A DUAL-BAND UHF PASSIVE CMOS RFID TAG WITH AN EASILY MATCHED CHARGE PUMP

摘要

This paper presents a dual-band CMOS 15-bit passive UHF RFID tag chip. The tag is applied in the UHF RFID indoor localization system. Our design employs dual-band communication links that include the power link (925/866 MHz) and the data link (433 MHz). In the real application, the tag can be either far away or be close to the reader, so the tag has to be sensitive and sturdy enough to the wide input power range. Hence, the tag has been carefully designed especially for the case of high input power. Also, the tag employs two stages of limiters to replace the bandgap reference circuit. Another critical characteristic of the tag is that we use multi-stage voltage doublers in the charge pump. This makes matching between the tag and the antenna easily. Therefore, it read range is wider than reference paper [1]. The power link's power range can achieve -24.2 dBm ～ 18.7 dBm. The data link's power range can achieve -41.2 dBm ～ 14.2 dBm. The proposed RFID tag is fabricated in TSMC 0.18 μm mixed signal/RF 1P6M CMOS process.