Design Of Microstrip Filter Antenna Based On FDTD Algorithm

With the rapid development of communication anti-interference technology,the requirements for wireless communication equipment are getting higher and higher.Antennas and filters are necessary components for radio frequency systems,whose performance is extremely important.The traditional antenna can not meet the problem of the development of communication anti-interference technology,so this paper uses the filter antenna design methods based on feeder loading and the synthesis method to study the design of ultra-wideband and miniaturized filter antenna.In addition,the finite-difference time-domain method,which is a method for analyzing and measuring the electromagnetic characteristics of the filter antenna in the electromagnetic field,has been studied to achieve specific application requirements.The main work contents are as follows:Firstly,this paper introduces the basic theory of antenna and filter,and briefly describes the theoretical knowledge of finite-difference time-domain algorithm,including basic equations,numerical stability conditions,absorbing boundary conditions and excitation sources,which is used to verify the antenna and filter.Secondly,using the design method of loading filter on the feeder,this paper designs a microstrip circularly polarized filter antenna with a central frequency of 7.35 GHz and a relative bandwidth of 0.33%.In order to further improve the bandwidth performance of the filter antenna,I designed the ultra-wideband filter antenna with a center frequency of 8.0 GHz and a relative bandwidth of 104.6%,which realizes the performance of ultra-wideband.In the process,this paper used high frequency structure simulator 13.0 to design the filter antenna.At the same time,the finite-difference time-domain algorithm is used to simulate the reflection coefficient of the filter antenna,and then the simulation results are compared with high frequency structure simulator 13.0 to verify the feasibility of the designed filter antenna.In addition,the ultra-wide band filter antenna is processed and measured,which also proves the feasibility of the design.Finally,a single-layer filter antenna with a central frequency of 3.17 GHz and a relative bandwidth of 11.07% is designed by using the comprehensive design method.Using the integrated design method to change the antenna structure and then affect the radiation mode of the antenna to achieve filtering,I designed a double-layer filter antenna,which has a center frequency of 6.6 GHz and a relative bandwidth of 2.3%.As the same as the previous step,high frequency structure simulator 13.0 is also used in this design.The analysis results of finite difference time domain algorithm are compared with the simulation results of high frequency structure simulator 13.0 to verify the feasibility of the designed filter antenna.