oa On And Off-body Path Loss Model Using Planar Inverted F Antenna

The rapid development of biosensors and wireless communication devices brings new opportunities for Body-Centric Wireless Networks (BCWN) which has recently received increasing attention due to their promising applications in medical sensor systems and personal entertainment technologies. Body-centric wireless communications (BCWCs) is a central point in the development of fourth generation mobile communications. In body-centric wireless networks, various units/sensors are scattered on/around the human body to measure specified physiological data, as in patient monitoring for healthcare applications [1-3]. A body-worn base station will receive the medical data measured by the sensors located on/around the human body. In BCWCs, communications among on-body devices are required, as well as communications with external base stations. Antennas are the essential component for wearable devices in body-centric wireless networks and they play a vital role in optimizing the radio system performance. The human body is considered an uninviting and even hostile environment for a wireless signal. The diffraction and scattering from the body parts, in addition to the tissue losses, lead to strong attenuation and distortion of the signal [1]. In order to design power-efficient on-body and off-body communication systems, accurate understanding of the wave propagation, the radio channel characteristics and attenuation around the human body is extremely important. In the past few years, researchers have been thoroughly investigating narrow band and ultra wideband on-body radio channels. In [4], on-body radio channel characterisation was presented at ultra wideband frequencies. In body-centric wireless communications, there is a need of communications among the devices mounted on the body as well as off-body devices. In previous study, researchers have designed the antennas for on-body communications and investigated the on-body radio channel performance both in narrowband and Ultra wideband technologies. This paper presents the results of on-body and off-body path loss model using Planar Inverted F Antenna (PIFA). The antenna used in this study works at two different frequency bands as 2.45 GHz (ISM band) and 1.9 GHz (PCS band). The 2.45 GHz is used for the communication over human body surface (on-body) and 1.9 GHz is used for the communication from body mounted devices to off-body units (off-body communications). Measurement campaigns were performed in the indoor environment and anechoic chamber. A frequency-domain measurement set-up was applied. Antenna design and on and off-body path loss model results will be presented.