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Off-body data communication for firefighters and other rescue workers is an important area of development. The communication with a moving person in an indoor environment can be very unreliable due to channel fading. In addition, when considering off-body communication by means of textile antennas, propagation is affected by shadowing caused by the human body. By transmitting and receiving signals using multiple-input, multiple-output antennas (MIMO communication) a large improvement in reliability of the wireless link is obtained. In this contribution, the performance of wireless data communication using quadrature phase shift keyed (QPSK) modulated data in the 2.45 GHz ISM-band is evaluated in the case of firefighters walking indoor and communicating by means of a compact dual-pattern dual-polarization diversity textile patch antenna system integrated into their clothing. Simultaneous transmit diversity (at the firefighter) and receive diversity (at the base station) up to fourth order are achieved by means of orthogonal space-time codes, providing a maximum total diversity order of 16. The measurements confirm that MIMO techniques drastically improve the reliability of the wireless link. Measurements are compared for three test persons of significantly different sizes. For equal transmitted power levels, the bit error rates for the 2\,\times\,2 and 4\,\times\,4 links are much lower than for a system without diversity, with the 4\,\times\,4 system clearly providing the best performance. [ABSTRACT FROM AUTHOR]

The need for textile-based antennas originates from the development of smart textile systems that emerged in the nineties. The aim is to increase the functionality of textiles, in most cases, clothing, by adding electronic systems. This allows the monitoring of physical (such as heart or respiration rate) as well as environmental (such as humidity or temperature) parameters through an embedded sensor network. The availability of micro electronics on the one hand, and new textile materials on the other, stimulates this evolution. The development of integratable textile-based sensors and flexible interconnections is continuously ongoing research. Also, wireless data transfer from the garment to a nearby base-station requires new developments, especially when the flexibility and comfort of the garment needs to be preserved. This paper gives a detailed overview on performed research and reveals the feasibility, design and manufacturing process of textile-based antennas for this off-body communication. The antennas are low profile, breathable, light-weight and simple in structure which make them suitable to be unobtrusively embedded in apparel and provide flexibility and satisfactory performance. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The introduction of intelligent textile systems to increase the wearer's 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 repellenee, 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. [ABSTRACT FROM AUTHOR]

So-called "wearable textile systems" are intended to improve the quality of life by enhancing the wearer's functionalities. Garments having the ability to monitor biosignals and communicate with the environment can, for example, provide continuous information about a person's state of health. These data can be valuable medical input, but also in emergency operations such as fire extinguishing, it can be a tool to decide on the operability of the fire fighter. However, wireless communication with the environment requires antennas. When preserving textile properties such as flexibility and comfort is an issue, antennas should be made fully integratable into garments and, thus, manufactured from textile material. This paper shows the feasibility of the use of textile materials in the design of antennas working in the dedicated 2.45 GHz frequency range. We used a commercial electromagnetic field simulator to design microstrip patch antennas fabricated from both conductive (electrotextiles) and nonconductive textile material. For the antenna and the ground plane, readily available electrotextiles were assessed: Flec Tron®, Shieldit™ Super and Zelt, while a fleece fabric was used for the antenna substrate. We found that such antenna prototypes had an efficiency of more than 75 %, which was comparable to conventional non textile antennas This research is an initial step in designing textile antennas and paves the way for a new generation of communicating garments. [ABSTRACT FROM AUTHOR]

The emergence of wearable antennas to be integrated into garments has revealed the need for a careful electromagnetic characterization of textile materials. Therefore, we propose in this paper a new matrix-pencil two-line method that removes perturbations in the calculated effective permittivity and loss tangent which are caused by imperfect deembedding and inhomogeneities of the textile microstrip line structure. The approach has been rigorously validated for high-frequency laminates by comparing measured and simulated data for the resonance frequency of antennas designed using the calculated parameters. The method has been successfully applied to characterize the permittivity and loss tangent of a variety of textile materials and up to a frequency of 10 GHz. Furthermore it is shown that the use of electrotextiles in antenna design influences the effective substrate permittivity. [ABSTRACT FROM PUBLISHER]