Optimization of broadband antenna elements in a periodic planar infinite array

Abstract

It is critically important that mutual coupling effects be properly taken into account when designing wideband antenna elements for use in phased arrays; especially those which require large scanning volumes. In this paper, a method of designing antenna elements for use in large planar phased arrays is presented. The geometric and electrical properties of a single antenna element in an infinite array environment are optimized so that the mutual coupling between the array elements can be properly accounted for. A robust genetic algorithm [1,2] is used to optimize the antenna elements for operation in an infinite array environment with the goal of providing low return loss, high gain, and linear polarization over wide operating bandwidths and large scan angles. An example is presented and its performance is verified by comparison with the results of commercial software package. Similar design approaches have been taken before in [3], although the antenna designs presented possess large thicknesses (up to 0.3λ 0 between radiator and ground) which can limit practical application. Moreover, the analysis approach proposed in [3] is based on a periodic version of the Finite Difference Time Domain (FDTD) technique, whereas the analysis approached developed in this work is based on the Periodic Finite Element Boundary Integral (PFEBI) method.