Research On The Electromagnetic Radiator With Low Directivity

As an important component of wireless communication,antenna has been widely studied.Isotropic antennas have good development prospects in radio frequency identification,direction of arrival estimation and indoor wireless communication by virtue of their electric field components with the same direction and amplitude in all directions.Previous studies have mostly focused on power isotropy,while ignoring the characteristic of polarization isotropy.This paper aims to perfect the related research,besides the design of the power isotropy antenna,attempts have been made to make further progress in the area of polarized isotropic sources of radiation.The main work and achievements include:The first chapter discusses that the current research on isotropic antennas only stays at the level of power isotropy,and summarizes related technical methods and theories.Explains the research significance and breakthrough progress of this article.In the second chapter,the theoretical knowledge involved in this paper is introduced in detail,including the basic parameters of antenna,the correlation theorem of array antenna,the parameters and test methods of RFID tag antenna,the antenna synthesis method and the differential evolution algorithm.It provides a theoretical basis for subsequent research.In the third chapter,an electrically small-size RFID tag antenna with isotropic power is designed.Firstly,the theoretical model of U-shaped three-dimensional dipole is numerically calculated,which proves that this model has power isotropy.Then the theoretical model is improved and optimized according to the actual design requirements,and transformed into a simulation model.Finally,a RFID tag antenna with isotropic power is designed and processed.The theory was successfully applied to the actual model design.Chapter 4 explores polarized isotropic radiation sources.The continuous line source is obtained by the Fourier transform method and the Woodward-Lawson sampling synthesis method,and the discrete line array is obtained by the differential evolution algorithm.Finally,the corresponding initial theoretical solutions under different solving methods is obtained,which laid a theoretical foundation for the actual antenna design in the future.The fifth chapter summarizes the research work of this paper and puts forward the shortcomings of the current work and the direction of improvement in the future.