Tham khảo tài liệu 'development and implementation of rfid technology part 9', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | A Scientific Approach to UHF RFID Systems Characterization 231 Results and pallet readability We apply this approach to two different portal setups one is operated according to EU European and the other according to US regulations. The EU setup consists of four individual Kathrein 25-180 circularly polarized directional antennas dBic 70 H-plane 3dB-beamwidth and 30 E-plane beam width arranged in meters from ground plus a Sirit Infinity 510 UHF RFID interrogator set to 27 dBm conductive power 866 MHz and continuous wave output. The US setup consists of 4 individual Symbol Andrew RFID-900-SC high performance area antennas dBi 70 in both H and E-plane 3dB-beamwidth arranged in meters and the Sirit Infinity 510 set to 27 dBm conductive power 915 MHz and continuous wave output. TAG plane fading model results According to the proposed method the TAG-plane measurements are accomplished by means of the FSR devices. A set of 18 measurements where taken per antenna. Therefore the FSR position is varied in dimensions of a typical pallet outline and moved through the portal under test utilizing an automated transportation device see Muehlmann Witschnig 2007 . The CDFs derived from the measurement data show similar characteristics and do not depend on the antenna position see figure 12 . Hence it can be concluded that the portal interrogation zone does not depend on the portal surroundings. It can be noted that the free space field coverage is a bit higher in the US setup 50 achieved at around -10 dBm compared to -15dBm achieved in the EU setup. This is probably caused by the broader antenna beam width used in the US setup the broader beam width combined with scattering from metal object surrounding thus the portal may generate a higher level of reflections and resulting in an increasing of the field . Antenna 1 P dBm Antenna 3 P dBm Fig. 12. a CDF of the used US portal derived from the FSM measurements and fitted model .
