| With the rapid development of mobile technology,mobile phones are moving towards full screen,thin and light,and multi-function.Mobile phone antenna design requirements are also getting higher and higher,requiring mobile phone antenna design to be miniaturized.In the design process,sufficient clearance area needs to be reserved to ensure that the antenna has good radiation efficiency,and the antenna radiation unit structure cannot take up too much PCB board space.At the same time,reducing antenna coupling on the basis of achieving miniaturization is also an important factor for designing MIMO antenna design.Therefore,designing a mobile phone antenna suitable for ultra-thin,full-screen smart phones is a difficult problem in the design of mobile phone antennas.The innovations and main contents of this article are as follows:In the first part,this paper proposes a two-element MIMO antenna,using ceramic material as the carrier of the antenna radiating end.Through simulation experiments,the structure size of the antenna radiating unit after adding the ceramic carrier can be reduced by about 20%.Compared with the antenna structure in the literature,the antenna size can reduce the antenna space design size by about 30%.The antenna can cover GSM900,PCS1900,DCS1800,LTE1900 and other frequency bands.The antenna simulation results have higher radiation efficiency and gain,and the antenna's omnidirectionality and low coupling better meet the design requirements.The XFDTD software simulates the radiation absorption rate of the antenna to the human body,and the simulated human head radiation index meets the standard of less than 1.6W / kg.In the second part,this paper proposes a four-element MIMO antenna to make its working frequency band cover the N78 frequency band.The antenna design is composed of a circular slot structure,a microstrip line structure and a slot structure.The low-profile characteristics and slot slot structure can reduce the space size of the radiation unit.The characteristics of adding a circular slot structure and a slot antenna can effectively reduce antenna port coupling and improve antenna isolation.The good radiation characteristics and omnidirectional characteristics of MIMO antennas can meet the requirements of antenna design indexes.In the simulation process,because there are many feed ports,the simulation speed is slow.In order to solve this problem,this paper proposes to apply the particle swarm algorithm to solve the simulation efficiency problem of multi-port antennas.The simulation platform is built by the simulation software HFSS and MATLAB.Conduct joint simulations to reduce the simulation time of antenna radiating elements.The antenna has passed processing to test its passive parameter performance.The antenna's passive parameter performance index is good and meets the antenna index requirements.Using XFDTD software to simulate the radiation absorption rate of the antenna to the human body,the antenna meets the standard of less than 1.6W/kg on the human head radiation index SAR. |
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