Equivalent Circuit Modelling of an L-shaped Patch Antennaby Optimizing the Lumped Elements Using Differential Evolution Algorithm

Abstract

L-shaped patch antenna (LPA) is formed by combining two monopole patch radiators. Proper modelling of a LPA using lumped elements is crucial in antenna design and analysis. In this study, a novel equivalent circuit (EC) modelingof an LPAusing differential evolution (DE) optimization algorithmis presented. Two parallel brancheseach represents the monopole patch radiator compose the EC topology.In eachbranch, a serial resistance and inductance pair stands for patch conductor, a parallel resistance and capacitancepair symbolizes the dielectric substrate. The expressions of theseeightlumpedelementsenclosing the antenna’s physical and electrical parameters accompanyingwith optimization variables are constituted considering the element definitions of microstrip transmission line(MTL). Return loss equationis derived through input impedance equation of the EC model. The variables are then optimallyfoundby fitting the calculated return loss to the simulated results by DEalgorithm. The proposed ECmodelisthenverified through resultsof simulated andmeasured LPA.Moreover, real and imaginary parts of theECinput impedanceare comparatively calculated. Theseresults showthat the proposed EC model gives almost the same results in terms of important antenna parameters