Orthogonally proximity-coupled patch antenna for a passive RFID tag on metallic surfaces

A new wideband rectangular patch antenna for radio frequency identification tags mountable on metallic surfaces is presented. An orthogonally proximity-coupled feed structure, in which the direction of the microstrip feedline is orthogonal to that of the resonant length of the radiating patch, is explored to perform simple and wideband impedance matching between an antenna and a tag chip without any additional matching networks. The proposed antenna has wideband characteristics and good cross-polarization, which are validated by simulations and measurements. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 715–717, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22222