Textile Diamond Dipole and Artificial Magnetic Conductor Performance under Bending, Wetness and Specific Absorption Rate Measurements

Textile diamond dipole and Artificial Magnetic Conductor (AMC) have been proposed and tested under wearable and body centric measurements. The proposed antenna and AMC sheet are entirely made of textiles for both the substrate and conducting parts, thus making it suitable for wearable communications. Directive radiation patterns with high gain are obtained with the proposed AMC sheet, hence minimizing the radiation towards the human body. In this study, wearable and body centric measurements are investigated which include bending, wetness and Specific Absorption Rate (SAR). Bending is found not to give significant effect to the antenna and AMC performance, as opposed to wetness that yields severe performance distortion. However, the original performance is retrieved once the antenna and AMC dried. Moreover, notable SAR reduction is achieved with the introduction of the AMC sheet, which is appropriate to reduce the radiation that penetrates into human flesh

Wide to multiband elliptical monopole reconfigurable antenna for multimode systems applications

Wideband-multiband reconfigurable elliptical monopole antenna is investigated in this paper. By having conventional elliptical monopole antenna, wideband operating frequency is obtained. With the combination of dual pairs of slotted arms and a band-pass filter on the ground plane of the elliptical monopole, multiband is achieved. Dual-band operating frequencies at 1.6 GHz and 2.6 GHz while wideband operates from 3.35 GHz to 9 GHz. Therefore, wide range of wireless communication systems is obtained from the proposed antenna to support the multiband mode (i.e. GPS and LTE) and UWB systems. Frequency reconfigurable is achieved by controlling the switches integrated on the antenna structure. Simulated results of reflection coefficient, radiation patterns and gain performance are presented. The proposed antenna design is suitable candidate for different wireless communication applications

A novel composite web service selection based on quality of service

Using the internet, as a dynamic environment thanks to its distributed characteristic, for web service deployment has become a crucial issue in QoS-driven service composition. An accurate adaption should be undertaken to provide a reliable service composition which enables the composited services are being executed appropriately. That is, the critical aspect of service composition is the proper execution of combination of web services while the appropriate service adaption performed with respect to predetermined functional and non-functional characteristics. In this paper, we attempts to deliberate the optimization approaches to devise the appropriate scheme for QoS-based composite web service selection

Meander bowtie Antenna for Wearable Application

This paper proposes a flexible compact bowtie antenna for medical application that operates at 2.45 GHz. The proposed antennas are miniaturized using meander technique. Both substrates and conducting material of the antenna are made of flexible material semi-transparent film as the substrate and shieldit fabric as the conducting material which suitable for wearable and on body application. The results show that the total length of the antenna is significantly reduced by up to 38%. However, the gain of the antenna is slightly decreased when the size of the antenna become smaller. The results of this research could provide guidance and has significant implication for future development of wearable electronics especially in medical monitoring application

External attacks on automotive system through wireless communication channels

The reliance of today’s automotive system on electronics control system is expected to make the cars to be state-of-the-art vehicle. However, this technology dependency results in the cars to be exposed to attacks by the hacker through the manipulation of electronics system. Previously, for the attacker to compromise car’s system, he/she must access the car directly and internally. However, with the incorporation of wireless technologies such as Bluetooth and cellular into automotive system for example in its telematic units, the attacks are evolved from internal attacks into remote attack where the adversary does not have to internally access the car’s system. This paper analyses the vulnerabilities of the automotive system by the remote attacks performed through Bluetooth and cellular. Once the vulnerabilities were analyzed, the threats imposed by these vulnerabilities are accessed. Two scenarios namely theft and surveillance are used to exemplify the threats that are carried by the vulnerability of the automotive system to the remote attacks. From the vulnerability analysis and threat assessment, it can be deduced that the automotive system is vulnerable to attacks and proper countermeasure must be taken to curb the implication from the attacks.Keywords: Hardware Trojan, Insertion, Third-part IP, Trus

