Active dipole coupling in an array environment

For a near-field focused wireless power transfer system a parasitically coupled dipole transmit array antenna must be designed. To speed up the analysis time, an approximate input impedance model for parasitically coupled, dipole array antennas has been extended to include the mutual coupling between two active dipole antennas, using input impedances only. The analysis procedure is explained and comparisons with full-wave analysis results are presented. When free Method of Moment analysis software is being used for calculating the input impedances, accuracies comparable to those obtained with full-wave mutual coupling analysis are obtained. The gain in computation speed is about two orders of magnitude. A further order of magnitude speed improvement may be obtained by simplifying the analysis, assuming amongst others infinitely thin dipoles for the in-array coupling calculations. The cost for this further speed improvement is in a degradation of the accuracy obtained. The accuracy however is still good enough to use the fast analysis method in an iterative way for generating a pre-design. This pre-design may be fine-tuned into a final design using a minimum number of full-wave analysis runs, thus reducing the overall design time.