Research And Design Of Terminal Antennas In Full Metal Housing Devices

With excellent appearance and high mechanical strength,full metal housing(FMH)terminal devices are more and more popular,and have become a trend of appearance design.However,full metal housing has a bad effect on antenna's performance,especially causes antenna's narrow bandwidth and low efficiency.So,it is difficult to design a good performance antenna in FMH device.Based on some documents,this paper does some researches to solve these problems mentioned above,and designs four terminal antennas in FMH environment.Firstly,a mobile phone antenna design in full metal back cover is proposed in this paper.A slot mode and two PCB modes are involved to radiate electromagnetic wave in this design,and two tunable circuits are added to realize the low-band's and high-band's frequency reconfiguration respectively.The frequency band that covers six WWAN bands can be widened by this method.Besides,all bands'efficiencies are more than 30%,which have good radiation performance.Secondly,some researches on antennas in FMH tablet computer are done in this paper,and the idea of using the cavity consisted of FMH and PCB is proposed.By combining antenna's modes and cavity modes,three antennas are designed in FMH tablet computer.The first one is a monopole antenna that has three resonant modes including antenna self-mode in 5.5GHz,characteristic mode in 1.575GHz and cavity mode in 2.45GHz.By this method,this antenna can cover GPS/WLAN a/b/g bands.Besides,this antenna size is only 6×7mm~2,which is very small for terminal antennas.The second one is the form of a?/4 loop antenna which has five resonant modes.There are three antenna's self-modes,including?/4 mode,3?/4 mode,?mode.And,two cavity modes can also be excited by the coupled feed strip.All these five modes can cover multiple frequency bands.The last antenna is mainly used to do some research on how to apply cavity antenna to MIMO system.This antenna combined by loop antenna's self-mode and cavity modes can cover WLAN a/b/g bands.In addition,this design also proposes the methods of adding shorted vias and decoupling strip to achieve high isolation,which is useful to the research of MIMO antenna in FMH environment.