Enhanced Bandwidth Ultra-Wideband Small Monopole Antenna with Variable Band-Stop Function

In this paper a novel ultra wideband monopole antenna with frequency band-stop performance is designed and manufactured. The proposed antenna consists of square radiating patch with a T-shaped ring slot and ground plane with two G-shaped slots. In the proposed structure, by cutting two G-shaped slots in the ground plane, additional resonance is excited and hence much wider impedance bandwidth can be produced, especially at the higher band. In order to create band-rejected function we use a T-shaped ring slot in the radiating patch. The fabricated antenna has the frequency band of 2.95 to over 15.65 GHz with a rejection band around 5.13-5.91 GHz. Good return loss 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.