Compact Multi-resonance Monopole Antenna with Dual Band-Stop Property for UWB Wireless Communications

A novel design of ultra-wideband (UWB) monopole antenna with dual frequency band-notched property is proposed. The antenna consists of a square radiating patch with a hook-shaped slit, a feed-line, and a modified ground plane with an inverted anchor-shaped and a pair of inverted \(\Gamma \)-shaped protruded strips inside the rectangular slot. In the presented structure, by cutting an inverted T-shaped slit in the ground plane and also by converting this structure to the anchor-shaped slit, additional (third and fourth) resonances are excited and hence much wider impedance bandwidth, especially at the higher band can be produced which provides a wide usable fractional bandwidth of more than 130 % (2.8–13.3 GHz). In order to generate a single band-notched characteristic, we cut a hook-shaped slit at the radiating patch. Finally, by embedding a pair of protruded \(\Gamma \)-shaped strips inside the rectangular slot in the ground plane, a good dual band-notched function is achieved. The measured results reveal that the presented dual band-notched monopole antenna offers a very wide bandwidth with two notched bands, covering all the 5.2/5.8 GHz WLAN, 3.5/5.5 GHz WiMAX and 4 GHz C bands. The designed antenna has a small size of \(12\times 18\,\hbox {mm}^{2}\). 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.