Study On Band Broadening And Band Notched Chararacteristic Of Ultra-Wideband Planar Printed Antenna

Ultra-wideband (UWB, Ultra-wideband) technology is a new wireless communication technology. It has solved several major problems of traditional wireless transmission technology for many years due to their merits such as insensitive to fading channel, high data rate, low capture ability, small emission power, low system complexity, providing position accuracy of a few centimeters. UWB technology is widely used in radar imaging, positioning, distance measurement, communications, and other fields. At the same time, UWB antenna is an essential part, which directly affects the quality of the entire communication system. Therefore, it is a challenge to research the UWB antenna.First, the paper describes the characteristics and applications of UWB technology, band-expanded technique and band-notched technology. Then, ultra-wideband antenna’s basic theory, analytical methods, and technical requirements are introduced respectively. Finally, the planar printed monopole and slot antenna for the short-rang communications applications are researched and discussed through the electromagnetic simulation. The paper mainly doses the following work:1. The bandwidth of antenna impedance is expanded greatly by processing the gradient structure on the ground of planar printed monopole, the frequency band of VSWR<2is2.89-12.00GHz.2. A band-notched planar printing monopole having double "L" slot is proposed and optimized for UWB applications. It has the band-notched characteristic at5-6GHz in order to prevent the UWB antenna to transmit/receive the signal of the WLAN frequency band.3. The radiation patch of printed slot antenna fed by CPW is optimized to achieve the band-expanded characteristic due to good impedance match with the ground. The impedance bandwidth of VSWR<2is3.02-11.65GHz.4. The band-notched printed slot antenna is proposed and optimized. The band-notched characteristic is achieved by slitting double inverted U slot on the radiation patch and it has the band-notched characteristic at5-6GHz and7.7-8.5GHz, respectively.