N. A. Samsuri

Effects of human body and antenna orientation on dipole textile antenna performance and SAR

Wearable textile antennas are supposed to be integrated within the clothing or secured on the body. Therefore, the placement of the antennas and their orientation need to be carefully determined. In this paper, the interaction between a single band dipole textile antenna for wireless off-body communication applications with human body is examined. The simulations are performed by means of CST Microwave Studio with a single band 2.4 GHz patch dipole antenna as the radiating source. The effects of human body are taken into account and different antenna orientations, locations and distances from the body are also considered in this study. Results have clearly indicated that the human body has notably shifts the antenna resonant frequency and modifies the radiation pattern at the frequency investigated. Furthermore, the results obtained show that the SAR values are significantly influenced by the antenna orientation and position. SAR is increased by utmost 16 % when the textile antenna is horizontally orientated compared to antenna in vertical orientation.

Compact and embroidered textile wearable antenna

Wearable electronics may provide personal systems by having our physiological status monitored which will lead to more mobility along with more efficient and effective monitoring services. This work presents the viability of investigating a fully textile wearable antenna working in the dedicated Ultra-Wideband (UWB) frequency range for indoor and outdoor applications. Such types of textile antennas can be embedded within clothing in order to enhance our capabilities without requiring any conscious thought or effort. The fabricated wearable fully textile antenna was made from both conductive and non-conductive wearable materials. Simulated and measured results in terms of return loss, bandwidth, radiation pattern, current distribution as well as gain and efficiency were presented to validate the usefulness of the proposed design.

Textile waveguide sheet with Artificial Magnetic Conductor structures for body centric wireless communication

This paper presented a textile sheet-like waveguide that incorporates Artificial Magnetic Conductor (AMC) structures. The aim is to investigate the possibility of a textile conformal waveguide in improving transmission between antennas when placed beneath them. Investigations were carried for small and belly size AMC waveguide sheets made of denim fabric. Both of the waveguide sheets exhibit promising results with S21 transmission of approximately -10dB at 5.8GHz resonant frequency. Transmission between two dipoles was enhanced with the introduction of AMC waveguide due to its inphase reflection characteristic. Promising results give future possibilities for practical realization of conformal AMC waveguide jacket made purely of textiles.

Dual band polarization insensitive metamaterial absorber in X-band

This paper presents the design of dual band polarization insensitive metamaterial absorber at 9 GHz and 10 GHz. The unit cell of the metamaterial consists of four circular rings copper with copper lines printed on 0.8 mm thick FR4 substrate with dielectric constant of 4.6 and loss tangent of 0.019. The simulated result shows that the dual band metamaterial absorber achieves 97.00% and 97.77% for normal incident electromagnetic waves at 9 GHz and 10 GHz respectively. The corresponding full width half maximum (FWHM) are 3.59% and 3.31%. The simulation result verified that the absorber well performance at any polarization of incident electromagnetic waves.

Influence of bending of 900MHz textile antenna on specific absorption rate

In this paper, the interaction between a single band textile dipole antenna with human body is examined under several bending conditions. The numerical simulations of the single band 0.9 GHz patch dipole antenna are performed by using Computer Simulation Technology (CST) Microwave Studio. The Finite Integration Technique (FIT) method is utilized to determine the antenna performance. Results have clearly indicated that the human body has more prominent effect on the antenna resonant frequency if compared to antenna bending. However, bending of the antenna has caused the radiation to penetrate deeper into the muscle tissue compared to the normal flat antenna (fat tissue).

Multiband antenna at ISM band using textille material

Two types of multiband antenna are proposed and discussed; straight dipole antenna and Koch fractal dipole antenna. Both antennas are designed to operate at three ISM band. The main aim of this paper is to design, fabricate and analysis the performance of the proposed antennas. The antennas performance was analyzed in term of reflection coefficient, efficiency, and gain. The simulations are carried out using CST Microwave Studio. The fabrication process involved conductive copper tape and denim textile as the substrate. The effect of different bending size on the antennas performance are discovered.

Investigation the performance of Koch fractal multiband textile antenna for on-body measurement

Kochs fractal multiband textile antennas are investigated for finding the best placement of antenna on the body. Two different conducting materials as the radiating element are investigated in this work; copper tape and SHIELD IT fabric. The substrate of antenna is a denim textile, which has permittivity of 1.7 and loss tangent of 0.025 at 2.5 GHz. This paper describes the investigation of antenna performance on the human body, which is the chest, the forearm, the arm and the back side of bodies. The comprehensive on-body measurements are conducted with two conditions; human with shirt and human without shirt. The experiment shows the copper tape material is better than SHIELD fabric. The suitable placement of the multiband antenna is on the backside of the body with vertical position.

Design an implantable antenna at 2.45GHz for wireless implantable body area network (WiBAN) applications

The main purpose of this paper is to design implantable printed antenna in the 2.4–2.5 GHz Industrial, Scientific and Medical service band for wireless Implantable body area network (WiBAN) Applications. Two type of printed antenna which are monopole antenna and loop antenna are designed by CST Microwave Studio Suite and the performance of both antenna are evaluated based on gain, radiation pattern, operating bandwidth and return loss. The simulation results of this paper presented guideline for designing an implantable antenna in future.

Dual-directional polarization insensitive multiband metamaterial absorber

This paper presents the design, simulation, fabrication, and measurement of dual-directional polarization insensitive multiband metamaterial absorber (MMAbs). The MMAbs is designed at three resonating frequency in X-band. The structure of MMAbs consists of two-layers 0.8 mm-thick FR4 substrate with three concentric copper rings-shaped structures at different radius printed on the top and bottom surface of the combined substrates. A full copper layer is placed between two FR4 substrates to reduce transmittance. The circular ring-shaped is very symmetry in nature consequently, the designed MMAbs insensitive to all polarization angles of incident electromagnetic (EM) waves for normal angle of incident. From simulation, three absorption peaks are obtained at 8, 10, and 12 GHz with absorbance of 97.27%, 83.55%, and 78.49% respectively for normal incident angle of EM waves. The corresponding full width half maximum (FWHM) bandwidths are 5.39% (7.77 - 8.20 GHz), 3.32% (9.78 - 10.11 GHz), and 2.57% (11.91 - 12.22 GHz). The structure is capable to operate at wide variation angle of incident wave. The operating angle which the MMAbs can absorb at least 50% of incident EM wave are 67° for both TE and TM polarizations. The simulation results are verified through experimental result. Mutual agreement is achieved between simulation and experimental results.

Leaf-shaped dual band antenna for wearable application

This paper presents the design of leaf shaped dual band flexible textile antenna. The textile antenna designed at 1.8GHz suitable for Long Term Evolution (LTE) and 2.8GHz WiMAX application. To enhance the flexibility of the proposed antenna and for the comfort of the user, denim textile is used as a substrate material. The conductive copper tape is used as the conducting element. The study also describes the energy coupled effect of two different sizes of leaf shaped to the antenna current distribution where it change the impedance and radiation characteristic of the antenna.