Research And Design Of Small-size Coupled Feeding Multi-band 4G Mobile Terminal Antenna

Mobile technology has developed rapidly.From the 1980s,it has experiencedfirst-generationanalogvoicesystem,second-generation narrowband digital voice system,and reached the third and fourth generation mobile communication?3G,4G?.Then it goes foward to the Fifth-generation mobile communications?5G?direction gradually.Each generation system has different communication bands.This requires the phone antenna to cover as many frequency bands as possible so that the phone can switch between the various frequency bands.Firstly,a small-size coupled-fed planar inverted-F antenna for eight-band operation in the mobile phone is proposed and discussed.It can cover813-1072 MHz and 1570-2690 MHz,two wide frequency bands.It occupies only 11×30×5 mm³area,but realizes the eight bands covered,thus realizes the miniaturization and multi-band at the same time.Then,a multi-band printed loop mobile phone antenna for GNSS application is presented,which occupies a small volume of 18×32×3 mm³and has two wide bands of821MHz-1012MHzand1375MHz-2937MHz.Theantennacovers LTE/WWAN bands?VSWR<3?and GNSS band?VSWR<1.5?.Next,asmall-sizeandhigh-isolationMIMOantennawith magneto–dielectric material for smartphone application is proposed.Antenna unit adopts the planar inverted F structure.The volume of the MIMO antenna is only 66 mm×15mm×4 mm,which covers the 2G/3G/4G multiple frequencies.And the coupling is below-10 d B across the entire operational bandwidth of the antenna.Finally,a Ni Zn ferrite thin-film MIMO mobile phone antenna is designed.It is different from the traditional ferrite antenna,which relies on ferrite for its high dielectric constant and high permeability to make antenna small.The ferrite thin film of this antenna is used as an absorbing material for improving the isolation of the MIMO antenna.The application of the ferrite thin film makes the S₁₂2 of whole working bands of the antenna less than-10d B so that the isolation meet the requirements.