The Study And Design Of Multi-band Low-profile Omnidirectional Radiation Antenna

Multi-frequency and miniaturized antenna is necessary for the current rapid development of mobile communication.Conventional antenna-design has been unable to meet the increasingly complex market demand,so in view of the demand of the multi-frequency and miniaturization antenna,this paper proposes methods by adjusting dielectric constant to reduce the antenna size,and through theoretical analysis,software simulation and physical verification to further embody the feasibility of this method.The goal of this paper is to design a four-band antenna.The center frequencies are 900 MHz,1800 MHz,2400 MHz and 3500 MHz,covering common mobile communication frequencies.In above research goal,the content as following:First,the paper propose the concrete research plan and the research,based on the summarization of the research progress at home and abroad,and various forms of antenna research;Second of all,the paper introduces the basic theory and experiment method for multi-frequency antenna,mainly including the antenna's main specification and test methods,such as reflection coefficient S₁₁,VSWR,pattern,etc.Third,this paper research and design a PIFA?Planar Inverted F-antenna?,which using the air medium,through HFSS simulation and physical experiment to determine the structural parameters of the antenna.The performance of the antenna is achieved,the design pattern antenna specification meets the target of VSWR less than 2,and antenna gain is greater than 1 dBi;Fourth,through the study and research of printed PIFA,puts forward three kinds design scheme of the printed PIFA,and by using HFSS simulation to analyze the characteristics of ant-specification,and according to the simulation of surface current their working mechanism are analyzed.Finally,the paper confirms the PIFA printed on the material specification is the best when the relative dielectric constant is 4.4,and the specification about VSWR can reach 1.4,the antenna gain can be up to 2 dBi.In this paper,the designed antenna has the characteristics of low profile and multi-band,and performance is outstanding.The method can effectively guide design of the multi-frequency antenna in mobile communication system.