Dual band-notched small monopole antenna with novel W-shaped conductor backed-plane and novel T-shaped slot for UWB applications

In this study, a novel method for designing a new monopole antenna with dual band-notched characteristic for UWB applications has been presented. The proposed antenna consists of a square radiating patch with a modified T-shaped slot, and a ground plane with two E-shaped slots and a W-shaped conductor backed-plane. By cutting two E-shaped slots in the ground plane, additional resonance is excited and hence much wider impedance bandwidth can be produced, especially at the higher band, which results in a wide usable fractional bandwidth of more than 130% (2.73%13.3 GHz). In order to generate single band-notched characteristic, the authors use a W-shaped conductor backed-plane structure on the other side of the substrate. In addition, by cutting a modified T-shaped slot in the radiating patch and microstrip feed-line, a dual band-notched function is achieved. The measured results reveal that the presented dual notch band monopole antenna offers a very wide bandwidth with two notched bands, covering all the 5.2/5.8 GHz wireless local area network, 3.5/5.5 GHz WiMAX and 4 GHz C bands. The designed antenna has a small size of 12 % 18 mm². Good voltage standing wave ratio (VSWR) 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 ultra-wideband (UWB) applications.