A conformal leaky-wave antenna design for IoMT-based WBANs

Continuous health monitoring of vital signs of patients is a challenging issue, especially in emergency medical conditions. This paper designs a practical internet of medical things-based wireless body area network (IoMT-based WBAN), to address this issue. Accordingly, a two-fold test-bed design is proposed taking i) signaling and ii) antenna configuration into account to attain uninterruptible on/off-body communication links. Firstly, the Walsh-Hadamard coding technique is used in all bio-sensors to retain orthogonal simultaneous signaling for on-body links. Secondly, an antenna configuration of the hub is designed so that it prevents probable interruptions in off-body links which may be caused by some human postures. More accurately, a novel periodic leaky-wave antenna (LWA) with an elliptical belt shape is introduced which generates a quasi-omnidirectional pattern. The LWA is designed based on a multi-tone periodicity of a width-modulated microstrip line. At the design frequency of 5.8 GHz, the suggested conformal periodic LWA was simulated and then fabricated. Simulations and measurement results illustrate that the performance of on/off-body communication links is improved in comparison to conventional antennas. Furthermore, simulated and measured radiation patterns have a good agreement with theoretical calculations. Moreover, specific absorption rate (SAR) values of the proposed antenna are significantly below the SAR limits so that this technique can be highly recommended for WBAN applications.