Design and evaluation of directional antenna for shoe-mounted sensor for position identification of elderly wanderer

Abstract

Monitoring system with Bluetooth low energy (BLE) beacons is promising for position identification of elderly wanderers. BLE beacons can be mounted in shoes for convenience, and a shoe-mounted directional antenna is expected to efficiently radiate the beacon signals to the data server of the monitoring system. In this paper, a directional array antenna with planar or curved structure was designed on the shoe surface for this purpose. The antenna was designed to sweep diagonally upward from 10° to 50°, and the simulated and measured S11 performances revealed reasonable agreement. The antenna was assumed to be used in an urban environment, and a directional patch array antenna with dielectric lens was also designed to receive beacon signals by mounting it on utility poles. According to a feasibility experiment result of elderly wanderer position identification, the designed directional antenna can provide an almost 100% position identification rate if a wanderer is within 20 m from a smart phone user.

Keywords

• Position identification
• Bluetooth low energy
• Directional antenna
• Elderly wanderer
• Shoe-mounted sensor