A reconfigurable wearable slot antenna design suitable for smart glasses

Abstract

Wearable devices are widely used in medical applications, particularly on the purpose of remote monitoring and examination of people's health. These devices form wireless links with other electronic devices to collect diverse physiological parameters of users and to transfer the collected data to an external device. Challenges encountered in keeping the quality of wireless links above the desired level, such as detuning caused by the human body and the dynamic nature of the channels, can be overcome by the utilization of recon gurable antennas in these devices. In this thesis, a pattern and polarization recon gurable wearable slot antenna design operating in the 2.4 GHz Industrial, Scienti c and Medical band is proposed. Glass is used as the substrate of the antenna making it suitable for smart glasses. The slot is an equilateral Lshaped slot that is fed by a coplanar waveguide feed. The recon guration is achieved by manipulating the slot by means of switches. Two states of switches generate two modes of operation which correspond to two L-shaped slots that are oriented in di erent directions and hence create patterns that are polarized in perpendicular to each other. Initially, the switching between the modes is achieved by using arti cial switches. Next, a PIN diode circuitry is developed as the switching mechanism. The antenna is designed analytically, optimized through numerical analysis and fabricated. The detuning e ects caused by the proximity of the human body are analysed using numerical and physical phantoms as well as human subjects. The simulation and measurement results in air, on phantoms and human subjects are compared and interpreted. Finally, a conclusion is given and possible future works are discussed.