New measurement results for the localization of UHF RFID transponders using an Angle of Arrival (AoA) approach

In this paper we present new measurement results for an Angle of Arrival (AoA) approach to localize RFID tags at 868 MHz. Self-designed three element antenna arrays, off-the-shelf IDS R901G RFID reader ICs, and UPM Raflatec DogBone RFID tags are used to generate and detect ISO 18000-6C compliant signals. The experimental setup comprises three antenna arrays and a test environment of size 3 times 3 square meters with 25 test points. The AoA is estimated using the phase differences in the complex baseband signals of adjacent antenna elements within one array. A mean positioning error of 0.21 m was achieved for the considered test grid.