On Realized Gain-Optimal Feeding Coefficients of Antenna Arrays

The feeding coefficients maximizing the realized gain are often solved from an eigenvalue problem. We derive an alternative method for obtaining the optimal feed coefficients in this paper and show that it gives the same solution. The derived method obtains the coefficients from a direct equation. We compare the realized gain obtained with the optimal feeding coefficients to the case where the elements are progressively phased. The examples show that with optimal feeding coefficients the realized gain can be improved in cases where the mutual coupling is high, edge-element effect is strong, or the embedded element patterns are unequal. Also, an example demonstrates that circularly polarized realized gain can be improved in dual polarized array by feeding the elements with optimal coefficients.