A Planar Folded Ultrawideband Antenna With Gap-Loading

A novel ultrawideband planar gap-loaded folded antenna is proposed in this paper, which is derived from an ordinary three-wire folded antenna with the gap-loading technique. The fabricated monopole antenna has a small electrical size and a measured bandwidth of 8.8:1 ranging from 1.48 to 13 GHz. The operating principles of the proposed antenna, including the excitation of three main resonant modes and their effects on the return loss, are analyzed. The proposed antenna exhibits a relatively stable radiation pattern, as proved experimentally in the paper. In the end, the parametric studies are performed for practical applications