Guest Editorial: Special Issue on IEEE RFID 2019 Conference

With the proliferation of the Internet of Things, there is an increased demand to enhance every day physical objects with sensors and communication abilities so that they can have digital counterparts (“digital twins”) in a connected world. While many solutions based on protocols such as ZigBee, Bluetooth, ANT, LoRa, LPWAN, NB-IoT, HaLow, etc. do exist, RFID technology presents a compelling alternative. Radio Frequency Identification (RFID) is a generic term for a variety of active and passive RF technologies. RFID transponders have varying degrees of sophistication and their design is often a tradeoff between functionality and cost. At one end of the spectrum, there are active RFID tags that offer on-board battery and memory, sensor integration, active RF transmitters and hence communication range up to kilometers albeit at increased costs. At the other end, passive and semi-passive RFID tags rely on a simple load modulation to backscatter ID and data back to the reader over several meters distance. Passive RFID tags, in particular, lend themselves well for applications needing large-scale, low-cost, automatic identification and are a good option for imparting digital identity to a host of physical assets. Industry alliances such as the NFC forum (for HF RFID) and the RAIN RFID alliance (for UHF RFID) have been formed to motivate and promote these efforts.