Influence of Aperture of Radiating Strip Structure on Electrodynamic Characteristics of Patch Antenna

Abstract

The paper presents the results of numerical modeling of the electrodynamic characteristics of a Vivaldi type patch antenna based on a circular disk resonator. The modeling was carried out using the semi-open resonator model by the finite element method (FEM) implemented in the HFFS package. The antenna was fed using a coplanar line segment. The antenna elements were placed over a grounded plane. The influence of design parameters and the function determining the curvature of the exponentially expanding slot discontinuity on the frequency, energy and polarization characteristics was investigated. It was established that with a certain selection of variable parameters, such an antenna can be matched with external circuits in the range from 7.03 GHz to 20 GHz with a level of VSWR values not exceeding 1.92. In the amplitude-frequency characteristic, fairly wide frequency bands with almost perfect matching are observed. The choice of the type of excitation element in the form of a section of the coplanar line made it possible to exclude additional elements inherent in Vivaldi antennas, namely, a section of the auxiliary strip line and a balancing resonator. This kind of antenna allows to form radiation patterns of various shapes from single-sided to cosecant quadrate. At the same time, in some intervals of observation angles, the formed fields turn out to be elliptically polarized with an ellipticity coefficient close to unity. The combination of the obtained results makes it possible to predict the use of this kind of antennas for operation with broadband signals.