International audienceThe first analytical model of Body Area Network channels is presented. The formulation includes the body morphology and the characteristics of the human tissues. The studied transmission paths are along curved parts like the waist or the head. The model is derived from the diffraction theory describing the attenuation of creeping waves along a circular path on a lossy dielectric surface. The model is validated by measurements performed with Planar Inverted-F Antennas on human subjects

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Reduction of specific absorption rate (SAR) has now become a buzz word because of the growing health concerns over microwave exposure. Ferrites are found to be effective in diminishing electromagnetic influence. In this reported work, flexible polymeric ferrite sheets are characterised on the basis of their shielding efficiencies. SAR measurements are carried out with a planar wearable antenna and polymeric ferrite shielding to confirm its competence.

The goal of this paper is to study the feasibility of making intelligent antenna selection decision in IEEE 802.15.4 Wireless Sensor Networks (WSNs). This study provides us the basis to design and implement software defined intelligent antenna switching capability to wireless sensor nodes based on Received Signal Strength Indicator (RSSI) link quality metric. First, we discuss the results of our newly designed radio module (Inverted-F Antenna) for 2.4 GHz bandwidth (WSNs). Second, we propose an intelligent antenna selection strategy to exploit antenna diversity. Third, we propose the prototype of our diversity antenna for the TelosB mote and the intelligent switch design. Finally, we compare the performance of the built-in TelosB antenna with our proposed external antenna in both laboratory and realistic environments. Experimental results confirm the gain of 6 to 10 dB of the proposed radio module over the built-in radio module of the TelosB motes.

A miniaturized diversity antenna dedicated to wireless body area network (WBAN) applications is described. The combination of a planar inverted-F antenna (PIFA) and a top-loaded monopole yields distinct patterns fitting the different natures of the received waves. The strong isolation observed between the broadside and endfire ports is an important feature to limit the correlation between the received signals. The diversity gain is measured for three links and three scenarios between body-worn antennas, showing the improvement brought by the antenna diversity in the WBAN context.