Patch antenna with EBG ground plane and two-layer substrate for passive RFID of metallic objects

Development of radio frequency identification (RFID) systems has increased rapidly in recent years. In many RFID applications, metallic objects need to be identified. However, generally used label-fabricated RFID tags do not work attached to metal. Therefore new antenna designs that can be mounted on metallic objects have to be developed. We present and discuss the development and performance of a patch antenna with an EBG ground plane and a two-layer substrate (on each side of the ground plane) for passive RFID tag applications. This antenna design is mountable on metallic objects and can be used in RFID tag antenna applications. The antenna is compared with a similar patch antenna with regular ground plane. A smaller patch size can be achieved with the EBG ground plane. Experiments show that both designs are mountable to metal without degeneration in their performance.