Novel Design of Dual Band-Notched Monopole Antenna With Bandwidth Enhancement for UWB Applications

This letter proposes a novel printed monopole antenna for ultrawideband applications with dual band-notched function. The antenna consists of a square radiating patch with an inverted T-shaped ring slot, surrounded by a C-shaped slot, which provides a wide usable fractional bandwidth of more than 125% (2.71-12.06 GHz). In this structure, by cutting an inverted T-shaped slot, the impedance bandwidth is effectively improved at the upper frequency. In order to generate single band-notched characteristics, we use an inverted T-shaped slot, surrounded by a C-shaped slot, in the radiating patch. By adding an inverted T-shaped parasitic structure inside the inverted T-shaped slot on the radiating patch, a dual band-notched function is achieved, and also by inserting this parasitic structure, additional resonance is excited, and hence much wider impedance bandwidth can be produced, especially at the higher band. The measured results reveal that the presented dual band-notch monopole antenna offers a 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 × 18 × 0.8 mm3.