FDTD-Based Modeling And Simulation Design Of UWB Antennas

Nowadays, the Ultra-Wideband (UWB) technology, which transmits UWB signal such as short pulse or modulated short pulse, has attracted worldwide attention. The UWB signal whose fractional bandwidth exceed 20% or bandwidth exceed 500 MHz should be transmitted and received by UWB antennas. It makes antenna design a crucial part in the overall UWB system. Traditional analysis method can not always fit in with the needs of UWB antennas, and the measurements of real antennas may always be limited by objective conditions. Therefore, more and more attentions are devoted to computer simulation for the design of UWB antennas.In this paper, with the Finite Difference Time Domain (FDTD) algorithm, the modeling and simulation design of typical UWB antennas are studied mostly. The other works include the introduction and implement of the FDTD algorithm, the study of FDTD visual modeling algorithm, the development of FDTD modeling simulation system for typical UWB antennas, and the simulations, optimizations, fabrications and experimental measurements of UWB antennas.In the research of modeling and simulation method for UWB antennas, a favourable FDTD modeling algorithm is presented. With this algorithm, only a few parameters are needed for FDTD mesh generation of an UWB antenna. The modeling algorithm, with the merits of simpleness and convenience, has a good application in parametric and optimization analysises. Meanwhile, with the combination of FDTD modeling algorithm and FDTD simulation software, a FDTD modeling simulation system with convenient user interface is developed for the design and simulation of UWB antennas. With it, detailed analysis results of UWB antennas such as TEM horn antenna and antennas with the bandwidth of 3.1～10.6GHz are given. It is shown that the FDTD simulation results of UWB antennas in this paper accord with theoretical analysises. In addition, an optimization program is developed using Genetic Algorithm (GA), and the optimization scheme is also presented and used in the optimization design of TEM horn antenna. The results show that the optimization scheme is feasible and effective.For the validation of the reliability of the antanna designs, several UWB antenna prototypes are fabricated and measured using vector network analyzer. It is shown that the experimental measurements accord with the design purpose and the simulation results. Therefore, the FDTD based modeling and simulation design method for UWB antennas proposed in this paper has high reliability and good prospects in future antenna design.