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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.

The purpose of this paper is to numerically determine the distribution of electric fields registered by a personal exposimeter (PEM) used for the Global System for Mobile Communications (GSM) around 900 MHz (GSM900) downlink (DL) band and compare these with calibration measurements of PEMs worn by real human subjects.

Numerical simulations using the Virtual Family Male (VFM) are carried out at 950 MHz in order to determine the electric fields surrounding the phantom in realistic, far-field environments. These electric fields can be used to determine the distribution of a PEM’s response when worn by the VFM. Simultaneously, calibration measurements in an anechoic chamber are carried out using a real PEM worn by two different subjects, in order to determine the PEM’s response experimentally.

Both the numerical simulations and the measurements show that a PEM will on average underestimate the incident electric fields in the GSM900 DL band and that the variation (expressed in terms of the 95 percent confidence interval and the interquartile distance) on its response is relatively large: a 95 percent confidence interval of 22 dB and an interquartile distance of 7.3 dB are found in a realistic environment using numerical simulations, while the calibration measurements show interquartile distances up to 12 dB. In terms of variation there is an excellent agreement between simulations and measurements.

This paper proves that numerical simulations may be used as a replacement for the more time- and work-consuming calibration measurements if the variation of a PEM’s response is studied.