely used current mode operations in analog processing systems: addition, subtraction, integration, multiplication, division, and pass operation. The functionality of the proposed CAB is demonstrated through these six operations, where each operation is chosen based on the user’s selection in the CAB interface system. The architecture of the CAB system proposes an optimized way of designing and integrating only three functional cells with the interface circuitry to achieve the six operations. Furthermore, optimized programming and digital tuning circuitry are implemented in the architecture to control and interface with the functional cells. Moreover, these designed programming and tuning circuitries play an essential role in optimizing the performance of the proposed design. Simulation of the proposed CMOS Transistor Based CAB system is carried out using Tanner EDA Tools in 0.35 μm standard CMOS technology. The design uses a ±1.5 V power supply and results in maximum 3 dB bandwidth of 34.9 MHz and an approximate size of 0.0537 mm². This demonstrates the advantages of the design over the current state-of-the-art designs presented for comparison in this article. Consequently, the proposed design has a clear aspect of simplicity, low power consumption, and high bandwidth operation, which makes it a suitable candidate for mobile telecommunications applications [ABSTRACT FROM AUTHOR]

An internet-of-things (IoT) enabled low cost wearable device for location and information tracking system is developed to monitor and ensure the safety of the children while their parents are away either to work or abroad. This system aims to ensure human safety especially the children and efficiently initiate search and rescue in the event of emergencies. The device will notify the parents on the condition of the surroundings of the children, specifically inside the house and notify the parents if the children are outside the target area by using the application developed in the smartphone. The system uses a microcomputer called Beagle-Bone Black (BBB) as the processor while GPS and LTE technology for wireless communication. Future improvement mainly focuses on reducing the size and power consumption of the device, improving communication module, and optimizing microcomputer’s specification.

Wireless sensor network consists of nodes with limited resources. Hence, it is important to design protocols or algorithms which increases energy efficiency in order to improve the network lifetime. In this paper, techniques used in the network layer (routing) of the internet protocol stack to achieve energy efficiency are reviewed. Usually, the routing protocols are classified into four main schemes: (1) Network Structure, (2) Communication Model, (3) Topology Based, and (4) Reliable Routing. In this work, only network structure based routing protocols are reviewed due to the page constraint. Besides, this type of protocols are much popular among the researchers since they are fairly simple to implement and produce good results as presented in this paper. Also, the pros and cons of each protocols are presented. Finally, the paper concludes with possible further research directions.

An on-body location tracking system is developed and integrated with a wearable GPS antenna. Such system is beneficial in human location tracking of patients and elderly within a radius of 1 km. The system consists of a wearable antenna, a GPS module, a low cost microcontroller, two RF modules and a local monitoring system. A user equipped with the GPS antenna, GPS module and a RF transmitter is able send his/her location to the local monitoring system via a RF receiver. The proposed wearable antenna is validated to be safe for human use in terms of specific absorption rate (SAR). This antenna was then incorporated into the complete prototype and tested. Several suggestions for future improvements are also proposed and discussed.