A Horizontally Polarized Rectangular Stepped Slot Antenna for Ultra Wide Bandwidth With Boresight Radiation Patterns

In this paper, a horizontally polarized UWB antenna is proposed. The UWB nature of the antenna is achieved using a stepped impedance microstrip feed line to excite the stepped slot configuration. The -10 dB experimental impedance bandwidth acquired from VNA is 10 GHz (from 3.2 GHz to 13.2 GHz) which is 122% at the center frequency of 8.2 GHz. Symmetric feeding of the slot ensures good polarization characteristics and uniform radiation patterns throughout the operating band. The measured co to cross polarization ratio in boresight direction is around 15 dBi over most of the frequencies while the average peak gain is around 5 dBi. With the help of parametric studies, the choice of the antenna dimensions is justified. Finally, a modified design with band-notch characteristics to suppress interference from 5 GHz WLAN systems is presented. The simulated and measured results are in good agreement.