A planar circular ring ultra-wideband antenna with dual band-notched characteristics

A compact planar monopole ultra-wideband (UWB) antenna with dual band-notched characteristics is proposed in order to minimize the interference between UWB systems and existing world interoperability for microwave access and wireless local area network operating bands. The antenna has a microstrip line-fed circular ring radiator with one etched partial concentric annular slot and one semi-circular slot. Two rectangular slots are also etched to connect the slots to the outer and inner periphery of the circular ring radiator. The desired dual band-notched UWB operation can be obtained by choosing the size and location of the etched slots. Experimental results show that with a compact size of 24 mm × 26 mm the proposed antenna achieves a wide impedance bandwidth from 2.79 to more than 11 GHz with two frequency notched bands of 3.3–3.8 and 5.1–6 GHz for WiMAX and WLAN, respectively. Moreover, the antenna exhibits stable radiation characteristics and a good time domain behavior which makes it suitable for being used in the future UWB applications