Radiation-Pattern-Reconfigurable Antenna Using Monopole-Loop for Fitbit Flex Wristband

This letter presents a radiation-pattern-reconfigurable antenna for a Fitbit Flex wristband, which provides health information about the human body. The advantages of this antenna are improvements in antenna performance and controlling beam directions compared to the existing antenna for the Fitbit Flex. We proposed the placement of an antenna on the upper side of the Fitbit Flex wristband as a monopole antenna. We compared the existing Fitbit Flex antenna to the proposed antennas by several antenna performance factors. Total radiation power (TRP) and total isotropic sensitivity (TIS) are measured, and the specific absorption rate (SAR) result is simulated. The proposed antennas show improvement in performance when compared to the existing Fitbit Flex existing antenna.