UHF RFID Tag Antenna Mounted on Metallic Objects

A deployment method by changing the gap between a tag antenna and a metallic plate is given to reduce the metal effects on antenna. Pad some medium into the gap, and then integrate. By the adjustment of the gap´s thickness, the reflection of the electromagnetic wave is full used to improve the antenna´s gain and field strength. Thus may result in great read range. Finite element method (FEM) is used to simulate the tag´s performance. Theory analyses are also given. With this method, the high performances of the tag can be available even in metal environments.