In this study, performance of the array signal processing algorithms which are used for interference mitigation in radar and communication systems is analyzed while regarding the electromagnetic properties of the antenna elements. In real world applications electromagnetic characteristics of the antenna array have very significant effect on the performance of the algorithms and sometimes may cause a complete fail of the process. In the paper, particularly, effects of the mutual coupling are presented. Performances of the Schelkunoff array synthesis method, least-squares (LS) method and the least mean square (LMS) algorithms for interference suppression in adaptive array with dipole elements are analyzed. Null depth, nulling bandwidth, signal to interference plus noise ratio (SINR) and the changes in the fundamental properties of the array pattern are observed for different scenarios.