Computation of the antenna directivity by using the plane-rectangular scanning

The capacity of a transmitting system to concentrate the radiation in a desired direction is well described by means of the directivity. Its knowledge is very important when using the radiating structure for specialized and high-performance communication links. The computation of the total radiated power, which is obtained by integrating the radiation intensity on the far-field (FF) spherical surface, represents the crucial point in the evaluation of the directivity. The full numerical integration can be used to this end only in numerical simulations, and becomes very time consuming when the computation of the radiation intensity is onerous, as in the case of large arrays. By properly exploiting the nonredundant representations of electromagnetic (EM) fields [1], an efficient Sampling Interpolation (SI) formula has been proposed in [2] for determining the total radiated power from the knowledge of a nonredundant number of the radiation intensity samples. It depends only on the sizes of antenna under test (AUT) and gives an efficient way for the directivity evaluation from simulated or measured samples.