Design of Tri Notched Ultrawideband Antenna Using U Slots and EBG Structure

A circular ultra-wideband monopole antenna with triple band notch features has been designed and presented in this research article. The proposed antenna exhibits band elimination characteristics for three different narrowband applications, i.e. C-band satellite downlink band (3.7 GHz to 4.2 GHz), unlicensed WLAN frequency spectrum (5.47 GHz to 5.85 GHz), and downlink frequency spectrum (7.25 GHz to 7.75 GHz) for X-band satellite communication. Two U-shaped slots have been integrated into the radiating element with a mushroom nature of Electromagnetic Band Gap (EBG) structure of square shape positioned next to the feedline of the reference antenna. This integration produced the desired notching effect. The proposed design efficiently covers the ITU-specified UWB spectrum (3.1 – 10.6 GHz). The gains at the notched frequencies are well below the reference antenna and about −6 dB has been achieved at −3.95 GHz. The pass-band radiation characteristics indicate the usefulness of the design. The proposed antenna structure measures only $\boldsymbol{0.28 \lambda}\times \boldsymbol{0.3\lambda}\times \boldsymbol{0.014 \lambda}$ where $\lambda$ corresponds to the highest operating wavelength.