Design of a Button Sensor Antenna for Wireless Wearable Applications

A narrow-band wearable button sensor antenna (BSA) operating between 2.4 and 2.5 GHz has been designed and it is described in this paper. The top button shape is made of a Rogers substrate, that is properly arranged on a felt substrate and a conductive e-textile ground surface and is fed via a coaxial probe on the bottom side of the ground surface. The BSA is assessed in free space and on the body's chest location. The design is simulated in various configurations and the results are promising for a wireless body area network (WBAN). In free space, the simulated bandwidth, peak gain, and radiation efficiency are 59.3 MHz, 0.755 dBi, and 90%, respectively. While on certain on-body chest locations, these values reach up to 75.6 MHz, 2.69 dBi, and 75%. Furthermore, a wide omnidirectional radiation pattern is obtained in free space and on the body's chest location, which provides robustness across diverse environments. The specific absorption rate (SAR) is relatively low. Therefore, the design is the right solution for the WBAN system.