Research On The UWB Antenna Integrated With Stop-Band Filters

With the development of modern science and technology, modern communication miniaturization is more popular for People's requirements. In order to miniaturization,integrating design of RF front-end has become a boom in academia and industry. Especially,ultra-wideband technology excellent development since federal committee author UWB from 3.1 GHz to 10.6 GHz for commercial in 2002. UWB technology has many advantages,such as high transfer rate, high security, resistance to multipath fading ability and so on. However,since the ultra-wideband covering 3.1?10.6GHz frequency band is very wide which easily interfered by many narrowband communication systems shared with UWB band, such as Worldwide Interoperability for Microwave Access (WiMAX, 3.3-3.6 GHz), Wireless Local Area Networks (WLAN, 5,15?5.35 GHz, 5.725?5.825 GHz), Radio Frequency Identification(RFID, 6.8 GHz) and X-band satellite communications system. In this paper, ultra-wideband antenna integrated with stop-band filter is design, which has a good filtering characteristic,and,hence it is meaningful to improve the ultra-wideband communication system anti-interference capability. The detail of design as follows:Firstly, stop-band filters using defected microstrip structure are design to filter out the unexpected narrow-band interferences. In this paper, three kinds of stop-band filters were given. At the beginning, a single stop-band filter is using DMS, which center frequency located at 3.42 GHz to filter out the narrowband interference of WiMAX. Next, two DMSs based on cascade technology to obtain dual stop-band filter, the center frequencies locate at 3.52 GHz and 5.3 GHz. The simulation results show that the dual stop-band filter can filter out WiMAX and WLAN narrowband communications system. Finally, triple DMSs are used to obtain triple stop-band filter. The triple stop-band filter can filter out interference from WiMAX, WLAN and RFID narrowband communication system. In addition, equivalent circuit method is utilized to analysis the design of three stop-band filters to verify the correctness and validity of simulation design. The compare of HFSS and ADS results verify the correctness and effectiveness of design.Next, UWB antenna integrated with stop-band filter is proposed without change the radiating element shape and structure, that is stop-band filter integrated in UWB antenna feed line to obtain band-notched antenna. Firstly, bandwidth UWB antenna is proposed using etch angle and notch on radiation patch. Then, the UWB antenna integrated with single stop-band filter, dual stop-band filter and triple stop-band filter, respectively. A band-notched antenna with good filtering characteristics is obtained. Meanwhile, analysis all of the design antenna using equivalent circuit approach to obtain the equivalent circuit.Finally, a five band-notched antenna is obtained using double U-shaped resonator and integrated dual stop-band filter in feed line. The finite element method is utilized to verify the effectiveness and feasibility of the design. The simulation results show that the proposed band-notched antenna can filter out S-band, WiMAX, C-band, WLAN and ITU interference system in UWB band.