A Composite Right/Left-Handed Transmission Line-Based Reconfigurable Antenna for UHF RFID Applications

Recently, internet of things (IoT) has caused revolution in almost all walks of life. As a critical object detection, identification, and sensing technology of IoT, radio frequency identification (RFID) has been treasured as the interface between the digital and physical world [1]. As the key component of RFID, RFID reader antenna is facing many challenges which restricts the development of RFID and IoT. First, the small and single coverage zone limit the application scenarios of RFID [2]–[3]. Moreover, there is a research blank of frequency reconfigurable RFID reader antenna, which is treasured because it can free the frequency band limit of RFID reader without violating different countries' RF policies and increase the information diversity in RFID sensing systems.