Low-Cost Indoor Localization Using Dual-Chip RFID Tag

In this study, a low-cost dual-chip RFID tag antenna is proposed for indoor localization. The antenna integrates two RFID chips, each generating opposing radiation patterns. Angle-of-arrival based localization is performed with a single reader by analyzing the Received Signal Strength Indicator (RSSI) and the RSSI ratio of both chips. The antenna incorporates a mechanically adjustable reflector at the back that allows simple beam elevation control to tune the antenna for different indoor environments. The proposed dual-chip tag was measured in an indoor environment with different beam configurations. The localization is performed using a simple sinusoidal regression model with three model parameters and a linear regression model with two model parameters to fit the RSSI ratio of both chips and the RSSI of each individual chip, respectively. The proposed technique yields an average angle-of-arrival error better than 6.6 degrees within the tag's horizontal detection range of 4.2 meters.