Dome-Shaped Ellipsoidal Reflector Antenna for UHF-RFID Readers With Confined Near-Field Detection Region

This letter proposes and demonstrates the concept of ellipsoidal reflector antennas for radio frequency identification reader applications at UHF band. The antenna can be potentially integrated with environmental structures to confine the reader detection region. The energy bounding characteristics result from the dual-focus feature of an ellipsoidal reflector in its near-field region, as the feed located at one of the two foci can create a focused field distribution around the other focus. An axial energy focusing is, thus, formed to confine the energy in a restricted region (near-field beam focusing), also minimizing the interference effects outside of the targeted area. Both numerical simulations and experimental results are presented to demonstrate the feasibility of this antenna concept.