Bandwidth Enhancement and Miniaturization of Fork-Shaped Monopole Antenna

A small, extremely wideband fork-shaped monopole antenna with a new modified design of ground plane is presented. By connecting an asymmetric T-shaped patch loaded by a horizontal stub to the ground plane, not only the lower edge of the bandwidth (BW) is considerably decreased from 3.6 to 1.95 GHz, but also the impedance matching at the higher frequencies is much improved, and therefore total BW is extremely enhanced from 82% to 164%. By using these features, a miniaturized sample of the antenna with an area reduction of about 57% and BW increment of about 34% is also designed and presented. The measured results of the first and second antennas show the acceptable radiation characteristics with the BWs from 1.95 to 19.9 GHz (164.3%) and from 3.5 to 13.1 GHz (116%) for VSWR <; 2, respectively.