Mutual coupling modelling in presence of diffraction effects for different types of microstrip radiating elements

In this paper the quality of a model of an antenna array which takes into account mutual coupling and aperture edge diffraction effects is investigated. The model consists in determination of the coupling coefficients between radiating elements and approximation of the active elements radiation patterns. This approximation is based on radiation patterns of the isolated elements which take into account the aperture edge diffraction effects. It is shown that due to undesired the surface wave effects, the investigated model is more accurate when an aperture coupled microstrip antenna array is placed on a thin substrate than on thick.