Flexible Antenna with HIS Based on PDMS Substrate for WBAN Applications

Abstract

The study of flexible dielectric material as a substrate has been increasingly considered in the recent years. The desirable substrate for wireless body area network (WBAN) application should be flexible, waterproof, stretchable, withstand against harsh environment and reliable under bad weather condition. Textile can be one of the options. However they are easily influenced by the surroundings especially when they operate in harsh environment or under bad weather conditions. Therefore, polymer such as polydimethylsiloxane (PDMS) is proposed as an alternative material which could comply with aforementioned working environment. Using PDMS as substrate, an antenna integrated with high impedance surface (HIS) is designed and studied for WBAN application at 2.4 GHz. The overall dimension of the presented design is 49.5×33×4 mm3. The design demonstrates satisfactory performance in term of gain (6.4dBi) and efficiency (~65%). Furthermore, the design has reduced radiation towards the body by 26 dB. Simulation investigations of the proposed antenna has been performed in the conditions where it is placed very close to human body and the level of the specific absorption rate (SAR) is monitored to ensure users safety. Based on the results, the proposed antenna design can be considered as an ideal candidate for WBAN devices in the future and comply with safety standards.