The performance of passive UHF RFID tags, commonly available in the market, is significantly degraded when they are placed near a conducting surface. A possible solution to overcome this problem is to design tags based on PIFA (Planar Inverted F Antenna) the performance of which is less sensitive to the presence of objects in its surroundings. This ability is mainly due to the existence of a ground plane inherent to its structure. In this paper, a PIFA is utilized in the design of a passive tag that can be used to identify metallic objects with medium to large dimensions. A new type of antenna feeder is presented with a slot in the radiating element where the RFID IC is attached. The maximum range of utilization, covering all licensed RFID UHF bands (860 to 960MHz), is in excess of 8m, according to simulations using a MoM based software, verified by practical measurements. Further results from simulation and measurements show that the tag can also be used attached to other materials with good performance.
展开▼
