A compact cavity-backed monopole antenna for UWB applications

A new directive ultra wideband (UWB) antenna using a cavity-backed monopole is presented. This compact, broadband, and high-gain antenna consists of a triangular-shaped monopole radiating element along with a tapered cavity. The proposed design uses two pairs of shorting lines to improve radiation pattern consistency at higher frequencies and a tapered cavity to enhance the gain and impedance bandwidth of the antenna. Electromagnetic simulations show an impedance bandwidth with voltage standing wave ratio (VSWR) < 2 from 3.0 GHz to 14.5 GHz (133%) and a gain greater than 6 dBi from 3.0 GHz to 10.8 GHz (113%) with a peak of 10.8 dBi. The proposed antenna is relatively compact with overall dimensions of 0.65λl × 0.32λl × 0.18λl, where λl is the free-space wavelength of the lowest operating frequency.