A Novel 5.5/7.5 GHz Dual Band-Stop Antenna with Modified Ground Plane for UWB Communications

In this study, a novel design of ultra-wideband (UWB) monopole antenna with extended bandwidth and dual band-notched properties is proposed. In the presented structure, by cutting two pairs of U-shaped slots in the ground plane, additional (third and fourth) resonances at 11 and 14 GHz are excited and much wider impedance bandwidth can be produced which provides a wide usable fractional bandwidth of more than 135 % (3–15.7 GHz). In order to generate a single band-notched characteristic, a pair of I-shaped conductor-backed plane was embedded in the antenna backside. Finally, by adding a pair of rotated T-shaped strips in the center of I-shaped structure, a good dual band-notched function is achieved. The measured results reveal that the presented monopole antenna offers a very wide bandwidth around of 5–6 and 7.25–7.75 GHz to suppress any interference from wireless local area network and downlink of X-band satellite communication systems respectively. The designed antenna has a small size of 12 × 18 mm 2 . Good return loss, antenna gain and radiation pattern characteristics are obtained in the frequency band of interest. Simulated and measured results are presented to validate the usefulness of the proposed antenna structure for UWB applications.