On bounds of the Q-factor as a function of array antenna directivity

摘要

In this paper we determine the trade-off between the Q-factor and partial (super) directivity for linear arrays of dipoles. The dipoles are densely spaced in a one or two wavelength long array. We compare the bound for port-feed dipoles with the current optimization approach, with optimal currents on the whole dipole area, and also with an enclosing plate. It is interesting to note that port-feed dipoles are close to the optimal current dipoles in the endfire case, for sufficiently many dipoles in the array, for a wide range of directivities. We also show that the optimization problem for the `optimal current' and `the port-feed' cases are very similar and that the Pareto-front (trade-off curve) can be obtained and compared for the different cases.