A novel method for optimization of flat monopole antennas with the help of a universal definition for geometric shapes

Abstract

In this research, a novel method is proposed optimization of flatted ultra-wideband monopole antennas. In this method, the shape of the antennas is described in general terms. This general description allows the antennas to take all kinds of shapes during the optimization process and finally, an optimal form for an ultra-wideband monopole is obtained. The parameters of this general description are obtained according to the design constraints in a two-stage optimization process (including global and local optimization). The optimization to achieve the acceptable impedance matching in the working band and reduction of the distortion of the radiation waves is to be done. Due to the efficiency of the optimization method, by applying strict-tightening constrictions on the size of the antenna, smaller antennas with the same performance as the best flat monopole antennas are designed. The main optimization program runs in Matlab Software, but the analysis of antennas at each stage of optimization is executed in the CST Microwave Studio Software. For this purpose, with the help of Visual Basic for Applications programming, an automated link is created between the MATLAB Software and CST Microwave Studio Software. The optimization results showed the ability of this method to design very small antennas with desired functional characteristics. The results showed that the return loss for the entire operational spectrum is below − 10 dB. Also, the correlation coefficient of the proposed planar super wideband monopole antenna has different values in different radiation angles.