Textile diamond dipoles for body centric communications at 2.45GHZ and 5.8GHZ

This study proposes textile diamond dipoles for body centric communication that operate at 2.45GHz and 5.8GHz. The proposed antennas have been rigorously tested under wearable and body centric measurements. Both substrates and conducting parts of the diamond dipoles are entirely made of textiles; which is deemed fit for wearable communications. Experiments such as bending, wetness and SAR were performed to investigate the antennas' performance for body communication realization. Bending was found not to cause any significant performance disruption. On the other hand, since the proposed antenna is not made of water-proof material, the performance was distorted under wet condition. However, once the antenna was dried out, the original performance was achieved. SAR measurement was also conducted and significant SAR values were observed when placing the proposed diamond dipoles close to human body

Design and analysis of flexible bow-tie antenna for medical application

This research presents an extensive investigation and analysis of bow-tie antenna performance made of three different flexible materials as the substrates. The antenna performance is address in terms of S11 and radiation pattern. The flexible antenna performance is simulated in free space condition and compared to the antenna performance in on-body environment. The aim of this research is to choose suitable flexible dielectric substrate which sustains its performance under on-body environment. The results of this research could provide guidance and has significant implication for future development of wearable electronics especially in medical monitoring application

A parametric study of textile artificial magnetic conductor with wire dipole at 2.45GHZ and 5.8GHZ

Textile Artificial Magnetic Conductor (AMC) with wire dipole is presented. The AMCs are made of fleece and Shieldit fabrics and were designed to have in-phase reflections at 2.45GHz and 5.8GHz. Thorough parametric studies based on AMC unit cell have been performed to obtain the optimized design. Performance comparison between different types of environments, fabrics and arrays size were also conducted. The proposed AMC and wire dipole are designed, simulated, fabricated and tested. Results of return loss, radiation pattern and gain are presented. Results show that forward directive radiation pattern with improved gain are achieved with the introduction of the AMC at both 2.45GHz and 5.8GHz. The proposed textile AMC is suitable for body centric communication systems

Modelling the effect of applied voltage and frequency on electroluminescence in polymeric material

Electroluminescence method has been used by several researchers to observe the behaviour of an aged polymeric material. Electroluminescence is a phenomenon that occurs when the atoms of a material are being excited due to the application of and external high electrical stresses. The changes in the energy level of these excitation states can be used as an indicator for the initiation of electrical ageing. There are several factors that affect the behaviour of electroluminescence emission such as, among others, applied voltage, applied frequency, ageing of material and types of materials and gases used are discussed in this paper. A mathematical approach relating these factors and the intensity of electroluminescence is proposed through the aid of Dimensional Analysis method. A close relationship is obtained between experimental and simulation that suggests this mathematical approach can be utilized as a tool to predict electrical ageing of insulation material

Quarter wavelength fabry–perot cavity antenna with wideband low monostatic radar cross section and off-broadside peak radiation

Since antennas are strong radar targets, their radar cross section (RCS) reduction and radiation enhancement is of utmost necessity, particularly for stealth platforms. This work proposes the design of a Fabry–Perot Cavity (FPC) antenna which has wideband low monostatic RCS. While in the transmission mode, not only is gain enhancement achieved, but radiation beam is also deflected in the elevation plane. Moreover, the design is low-profile, i.e., the cavity height is ~λ/4. A patch antenna designed at 6 GHz serves as the excitation source of the cavity constructed between the metallic ground plane and superstrate. The superstrate structure is formed with absorptive frequency selective surface (AFSS) in conjunction with dual-sided partially reflective surface (PRS). Resistor loaded metallic rings serve as the AFSS, while PRS is constructed from inductive gradated mesh structure on one side to realize phase gradient for beam deflection; the other side has fixed capacitive elements. Results show that wideband RCS reduction was achieved from 4–16 GHz, with average RCS reduction of about 8.5 dB over the reference patch antenna. Off-broadside peak radiation at −38◦ was achieved, with gain approaching ~9.4 dB. Simulation and measurement results are presented