A Study And A Design Of Band-notched UWB Antenna

With the rapid development and wide application of ultra-wideband (UWB) techonlogy,UWB antenna becomes one of the hottest topics in the research of wireless communicationsystem. Due to its broad-covered frequency range, UWB communication system mayinterference with pre-existing communication system such as WLAN and WIMAX anddeteriorate the quality of communication. Therefore, it is urgent to introduce a stopband toUWB antenna to restrain the potential interference between UWB communication system andnarrow-band communication system. This paper is focuses on design theory and realizationmethod of traditional UWB antenna and UWB antenna with notched band. The main tasksinclude:First of all, a hexagon-shaped UWB antenna and a fan-shaped antenna is proposed forUWB system. The design theory of the antennas are given and the properties of the antennasare analyzed. Then a printing monopole circular UWB antenna is presented. In addition, aprinting monopole semi-circular UWB antenna is designed. The simulation results show thatall these designs satisfy the requirement of UWB communication system.In the second place, the design theory and implementation technique of UWB antennawith notch band by cutting slots on the radiating element of monopole antenna is given. Slotson the radiating element will alter the current distribution on antenna’s radiating element anda notch band can be achieved. The size of the slot on the patch determines the position ofstopband. The designed UWB antenna produces band-notched characteristics in the frequencyrange of5.2GHz to5.8GHz, which effectively separates the interference of WLAN system.Having the merits of small volume and being apt to realize, this method realizes band-stopcharacteristics without expanding the size of the antenna.At last, UWB antennas with notched band are proposed by loading stubs. Stubs areloaded inside and outside of the radiation patch of UWB antenna, notch band can be obtainedin the antenna while keeping the characteristics of the passband. External resonators areloaded to the feed line of the antenna to achieve a stopband in the UWB band, which hassmall influence on the radiation characteristics of the original antenna. The position andbandwidth of stopband can be controlled by adjusting the loaded elements. Experimentalresults show that UWB antenna’s working frequency range are3.1GHz-10.6GHz), whichcovers UWB communication frequency range while effectively reducing interference betweensystems.