A Compact Design and New Structure of Monopole Antenna with Dual Band Notch Characteristic for UWB Applications

摘要

In this paper, a compact design and new structure of monopole antenna with dual band notch characteristics for UWB applications has been presented. The antenna consists of a triangular patch with C-shaped slot, two L-shaped and one split ring shaped parasitic backplane elements structure. By inserting three slots in the rectangular truncated ground plane as defected ground structures (DGSs), much wider impedance bandwidth can be produced, and moreover to improve the input matching quality of the antenna at all its operating bands which are spread in a vast frequency range, a modified stepped feed-line is employed. These changes much improves the antenna's impedance bandwidth by 112% which covers the entire UWB bandwidth range. In order to generate single band notch characteristic, split ring shaped parasitic element backplane structure is utilized on the ground plane side of the substrate. In addition, by etching a C-shaped slot on the radiating patch, a dual band notch function is achieved. The measured frequency results show an impedance bandwidth of 3.15-10.78 GHz for a Voltage Standing Wave Ratio (VSWR) less than 2 with two eliminated bands placed at 3.49-3.81 GHz (320 MHz, 8.8%) and 5.24-6.22 GHz (980 MHz, 17%), which reject the WiMAX band, and Wireless Local Area Network (WLAN) band, respectively. A prototype was fabricated and measured based upon optimal parameters and experimental results show consistency with simulation results. The measured radiation patterns of proposed antenna for most frequencies are omnidirectional and this antenna as wide impedance bandwidth.