Research And Design Of Multi-band Planar Antennas For LTE Mobile Devices

With the rapid development of wireless communication technology,mobile phone plays an increasingly important role in our daily life.As a crucial part of mobile devices,antenna directly affects the overall performance of mobile phones.Small,light-weighted and full networks fitted,globalization have become the trend of mobile phone,which requires the mobile phone antenna covering more bands in a smaller space.How to design a multi-band mobile phone antenna in the limited space with excellent performance has become a difficulty.In this thesis,the trend of multi-band and miniaturization technology of mobile phone antennas has been studied and analyzed.The paper introduces the research background and significance as well as the status at the very beginning.Then the basic of theory of antennas for mobile devieces,as well as the popular motheds of multibanded,miniaturization and widbanded are briefly discussed.Finially,according to requirements the current 4G mobile phone,three mobile phone antennas with different structures are designed.The first one is a planar monopole antenna printed on a single plane.By using the couple-feded method and C-shaped groud plane,the antenna covers nine operating bands including LTE700/2300/2500,GSM850/900,DCS1800,PCS1900,UMTS2000,WLAN-2400 with the VSWR<3.The second antenna is an antenna with hybrid structure designed with a noval strategy.The low frequency bandwidth is generated by a L type high pass matching circuit,while the middle and high frequency bandwidths are generated by self-resonant of antenna structure.It ables to cover LTE700/2300/2500/3500,GSM850/900,DCS1800,PCS1900,UMTS2000,WLAN2400 bands.The third antenna is a multi-band MIMO antenna with two identical radiators,each occupy an area of 33mm×10mm×0.8mm.It covers of the 4G LTE700/2300/2500 bands,as well as most of 2G and 3G bands.By placing the two antenna elements on the top and bottom edge of the substrate and introducing slip on the groud,the isolation achieved is better than 15 dB over low band and 18 dB over high band.These three antennas were mannufatured and the bandwidth,efficiency,radiation patterns,isolation were tested.The test results are in accordance to the simulation results in HFSS.In the end,the work of the thesis is summarized,and the deficiencies is also pointed out.