A new RFID architecture based on multi-port reflectometer

The reader of the passive radio frequency identification system (RFID) is proposed based on automatic network analyzer (ANA), commonly used to measure the complex reflection coefficient (CRC) of microwave devices. This architecture of the reader allows one to overcome the main problem of passive RFID, namely, the signal of the reader transmitter penetration into its receiver that blocks the weak signal of a radio tag. A vector ANA based on a direct frequency down-conversion of the output signals of combined multi-port reflectometer (MR) measuring ports is proposed for use in the reader of a passive RFID system. Optimal algorithms for estimating the unknown module and phase of the radio tag signal as well as gains of the measuring channels of the proposed RFID reader are developed, which ensure high accuracy, reduce random measurement errors and basic systematic calibration errors. The experimental setup design of the combined MR is described. The results of the RFID system simulation are presented.