Research And Design Of Multibands Miniaturization Omnidirectional Microstrip Antenna

Antenna as an important part of the wireless terminal,responsible for the terminal and the base station between the information exchange.With the development of wireless terminals tend to multi-functional and portable,its built-in antenna requirements become more stringent:having multiple operating frequency bands,small size and good omnidirectional radiation and so on.Due to its own advantages,micro-strip antenna can fully meet the above requirements.In this thesis,the present situation and application background of micro-strip antenna are introduced,and the research status of miniaturization and multi-band technology is summarized.The theoretical analysis and numerical calculation method of micro-strip antenna design are described,and the miniaturization and multi-frequency technology of micro-strip antenna are summarized.On the basis of this,this thesis first designs the monopole micro-strip antenna with double radiator,and uses the asymmetric umbrella distribution structure to realize the three operating frequency bands and omnidirectional radiation.Then,the meander line technology is used to miniaturize the radiation.The size and the curvature of the meander line are simulated and analyzed.Finally,the area of antenna is reduced by 66%.And then the introduction of short-circuit grounding metal band to correct the three resonant frequency of the antenna,and finally by adding a parasitic patch on the ground plate greatly optimized the high frequency band at the return loss.The total area of the PCB is 54 × 23 mm2,and the FR4 dielectric substrate with thickness of 1mm is adopted.The area of the radiation patch is 10 × 20 mm2,the antenna space is small and can be well integrated into the wireless termination system.The measured results show that the antenna can resonate at 1.73GHz,2.46GHz and 3.48GHz,VSWR<3 bandwidth is 300MHz,450MHz and 600MHz respectively,which can cover a number of wireless application bands.The efficiency of the antenna in the effective operating frequency range is between 60%and 83.4%.