Design Of Multiband And Wideband MIMO Mobile Phone Antennas

MIMO(Multiple-Input Multiple-Output)is a key technology in 4G.In the future 5G communication,it is still an indispensable protagonist.However,with the restriction of the space of a mobile terminal,some difficulty need to be overcome in current MIMO antennas,such as placing more antennas,achieving wideband and ensuring high isolation between antennas.Therefore,the design of multi-band and wideband MIMO antennas for mobile terminal has great practical significance.This thesis focus on the research of mobile phone antennas,including two design of wideband and multi-band MIMO mobile phone antennas,the main work are summarized as follows:Firstly,a novel broadband 4x4 MIMO antenna for mobile phone is designed.The antenna system consists of four identical PIFA antenna elements distributed across the four corners of the FR4 substrate.In order to improve the isolation between antenna elements,the decoupling measure is adopted by merging the ways of adding parasitic strips,slotting on the metal ground and protruding T-shaped branches.In addition,the parasitic unit does not increase the size of the antenna itself.The measured results show that the operating bandwidth includes DCS 1800,PCS1900,UMTS2100,LTE2300,LTE2500 and 2.4 GHz WLAN bands w,ith the return loss better than 10dB and the isolation more than 14dB.The symmetry of the measured radiation pattern and the calculated low ECC(Envelope Correlation Coefficient)confirm that the antenna system has good diversity performance.Secondly,a planar monopole MIMO antenna for 4G/5G is designed.The antenna consists of two 4G antenna elements and four 5G antenna elements.The 4G antenna can cover GSM850/900,DCS1800,PCS1900,UMTS2100 LTE2300 and LTE2500 bands when the return loss are better than 6 dB and the isolation are more than 10dB.In addition,the S12 is less than-15 dB in the upper band.The 5G antenna can cover the 3300-3600 MHz band while meeting the return loss better than 10 dB and the isolation more than 12dB.Low values of the ECC also indicate that the antenna system can obtain a high diversity gain.Therefore,the design of the antenna system has a wide application prospect.