Effects of Reader Antenna Orientation on Received Signal Strength of UHF RFID Tags for Handheld Reader Localization

摘要

Experimental studies on localization of a handheld UHF RFID reader in an environment with reference RFID tags are presented in this paper. The handheld reader provides an omnidirectional radiation pattern with two nulls. Depending on the orientation of the reader and its antenna, the received signal strength indication (RSSI) of the reference tags showed different patterns as the handheld reader was moved along the path. In addition, the polarization of the reader antenna also affected the detection of the reference tags. It was proven that the RSSI patterns of various reference tags at each handheld reader's location can be applied for reader's localization both for the cases with null or main lobe pointed toward the wall with reference tags attached.