Design And FDTD Research On Vivaldi UWB Antenna

With the development of the communication technology, UWB (Ultra Wide Band) wireless communication system application is more and more widespread and bring forward a lot of new challenge to the analysis of conventional electromagnetic field and circuit theory. Some new theories have already explored to solve the coming new problems, for example, time-domain electromagnetics, UWB electromagnetics, computational electromagnetics, theory of probability and so on. And, the RF-circuit design methods are endlessly discovered to suit for the application of UWB.Especially, the designs of the antenna module that is the output entrance to UWB RF systems, which have already become hotspot research subject. In this paper, Vivaldi UWB antenna is analyzed and designed from antenna structure, frequency-domain characteristic and time-domain characteristic three aspects, which is present good technology support for the design of the UWB antenna.As the UWB characteristics are represented at not only directional diagram and impedance bandwidth but also phase distortion. The design of common antenna only stays at the frequency-domain level. In this paper, basic iterative algorithm, lattice division technology, absorb boundary condition, driving source technology and time-domain/frequency-domain far field extrapolation of the FDTD (Finite-Difference Time-Domain) method is firstly discussed and the time-domain characteristics of the Vivaldi antenna are analyzed by using these algorithms.Secondly, in this paper, the four typical UWB antennas of TEM horn antenna, log-periodic antenna, biconical antenna and helical antenna are theoretically analyzed and the UWB antenna design methods are generalized and discussed.Lastly, a kind structure of Vivaldi antenna and new style feed system are presented and the effects of Vivaldi antenna's various parameters on radiation performances are discussed in detail though theoretical analysis and optimization design.Accroding to the result of design, the experiment of prototype is fabricated. The test result indicates that the Vivaldi antenna has better radiation performance that accords with the theory analyses frequency domain on 3.1GHz～...