Development of an equivalent circuit model for the design of arrays of electrically small antennas

In this paper, we present a fully parameterized circuit model of an array antenna that relates antenna performance and field coupling to the physical parameters of the elements as represented through a circuit model. We demonstrate that the simplified model can be used as a surrogate for full-wave modeling during the initial optimization steps in array design. The model accounts for mutual coupling between array elements both through the feeding network and through free space. We present a method to calculate the mutual coupling between elements in the array antenna that is parameterized in terms of the size and location of the individual elements, and these circuit models provide excellent agreement with the scattering parameters calculated by the full-wave numerical model. The model is applied to the analysis of a specific built array configuration, and we demonstrate that the simplified circuit model can have strong predictive effects for designing arrays of electrically small antennas and predicting their ultimate performance by comparing with numerical and limited experimental measurements. The study is motivated by high power electromagnetic applications, where arrays of densely space elements can help reduce the antenna size necessary to radiate extremely large power signals.