Tag Size Matters: Miniaturized RFID Tags to Connect Smart Objects to the Internet

State-of-the-art passive RF identification (RFID) technologies are used in contactless smart cards and item management. These technologies rely on the radio communication between an RFID reader and batteryless (or passive) RFID transponders (tags) and thus allow a low-cost, unique identification of objects. Current research topics in the field of passive RFID technologies focus on activities that go beyond the ID in RFID [1]. Research in the microwave community is focused on developing miniaturized passive RFID sensor tags. Tags of this kind constitute inexpensive, long-lasting, ubiquitous sensor units with unique identifiers and make it possible for smart objects to connect to the Internet. In particular, such miniaturized sensor tags enable the identification and monitoring of small objects (e.g., documents, jewelry, medicines, and diagnostic devices) that can then become part of the Internet of Things (IoT) [2].