Characteristics of the Radiating Element of a Planar Vivaldi Antenna Array with Improved Bandwidth

Abstract

Introduction. The conventional approach to extending the operating frequency band of Vivaldi antenna arrays consists in increasing the radiating element length. However, this inevitably leads to an increase in the mass of the entire array, and, therefore, to a rapid growth in the cross-polarization level. Recent studies in this field have mainly focused on techniques for reducing the cross-polarization level. At the same time, the possibility of developing Vivaldi antenna arrays with an extended operating frequency band, primarily without changing the overall dimensions of the elements or the antenna array pitch, remains insufficiently studied.Aim. Design and study of the Vivaldi antenna radiating element that ensures operation of the array in a wider operating frequency band without increasing its overall dimensions and weight.Materials and methods. A numerical study of the characteristics of a unit-cell with periodic boundary conditions on the side faces was carried out in the ANSYS HFSS software. A comparative analysis of the unit-cell characteristics of the prototype antenna array and the proposed design was carried out.Results. The design of the Vivaldi antenna radiating element is presented. The influence of some geometric parameters on the characteristics of the antenna array is studied. A comparative analysis of the unit-cell characteristics of two infinite single-polarization antenna arrays based on a regular Vivaldi element and the proposed solution is carried out. The possibility of improving the antenna array bandwidth by 18.6 % and improving cross-polarization by 15 dB on certain frequencies without increasing the overall dimensions or the antenna array pitch is shown.Conclusion. The proposed Vivaldi antenna design makes it possible to extend its operating frequency band without increasing the overall dimensions. The results of the conducted numerical study should be used when developing antenna arrays based on the proposed solution.