PROBLEM OF MULTI-CRITERIA OPTIMIZATION OF SELECTION OF AN UNPREPARED HELIDROM

The design of a low-profile antenna array for a base station is considered. The main part of the designis a square dipole array, which is thickened vibrators. The design uses a balun in the form of a snake,which provides the formation of transmission lines and support for radiators with a square contour. Theimprovement of the operating frequency band and the reduction of the height were achieved by placing adielectric material with εr = 2, tan(δ) = 0.002 directly between the dipole and the ground, the electricalthickness of which was 0.16λ at the central frequency of the operating wavelength range. The results of anumerical study of the characteristics of an elementary cell of an antenna array with periodic boundaryconditions on the edges in the ANSYS HFSS software are presented. VSWR of antenna elements and prototypeelement Kathrein 739622 are shown. The dependence of VSWR of antenna element on frequency atdifferent values of dipole radius is shown. The influence of balun size on characteristics of antenna arrayelement is investigated. It was established by calculation that the choice of the dipole radius shortens thedipole by 1.5 times, and the choice of the size of the “Snake” shaped balun ensures a lower antennaheight, without deteriorating the antenna’s characteristics. Radiation patterns in horizontal and verticalplanes are shown. Based on the proposed element, models of finite antenna arrays are developed. Thisantenna usually consists of a row of 4 identical elements installed along a vertical line to form an antennaarray. VSWR and gain of antenna array and also radiation patterns in the horizontal and vertical planesat different frequencies are shown. The results show that due to the proposed original idea of transforminga rectilinear balun into a curvilinear one in the form of a "snake" and thickened vibrators, it was possibleto obtain a design of a basic cellular communication emitter of 1.5 times smaller dimensions, compared tothose antennas used in practice in Kathrein 739622 with good characteristics