Modes‐controlled slot antennas with frequency selective surface

This paper presents two designs of square‐ring slot antennas to suppress the 2nd and 3rd harmonics by involving a frequency‐selective surface (FSS) with square‐loop‐type and meandered‐dipole‐type elements. The transparency of the surface in the higher‐order mode makes the ground plane invalid, so that the harmonics cannot resonate and emit. The experimental results show that the FSS structure not only demonstrates band‐reject characteristics, but also well retains the antenna performances for fundamental‐mode operation. Moreover, with the square‐loop‐type lattice, the impedance bandwidth was increased by about four times as much as that of the reference antenna. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 47–49, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21256