Achieving Ratio Bandwidth of 25:1 From a Printed Antenna Using a Tapered Semi-Ring Feed

A printed super-wideband (SWB) antenna that consists of an elliptical monopole and a trapezoid ground plane is presented. By introducing a tapered microstrip impedance transformer and implementing a semi-ring feed interface to the radiation patch, the bandwidth of the antenna is enhanced. The results demonstrate that the measured 2:1 VSWR bandwidth is from 1.08 to 27.4 GHz with a ratio bandwidth of 25:1. The antenna has a stable radiation pattern over this frequency band. It is suitable for wireless communication applications.