Abstract: A blind spot analysis is made in rectangular waveguide end-slot phased arrays of a triangular arrangement by using the method of moments (MoM). By increasing array elements of the E plane and H plane, the reflection coefficients versus scanning for the central elements in various sized arrays have been calculated. As the number of array elements of the E plane increases, the blind effect changes greatly, and as the number of array elements of the H plane increases, it will almost not change. By analyzing the coupling coefficient between array elements, an explanation of this phenomenon is given. In the analysis of the blind spot problem, the relationship between the radiation pattern of the center element and the reflection coefficient has been derived. We find their disunity in describing the blind effect. The sufficient condition for the unity that the array be equal scale excited and that the phase of the reflection coefficient be zero(resonance) is obtained.

Key words: waveguide end-slot phased arrays, triangular lattice, scan blind spot, element pattern, mutual coupling