| One of the components used to receive and transmit radio waves in a wireless communication system,the quality of its performance will directly affect the communication quality of the whole communication system.In recent years,based on people's requirements for the energy radiation efficiency of the channel capacity in the communication system,the importance of wide-band miniaturized antenna research is becoming more and more important.The non frequency antenna can achieve the characteristics of the broadband band,the concept was put forward by V.H.Rumsey in 1957.This concept has made a major breakthrough in the development of the antenna,the bandwidth can be extended to 40 to 1.Until then,the bandwidth of an antenna with wideband directional and impedance characteristics is not more than 2 to 1,logarithmic periodic antenna is a typical non frequency antenna.The structure of the logarithmic periodic antenna has been greatly developed since its birth.The logarithmic periodic dipole antenna appeared in 1960,it has been widely used because of its excellent antenna structure and electrical characteristics.But because the frequency of the ultra-short wave band is low,the wavelength is longer.So the miniaturization of the antenna is critical.There are many technology which is loading antenna,additional active network and fractal structure at home and abroad.The article is designed a miniaturized VHF log-periodic antenna.Although the VHF has benn widely used in the land navigation communication system,and the antenna technology is relatively mature,but miniaturized and directional antenna is relatively less.Therefore,this paper select log-periodic dipole antenna.Firstly,calculating gain and direction by Ansoft HFSS and optimize many times.Secondly,designing the loading network by Advanced Design System 2009.Finally,the antenna is fabricated and measured.The ideal design target is realized,and the antenna prototype is made,and the index requirement within the working band is realized. |
PDF Full Text Request