Planar antenna for passive radio frequency identification (RFID) tags

The paper presents an overview of recent state of the art in antenna technology for passive RFID tags used for field and asset tracking. Improved detection ranges have been realised utilising planar antenna technology with the benefits of low-cost, ease of manufacture and low-profile. These are offset by the disadvantages of narrow bandwidth and low power capacity. Improvements in passive RFID tag antenna design operating at the ultra high frequency (UHF) and microwave frequency bands are detailed and discussed. Numerical results are calculated using CST microwave studio