Planar UWB Antenna with WLAN/WiMAX Dual Band-notched Characteristics Using the Hilbert-curve Slots

In this paper, a compact ultra-wideband (UWB) antenna with dual band-notched design is proposed. The antenna consists of a rectangular metal patch and a 50 ohm coplanar waveguide (CPW) transmission line. By etching both the first iteration and the third iteration Hilbert-curve slots on the radiating patch, band-rejected filtering properties in the WiMAX/WLAN bands can be obtained. Furthermore, each notched band can be easily tuned by adjusting the length of each Hilbert-curve line segment because the sum of whole line segment controls the corresponding resonance frequency. The proposed antenna is simulated, designed, and measured showing a broadband matching and a stable radiation performance over the entire UWB frequency range, which prospects the deployment in the UWB system. As will be seen, the operation bandwidth of the antenna is from 2.5 to 10.6 GHz for VSWR < 2, in which two frequency rejection bands from 3.3 to 3.7 GHz and from 5.4 to 6 GHz for VSWR > 2 can be achieved. The measured results agree well with the simulation by the Microwave Studio of the CST. Based on the simulated and measured results, the newly proposed antenna by this paper can be found its application on the design of multi-band rejection characteristics with broadband antenna technology.