Improved UHF RFID localization accuracy using circularly polarized antennas

Measurement results for multichannel transmit beamforming tag direction detection in passive ultra‐high frequency radio‐frequency identification systems

“…Preliminary measurements in a multipath environment (standard university seminar room) deliver a mean localisation accuracy of 10 cm in a 3 m × 3 m measurement grid with 25 equally spaced (0.5 m × 0.5 m) tag locations. This result slightly outperforms a similar system using receive beamforming hardware in [6].…”

“…The 3 dB beamwidths are 35° for the main axis of the antenna elements and 90° for the small axis. A self‐developed circularly polarised patch antenna is used as the AoAct unit's receive antenna (see [6]).…”

“…Tag direction measurements were conducted in a basic multipath environment (university balcony with floor reflection and one wall reflection). The AoAct unit and a self‐developed circularly polarised tag (see [6]) were positioned at a height of 1.5 m with a minimum distance of A 1 = 2.5 m (for a tag direction of 0°) to each other. The tag was moved on a straight line in front of the AoAct unit from −2.5 to 2.5 m with respect to the centre of the antenna array.…”

RFID localisation using special antenna technique

“…Although different approaches have been studied, these techniques still encounter some problems such as greater complexity of practical implementation, higher cost and lower accuracy, which have limited their practical applications. In order to improve RFID localization techniques a number of methods using new antenna design, such as phased antenna array (Huiting et al, 2015;Lee et al, 2015), leaky wave antenna (Liu et al, 2014), circularly polarized antennas (Cremer et al, 2014) and folded compact antenna (Guerchoucheet al, 2014), have been proposed. However, all these methods can only be used for indoor applications.…”