Design and Analysis of a Ladder-Shaped Textile Antenna for SAR-Compliant Driver Fatigue Detection

Fatigue of the drivers leading to road accidents is certainly among the top causes, which warrants the creation of unobtrusive monitoring systems for road safety. In this paper, we propose a new textile-based passive RF sensor antenna that is designed and simulated in CST Studio Suite and intends to be integrated into car seats for real-time driver fatigue recognition. The antenna acts by body-coupling effects, where detuning in frequency denoted changes in driver's postures which tend to realize fatigue levels. Printed on a Dacron substrate, the antenna is flexible and durable and can thus be effectively integrated seamlessly into car seats, making it suitable for automotive and wearable applications. The ladder-shaped slot antenna operates with a peak gain of 5.063 dBi at 5 GHz, ensuring very low specific absorption rate (SAR) values that comply with FCC safety guidelines (Total SAR: 0.02757 W/kg, Max 10g SAR: 1.38851 W/kg). S11 shifts are monitored by the system, which can then process them and trigger an alert. This work demonstrates the great potential of passive RF sensing for fatigue detection and provides a non-intrusive, real-time road safety solution for drivers.