Research On Ultra-wideband Vivaldi Antenna And Tightly Coupled Dipole Array Antenn

Based on the development needs of wireless communication technology and relying on related engineering projects,this article mainly researches and designs several ultra-wideband antennas and arrays,including ultra-wideband balanced antipodal Vivaldi antenna and its improved version,ultra-wideband vertical tightly coupled dipole array,ultra-wideband Broadband dual-polarization horizontal tightly coupled dipole array.The specific research content is as follows:（1）Several typical structures of Vivaldi antennas are studied,the broadband characteristics of Vivaldi antennas are analyzed theoretically,and the design methods of Vivaldi antennas are introduced.Aiming at the problem of the peak deflection of the E-plane pattern of the balance antipodal Vivaldi antenna,an elliptical groove is opened on the basis of the structure of the balance antipodal Vivaldi antenna,and a semi-elliptical guide medium with the same dielectric constant is added to improve the peak deviation of the E-plane.Phenomenon,and increase the gain.In the final test on the real object,the improved balanced butt Vivaldi antenna has S₁₁ less than-10d B in the 2-22.8GHz frequency band.（2）Due to the high profile height of the Vivaldi antenna,it is not conducive to array formation and miniaturization.This chapter studies an ultra-wideband single-polarization vertical tightly coupled dipole array antenna.Based on the theoretical study of tightly coupled antenna arrays and analysis of the principle of bandwidth expansion,the combination of ADS and HFSS is used to load the tightly coupled array before and after Marchand balun.The equivalent circuit is analyzed and modeled,and the tightly coupled dipole antenna unit is finally designed.Then,the antenna element is a limited 4×4 array,and the performance of the edge element is found to be poor through simulation.The analysis is caused by the edge truncation effect,so the edge truncation process is performed on this array.After the truncation process,the Active S₁₁of the center,corner and edge ports of the array is less than-10d B in the 3.8-9.8GHz frequency band.In the final processing and assembly of the truncated array,comparing the measured and simulated results,S₁₁ and the pattern are in good agreement.（3）In view of the fact that the profile of the vertical tightly coupled dipole array antenna in the previous chapter is still relatively high,and the dual polarization needs to be crossed,the structural strength is limited.In this chapter,we design a dual-polarization horizontal tight-coupling dipole array antenna for X-band,and design a dual-polarization tight-coupling dipole antenna unit by coaxial feeding.Based on this unit,a 4×4 dual-polarization array is designed.The final realization is in the 5.5-16.2GHz frequency band,and the simulated Active S₁₁ of each port is less than-10d B.The actual size of the processed 4×4 array is only 48.6×48.6×14.9mm3.The measured pattern is in good agreement with the simulation results.The measured S₁₁ is slightly worse than the simulation results,but it fully meets the design requirements of the X-band.