Research Of Ultra-broad Band Omnidirectional Discone And Vivaldi Array Antenna

In today's wireless communication environment,the omnidirectional antenna has been used for 3600°coverage.We can find a lot of cases for the omnidirectional antenna in daily life and military's point to multipoint communication.Such as broadcast?RFIDN radar and space aircraft.On the other hand,as the development of wireless communication,the environment become more and more complicate for the increase of communication protocol's amount and the require for antenna with broad band property come out at the same time.So,for present omnidirectional antenna,it should better have ultra-broad band and keep well omnidirectional radiation simultaneously.In this paper,I launched two research direction for ultra-broad band omnidirectional antenna.First of all,it's about two array formation which are combined by Vivaldi antenna.The another aspect is the research of traditional discone antenna and its radiation property's improvement.In the Vivaldi array's design part,based on the Vivaldi element's ultra-wide impedance band and directional radiation pattern property,a vertically polarized array's structure is proposed firstly which is combined by using eight Vivaldi elements in the H-plane with periodic angle of 45°to build the circular array.Then a type of Vivaldi antenna element which has adjustable H-plane's beam width and the array's simulation and test work has been complete in this paper.The another topology of Vivaldi antenna array is horizontal polarized which is combined by connect some elements in antenna's E-plane.In this part,an array include sixteen element,s design and simulation work has been done.This array is also fabricated and then analysis its property by comparing with the proposed vertically polarized Vivaldi array.As to the traditional discone antenna,it's ultra-broad band and omnidirectional radiation pattern's property are acknowledged by design and simulate a specific discone antenna in this paper.Then,the defect of this type of antenna has also been found,which is antenna's horizontal plane's omnidirectional radiation property will become bad as the frequency increase.So,a new discone include two cones is proposed in this paper and its simulation work is completed.Compare to the traditional discone antenna the proposed antenna realized the improvement of horizontal plane's radiation,including the enhancement of horizontal radiation gain from 0.7GHz to 2GHz.