Directivity and Mutual Coupling of Array Antenna

Mutual radiation resistance(MRR) is a real part of mutual impedance(MI), when the currents on the antenna are expressed by a real function. In this study, to consider the MRR and MI functions, the hypothesis stating that “the primitively estimated array gain with mutual coupling considered under the single-mode current assumption (PEAGMS)” corresponds to “the array directivity with an isolated element pattern used (ADIEU)” is presented and verified analytically for a two-element array and numerically for a l0-element array. The results show that the PEAGMS agrees very well with the ADIEU. Thus, from an engineering point of view, calculating directivity using pattern integration is equivalent to considering mutual coupling under a single-mode current assumption.