Wearable antenna pressure sensor with electromagnetic bandgap for elderly fall monitoring

Abstract

In this paper, a wearable antenna pressure sensor with electromagnetic bandgap (EBG) is proposed, which can be used to monitor the walking and fall states of the elderly. When the elderly walks and falls suddenly, the knee or elbow wearing the antenna sensor will touch the ground and put a lot of pressure on the antenna sensor, resulting in the resonance frequency shifts. The proposed antenna sensor is fabricated on flexible silicone substrate and works in the 2.45 GHz industrial, scientific and medical (ISM) band. A 3 × 3 EBG array is designed to reduce the specific absorption rate (SAR) of the antenna to the human body and increase the forward peak gain of the antenna from 1.63dBi to 4.36dBi. Furthermore, the antenna sensor exhibits high sensitivity of about 11 MHz/N to the pressure. To verify the simulated results, the sensing properties of the wearable antenna sensor were measured. The measured results have been found to be consistent with the simulated ones. Moreover, the bending performance study and SAR analysis reveal that the proposed antenna sensor is a good candidate for wearable devices.