Hendrik Rogier

A Textile Antenna for Off-Body Communication Integrated Into Protective Clothing for Firefighters

The introduction of intelligent textile systems to increase the wearers level of protection has exposed the necessity of wearable communication tools and has led to research in textile antennas. However, most textile fabrics are quite thin (0.5 mm), making it challenging for antenna designers to provide an antenna which operates adequately and resiliently in the 2.4-2.4835-GHz industrial-scientific-medical bandwidth. Flexible pad foam is commonly available in protective clothing and overcomes these constraints by providing a uniform, stable, and sufficient thickness. Moreover, its cellular structure and properties, such as flame retardance and water repellence, make it an excellent substrate material for the integration of antennas into protective garments. In this paper, we describe the design, manufacture, and performance of the first textile planar antenna to be implemented on flexible protective foam, suitable for firefighter garments. We employed shock absorbing foam with a thickness of 3.94 mm and achieved a nearly circularly polarized antenna with a bandwidth of more than 180 MHz even when the antenna was compressed or bent. These outstanding substrate and antenna characteristics result in an antenna that is highly appropriate for garment integration.

Aperture-Coupled Patch Antenna for Integration Into Wearable Textile Systems

The emergence of wearable textile systems in recent years exhibited the need for wireless communication tools integratable into garments. In literature, several planar antenna designs based on textile materials have been presented, however, without an adapted feeding structure for wearable applications. An aperture-coupled patch antenna (ACPA) meets this requirement since the rigid coaxial feed is replaced by a microstrip feed line that couples its power into the antenna through an aperture in the ground plane. This letter presents the first ACPA entirely made out of textile material. The result is a highly efficient, fully flexible, and wearable antenna that is integratable into garments.

Design of an Implantable Slot Dipole Conformal Flexible Antenna for Biomedical Applications

We present a flexible folded slot dipole implantable antenna operating in the Industrial, Scientific, and Medical (ISM) band (2.4-2.4835 GHz) for biomedical applications. To make the designed antenna suitable for implantation, it is embedded in biocompatible Polydimethylsiloxane (PDMS). The antenna was tested by immersing it in a phantom liquid, imitating the electrical properties of the human muscle tissue. A study of the sensitivity of the antenna performance as a function of the dielectric parameters of the environment in which it is immersed was performed. Simulations and measurements in planar and bent state demonstrate that the antenna covers the complete ISM band. In addition, Specific Absorption Rate (SAR) measurements indicate that the antenna meets the required safety regulations.

Influence of Relative Humidity on Textile Antenna Performance

The next generation of garments is sensorized, and therefore requires an adapted wireless communication tool such as a textile antenna. However, when integrating this flexible antenna into clothing, stable and reliable functioning in the operating frequency range is required. Climatic changes, especially altering relative humidity, might influence the textile antenna performance. This effect has to be taken into consideration when selecting the textile materials that comprise the antenna. A variety of antenna substrate materials has been investigated in this paper. It was found that antennas based on materials with a small moisture regain (less than 3 %) provided a more stable antenna characteristic, and can therefore preferably be applied as antenna substrate.

A Hybrid UCA-RARE/Root-MUSIC Approach for 2-D Direction of Arrival Estimation in Uniform Circular Arrays in the Presence of Mutual Coupling

A new hybrid algorithm that combines the uniform circular array-RAnk REduction (UCA-RARE) and Root-MUSIC algorithm for 2-D direction-of-arrival (DOA) estimation of azimuth and elevation angle is presented for uniform circular arrays in the presence of mutual coupling. To describe mutual coupling and platform effects we rely on the circular symmetry and expand the open-circuit voltages into a limited number of phase modes. This number of phase modes only depends on the electromagnetic dimensions of the UCA and is independent of the severity of mutual coupling in the UCA. The UCA-RARE algorithm is then applied to estimate the azimuth angle independent from the elevation angle. Next, for each azimuth angle we perform a new search-free rooting algorithm based on the expansion of the array manifold into a double Fourier series. By considering several examples, it is shown that even in the presence of severe mutual coupling the proposed combined technique yields very robust DOA estimations for azimuth angle as well as for elevation angle

Compact Half Diamond Dual-Band Textile HMSIW On-Body Antenna

A novel wearable dual-band textile antenna, designed for optimal on-body performance in the 2.4 and 5.8 GHz Industrial, Scientific and Medical bands, is proposed. By using brass eye-lets and a combination of conducting and non-conductive textile materials, a half-mode substrate integrated waveguide cavity with ground plane is realized that is very compact and flexible, while still directing radiation away from the wearer. Additional miniaturization is achieved by adding a row of shorting vias and slots. Beside excellent free space performance in the 2.4 and 5.8 GHz bands, respectively, with measured impedance bandwidth of 4.9% and 5.1%, maximal measured free-space gain of 4.1 and 5.8 dBi, and efficiency of 72.8% and 85.6%, very stable on-body performance is obtained, with minimal frequency detuning when deploying the antenna on the human body and when bent around cylinders with radii of 75 and 40 mm. At 2.45 and 5.8 GHz, respectively, the measured on-body gain is 4.4 and 5.7 dBi, with sufficiently small calculated SAR values of 0.55 and 0.90 W/kg. These properties make the proposed antenna excellently suited for wearable on-body systems.

Wireless Communication for Firefighters Using Dual-Polarized Textile Antennas Integrated in Their Garment

A compact wearable antenna system, completely made out of textile materials for integration into protective garments, is proposed. The system implements combined pattern and polarization diversity to improve the quality of the communication link. The performance of the on-body antenna system, integrated into a firefighter jacket worn by a test person, was investigated in an indoor measurement campaign. Several receiver diversity schemes and different combining techniques were evaluated in terms of bit error rate, signal-to-noise ratio and signal correlations. By comparing them to theoretical results, we demonstrate the reliability of the proposed system and the advantage of using diversity.

Two-dimensional optical phased array antenna on silicon-on-insulator.

Optical wireless links can offer a very large bandwidth and can act as a complementary technology to radiofrequency links. Optical components nowadays are however rather bulky. Therefore, we have investigated the potential of silicon photonics to fabricated integrated components for wireless optical communication. This paper presents a two-dimensional phased array antenna consisting of grating couplers that couple light off-chip. Wavelength steering of

Wireless Power Transmission: R&D Activities Within Europe

0.24 degrees /nm is presented reducing the need of active phase modulators. The needed steering range is

Permittivity and Loss Tangent Characterization for Garment Antennas Based on a New Matrix-Pencil Two-Line Method

1.5 degrees . The 3dB angular coverage range of these antennas is about